sphinx.addnodesdocument)}( rawsourcechildren]( translations LanguagesNode)}(hhh](h pending_xref)}(hhh]docutils.nodesTextChinese (Simplified)}parenthsba attributes}(ids]classes]names]dupnames]backrefs] refdomainstdreftypedoc reftarget#/translations/zh_CN/locking/seqlockmodnameN classnameN refexplicitutagnamehhh ubh)}(hhh]hChinese (Traditional)}hh2sbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget#/translations/zh_TW/locking/seqlockmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hItalian}hhFsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget#/translations/it_IT/locking/seqlockmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hJapanese}hhZsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget#/translations/ja_JP/locking/seqlockmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hKorean}hhnsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget#/translations/ko_KR/locking/seqlockmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hSpanish}hhsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget#/translations/sp_SP/locking/seqlockmodnameN classnameN refexplicituh1hhh ubeh}(h]h ]h"]h$]h&]current_languageEnglishuh1h hh _documenthsourceNlineNubhsection)}(hhh](htitle)}(h&Sequence counters and sequential locksh]h&Sequence counters and sequential locks}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhhh=/var/lib/git/docbuild/linux/Documentation/locking/seqlock.rsthKubh)}(hhh](h)}(h Introductionh]h Introduction}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhhhhhKubh paragraph)}(hX4Sequence counters are a reader-writer consistency mechanism with lockless readers (read-only retry loops), and no writer starvation. They are used for data that's rarely written to (e.g. system time), where the reader wants a consistent set of information and is willing to retry if that information changes.h]hX6Sequence counters are a reader-writer consistency mechanism with lockless readers (read-only retry loops), and no writer starvation. They are used for data that’s rarely written to (e.g. system time), where the reader wants a consistent set of information and is willing to retry if that information changes.}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhhhhubh)}(hX}A data set is consistent when the sequence count at the beginning of the read side critical section is even and the same sequence count value is read again at the end of the critical section. The data in the set must be copied out inside the read side critical section. If the sequence count has changed between the start and the end of the critical section, the reader must retry.h]hX}A data set is consistent when the sequence count at the beginning of the read side critical section is even and the same sequence count value is read again at the end of the critical section. The data in the set must be copied out inside the read side critical section. If the sequence count has changed between the start and the end of the critical section, the reader must retry.}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhhhhubh)}(hXHWriters increment the sequence count at the start and the end of their critical section. After starting the critical section the sequence count is odd and indicates to the readers that an update is in progress. At the end of the write side critical section the sequence count becomes even again which lets readers make progress.h]hXHWriters increment the sequence count at the start and the end of their critical section. After starting the critical section the sequence count is odd and indicates to the readers that an update is in progress. At the end of the write side critical section the sequence count becomes even again which lets readers make progress.}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhhhhubh)}(hXSA sequence counter write side critical section must never be preempted or interrupted by read side sections. Otherwise the reader will spin for the entire scheduler tick due to the odd sequence count value and the interrupted writer. If that reader belongs to a real-time scheduling class, it can spin forever and the kernel will livelock.h]hXSA sequence counter write side critical section must never be preempted or interrupted by read side sections. Otherwise the reader will spin for the entire scheduler tick due to the odd sequence count value and the interrupted writer. If that reader belongs to a real-time scheduling class, it can spin forever and the kernel will livelock.}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhhhhubh)}(hThis mechanism cannot be used if the protected data contains pointers, as the writer can invalidate a pointer that the reader is following.h]hThis mechanism cannot be used if the protected data contains pointers, as the writer can invalidate a pointer that the reader is following.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK!hhhhubhtarget)}(h.. _seqcount_t:h]h}(h]h ]h"]h$]h&]refid seqcount-tuh1jhK%hhhhhhubeh}(h] introductionah ]h"] introductionah$]h&]uh1hhhhhhhhKubh)}(hhh](h)}(h"Sequence counters (``seqcount_t``)h](hSequence counters (}(hj)hhhNhNubhliteral)}(h``seqcount_t``h]h seqcount_t}(hj3hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj)ubh)}(hj)hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhj&hhhhhK(ubh)}(hThis is the raw counting mechanism, which does not protect against multiple writers. Write side critical sections must thus be serialized by an external lock.h]hThis is the raw counting mechanism, which does not protect against multiple writers. Write side critical sections must thus be serialized by an external lock.}(hjKhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK*hj&hhubh)}(hXBIf the write serialization primitive is not implicitly disabling preemption, preemption must be explicitly disabled before entering the write side section. If the read section can be invoked from hardirq or softirq contexts, interrupts or bottom halves must also be respectively disabled before entering the write section.h]hXBIf the write serialization primitive is not implicitly disabling preemption, preemption must be explicitly disabled before entering the write side section. If the read section can be invoked from hardirq or softirq contexts, interrupts or bottom halves must also be respectively disabled before entering the write section.}(hjYhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK.hj&hhubh)}(hIf it's desired to automatically handle the sequence counter requirements of writer serialization and non-preemptibility, use :ref:`seqlock_t` instead.h](hIf it’s desired to automatically handle the sequence counter requirements of writer serialization and non-preemptibility, use }(hjghhhNhNubh)}(h:ref:`seqlock_t`h]hinline)}(hjqh]h seqlock_t}(hjuhhhNhNubah}(h]h ](xrefstdstd-refeh"]h$]h&]uh1jshjoubah}(h]h ]h"]h$]h&]refdoclocking/seqlock refdomainjreftyperef refexplicitrefwarn reftarget seqlock_tuh1hhhhK4hjgubh instead.}(hjghhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK4hj&hhubh)}(hInitialization::h]hInitialization:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK8hj&hhubh literal_block)}(h/* dynamic */ seqcount_t foo_seqcount; seqcount_init(&foo_seqcount); /* static */ static seqcount_t foo_seqcount = SEQCNT_ZERO(foo_seqcount); /* C99 struct init */ struct { .seq = SEQCNT_ZERO(foo.seq), } foo;h]h/* dynamic */ seqcount_t foo_seqcount; seqcount_init(&foo_seqcount); /* static */ static seqcount_t foo_seqcount = SEQCNT_ZERO(foo_seqcount); /* C99 struct init */ struct { .seq = SEQCNT_ZERO(foo.seq), } foo;}hjsbah}(h]h ]h"]h$]h&] xml:spacepreserveuh1jhhhK:hj&hhubh)}(h Write path::h]h Write path:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKFhj&hhubj)}(h/* Serialized context with disabled preemption */ write_seqcount_begin(&foo_seqcount); /* ... [[write-side critical section]] ... */ write_seqcount_end(&foo_seqcount);h]h/* Serialized context with disabled preemption */ write_seqcount_begin(&foo_seqcount); /* ... [[write-side critical section]] ... */ write_seqcount_end(&foo_seqcount);}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhKHhj&hhubh)}(h Read path::h]h Read path:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKPhj&hhubj)}(hdo { seq = read_seqcount_begin(&foo_seqcount); /* ... [[read-side critical section]] ... */ } while (read_seqcount_retry(&foo_seqcount, seq));h]hdo { seq = read_seqcount_begin(&foo_seqcount); /* ... [[read-side critical section]] ... */ } while (read_seqcount_retry(&foo_seqcount, seq));}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhKRhj&hhubj)}(h.. _seqcount_locktype_t:h]h}(h]h ]h"]h$]h&]jseqcount-locktype-tuh1jhKZhj&hhhhubh)}(hhh](h)}(hASequence counters with associated locks (``seqcount_LOCKNAME_t``)h](h)Sequence counters with associated locks (}(hjhhhNhNubj2)}(h``seqcount_LOCKNAME_t``h]hseqcount_LOCKNAME_t}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubh)}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhjhhhhhK]ubh)}(hXBAs discussed at :ref:`seqcount_t`, sequence count write side critical sections must be serialized and non-preemptible. This variant of sequence counters associate the lock used for writer serialization at initialization time, which enables lockdep to validate that the write side critical sections are properly serialized.h](hAs discussed at }(hj$hhhNhNubh)}(h:ref:`seqcount_t`h]jt)}(hj.h]h seqcount_t}(hj0hhhNhNubah}(h]h ](jstdstd-refeh"]h$]h&]uh1jshj,ubah}(h]h ]h"]h$]h&]refdocj refdomainj:reftyperef refexplicitrefwarnj seqcount_tuh1hhhhK_hj$ubhX!, sequence count write side critical sections must be serialized and non-preemptible. This variant of sequence counters associate the lock used for writer serialization at initialization time, which enables lockdep to validate that the write side critical sections are properly serialized.}(hj$hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK_hjhhubh)}(hX=This lock association is a NOOP if lockdep is disabled and has neither storage nor runtime overhead. If lockdep is enabled, the lock pointer is stored in struct seqcount and lockdep's "lock is held" assertions are injected at the beginning of the write side critical section to validate that it is properly protected.h]hXCThis lock association is a NOOP if lockdep is disabled and has neither storage nor runtime overhead. If lockdep is enabled, the lock pointer is stored in struct seqcount and lockdep’s “lock is held” assertions are injected at the beginning of the write side critical section to validate that it is properly protected.}(hjVhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKehjhhubh)}(hxFor lock types which do not implicitly disable preemption, preemption protection is enforced in the write side function.h]hxFor lock types which do not implicitly disable preemption, preemption protection is enforced in the write side function.}(hjdhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKkhjhhubh)}(hBThe following sequence counters with associated locks are defined:h]hBThe following sequence counters with associated locks are defined:}(hjrhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKnhjhhubh block_quote)}(h- ``seqcount_spinlock_t`` - ``seqcount_raw_spinlock_t`` - ``seqcount_rwlock_t`` - ``seqcount_mutex_t`` - ``seqcount_ww_mutex_t`` h]h bullet_list)}(hhh](h list_item)}(h``seqcount_spinlock_t``h]h)}(hjh]j2)}(hjh]hseqcount_spinlock_t}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1hhhhKphjubah}(h]h ]h"]h$]h&]uh1jhjubj)}(h``seqcount_raw_spinlock_t``h]h)}(hjh]j2)}(hjh]hseqcount_raw_spinlock_t}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1hhhhKqhjubah}(h]h ]h"]h$]h&]uh1jhjubj)}(h``seqcount_rwlock_t``h]h)}(hjh]j2)}(hjh]hseqcount_rwlock_t}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1hhhhKrhjubah}(h]h ]h"]h$]h&]uh1jhjubj)}(h``seqcount_mutex_t``h]h)}(hjh]j2)}(hjh]hseqcount_mutex_t}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1hhhhKshjubah}(h]h ]h"]h$]h&]uh1jhjubj)}(h``seqcount_ww_mutex_t`` h]h)}(h``seqcount_ww_mutex_t``h]j2)}(hjh]hseqcount_ww_mutex_t}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1hhhhKthj ubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]bullet-uh1jhhhKphjubah}(h]h ]h"]h$]h&]uh1jhhhKphjhhubh)}(h}The sequence counter read and write APIs can take either a plain seqcount_t or any of the seqcount_LOCKNAME_t variants above.h]h}The sequence counter read and write APIs can take either a plain seqcount_t or any of the seqcount_LOCKNAME_t variants above.}(hj<hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKvhjhhubh)}(hEInitialization (replace "LOCKNAME" with one of the supported locks)::h]hHInitialization (replace “LOCKNAME” with one of the supported locks):}(hjJhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKyhjhhubj)}(hX&/* dynamic */ seqcount_LOCKNAME_t foo_seqcount; seqcount_LOCKNAME_init(&foo_seqcount, &lock); /* static */ static seqcount_LOCKNAME_t foo_seqcount = SEQCNT_LOCKNAME_ZERO(foo_seqcount, &lock); /* C99 struct init */ struct { .seq = SEQCNT_LOCKNAME_ZERO(foo.seq, &lock), } foo;h]hX&/* dynamic */ seqcount_LOCKNAME_t foo_seqcount; seqcount_LOCKNAME_init(&foo_seqcount, &lock); /* static */ static seqcount_LOCKNAME_t foo_seqcount = SEQCNT_LOCKNAME_ZERO(foo_seqcount, &lock); /* C99 struct init */ struct { .seq = SEQCNT_LOCKNAME_ZERO(foo.seq, &lock), } foo;}hjXsbah}(h]h ]h"]h$]h&]jjuh1jhhhK{hjhhubh)}(h}Write path: same as in :ref:`seqcount_t`, while running from a context with the associated write serialization lock acquired.h](hWrite path: same as in }(hjfhhhNhNubh)}(h:ref:`seqcount_t`h]jt)}(hjph]h seqcount_t}(hjrhhhNhNubah}(h]h ](jstdstd-refeh"]h$]h&]uh1jshjnubah}(h]h ]h"]h$]h&]refdocj refdomainj|reftyperef refexplicitrefwarnj seqcount_tuh1hhhhKhjfubhU, while running from a context with the associated write serialization lock acquired.}(hjfhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh)}(h(Read path: same as in :ref:`seqcount_t`.h](hRead path: same as in }(hjhhhNhNubh)}(h:ref:`seqcount_t`h]jt)}(hjh]h seqcount_t}(hjhhhNhNubah}(h]h ](jstdstd-refeh"]h$]h&]uh1jshjubah}(h]h ]h"]h$]h&]refdocj refdomainjreftyperef refexplicitrefwarnj seqcount_tuh1hhhhKhjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubj)}(h.. _seqcount_latch_t:h]h}(h]h ]h"]h$]h&]jseqcount-latch-tuh1jhKhjhhhhubeh}(h](;sequence-counters-with-associated-locks-seqcount-lockname-tjeh ]h"](=sequence counters with associated locks (seqcount_lockname_t)seqcount_locktype_teh$]h&]uh1hhj&hhhhhK]expect_referenced_by_name}jjsexpect_referenced_by_id}jjsubh)}(hhh](h)}(h.Latch sequence counters (``seqcount_latch_t``)h](hLatch sequence counters (}(hjhhhNhNubj2)}(h``seqcount_latch_t``h]hseqcount_latch_t}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubh)}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhjhhhhhKubh)}(hXLatch sequence counters are a multiversion concurrency control mechanism where the embedded seqcount_t counter even/odd value is used to switch between two copies of protected data. This allows the sequence counter read path to safely interrupt its own write side critical section.h]hXLatch sequence counters are a multiversion concurrency control mechanism where the embedded seqcount_t counter even/odd value is used to switch between two copies of protected data. This allows the sequence counter read path to safely interrupt its own write side critical section.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh)}(hUse seqcount_latch_t when the write side sections cannot be protected from interruption by readers. This is typically the case when the read side can be invoked from NMI handlers.h]hUse seqcount_latch_t when the write side sections cannot be protected from interruption by readers. This is typically the case when the read side can be invoked from NMI handlers.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh)}(h4Check `write_seqcount_latch()` for more information.h](hCheck }(hj!hhhNhNubhtitle_reference)}(h`write_seqcount_latch()`h]hwrite_seqcount_latch()}(hj+hhhNhNubah}(h]h ]h"]h$]h&]uh1j)hj!ubh for more information.}(hj!hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubj)}(h.. _seqlock_t:h]h}(h]h ]h"]h$]h&]j seqlock-tuh1jhKhjhhhhubeh}(h]((latch-sequence-counters-seqcount-latch-tjeh ]h"](*latch sequence counters (seqcount_latch_t)seqcount_latch_teh$]h&]uh1hhj&hhhhhKj}jTjsj}jjsubeh}(h](sequence-counters-seqcount-tjeh ]h"](sequence counters (seqcount_t) seqcount_teh$]h&]uh1hhhhhhhhK(j}j_jsj}jjsubh)}(hhh](h)}(h Sequential locks (``seqlock_t``)h](hSequential locks (}(hjghhhNhNubj2)}(h ``seqlock_t``h]h seqlock_t}(hjohhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjgubh)}(hjghhhNhNubeh}(h]h ]h"]h$]h&]uh1hhjdhhhhhKubh)}(hThis contains the :ref:`seqcount_t` mechanism earlier discussed, plus an embedded spinlock for writer serialization and non-preemptibility.h](hThis contains the }(hjhhhNhNubh)}(h:ref:`seqcount_t`h]jt)}(hjh]h seqcount_t}(hjhhhNhNubah}(h]h ](jstdstd-refeh"]h$]h&]uh1jshjubah}(h]h ]h"]h$]h&]refdocj refdomainjreftyperef refexplicitrefwarnj seqcount_tuh1hhhhKhjubhh mechanism earlier discussed, plus an embedded spinlock for writer serialization and non-preemptibility.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjdhhubh)}(hIf the read side section can be invoked from hardirq or softirq context, use the write side function variants which disable interrupts or bottom halves respectively.h]hIf the read side section can be invoked from hardirq or softirq context, use the write side function variants which disable interrupts or bottom halves respectively.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjdhhubh)}(hInitialization::h]hInitialization:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjdhhubj)}(h/* dynamic */ seqlock_t foo_seqlock; seqlock_init(&foo_seqlock); /* static */ static DEFINE_SEQLOCK(foo_seqlock); /* C99 struct init */ struct { .seql = __SEQLOCK_UNLOCKED(foo.seql) } foo;h]h/* dynamic */ seqlock_t foo_seqlock; seqlock_init(&foo_seqlock); /* static */ static DEFINE_SEQLOCK(foo_seqlock); /* C99 struct init */ struct { .seql = __SEQLOCK_UNLOCKED(foo.seql) } foo;}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhKhjdhhubh)}(h Write path::h]h Write path:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjdhhubj)}(hkwrite_seqlock(&foo_seqlock); /* ... [[write-side critical section]] ... */ write_sequnlock(&foo_seqlock);h]hkwrite_seqlock(&foo_seqlock); /* ... [[write-side critical section]] ... */ write_sequnlock(&foo_seqlock);}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhKhjdhhubh)}(hRead path, three categories:h]hRead path, three categories:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjdhhubhenumerated_list)}(hhh](j)}(hXcNormal Sequence readers which never block a writer but they must retry if a writer is in progress by detecting change in the sequence number. Writers do not wait for a sequence reader:: do { seq = read_seqbegin(&foo_seqlock); /* ... [[read-side critical section]] ... */ } while (read_seqretry(&foo_seqlock, seq)); h](h)}(hNormal Sequence readers which never block a writer but they must retry if a writer is in progress by detecting change in the sequence number. Writers do not wait for a sequence reader::h]hNormal Sequence readers which never block a writer but they must retry if a writer is in progress by detecting change in the sequence number. Writers do not wait for a sequence reader:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjubj)}(hdo { seq = read_seqbegin(&foo_seqlock); /* ... [[read-side critical section]] ... */ } while (read_seqretry(&foo_seqlock, seq));h]hdo { seq = read_seqbegin(&foo_seqlock); /* ... [[read-side critical section]] ... */ } while (read_seqretry(&foo_seqlock, seq));}hj$sbah}(h]h ]h"]h$]h&]jjuh1jhhhKhjubeh}(h]h ]h"]h$]h&]uh1jhjhhhhhNubj)}(hXLocking readers which will wait if a writer or another locking reader is in progress. A locking reader in progress will also block a writer from entering its critical section. This read lock is exclusive. Unlike rwlock_t, only one locking reader can acquire it:: read_seqlock_excl(&foo_seqlock); /* ... [[read-side critical section]] ... */ read_sequnlock_excl(&foo_seqlock); h](h)}(hXLocking readers which will wait if a writer or another locking reader is in progress. A locking reader in progress will also block a writer from entering its critical section. This read lock is exclusive. Unlike rwlock_t, only one locking reader can acquire it::h]hXLocking readers which will wait if a writer or another locking reader is in progress. A locking reader in progress will also block a writer from entering its critical section. This read lock is exclusive. Unlike rwlock_t, only one locking reader can acquire it:}(hj<hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj8ubj)}(hrread_seqlock_excl(&foo_seqlock); /* ... [[read-side critical section]] ... */ read_sequnlock_excl(&foo_seqlock);h]hrread_seqlock_excl(&foo_seqlock); /* ... [[read-side critical section]] ... */ read_sequnlock_excl(&foo_seqlock);}hjJsbah}(h]h ]h"]h$]h&]jjuh1jhhhKhj8ubeh}(h]h ]h"]h$]h&]uh1jhjhhhhhNubj)}(hXConditional lockless reader (as in 1), or locking reader (as in 2), according to a passed marker. This is used to avoid lockless readers starvation (too much retry loops) in case of a sharp spike in write activity. First, a lockless read is tried (even marker passed). If that trial fails (odd sequence counter is returned, which is used as the next iteration marker), the lockless read is transformed to a full locking read and no retry loop is necessary:: /* marker; even initialization */ int seq = 0; do { read_seqbegin_or_lock(&foo_seqlock, &seq); /* ... [[read-side critical section]] ... */ } while (need_seqretry(&foo_seqlock, seq)); done_seqretry(&foo_seqlock, seq); h](h)}(hXConditional lockless reader (as in 1), or locking reader (as in 2), according to a passed marker. This is used to avoid lockless readers starvation (too much retry loops) in case of a sharp spike in write activity. First, a lockless read is tried (even marker passed). If that trial fails (odd sequence counter is returned, which is used as the next iteration marker), the lockless read is transformed to a full locking read and no retry loop is necessary::h]hXConditional lockless reader (as in 1), or locking reader (as in 2), according to a passed marker. This is used to avoid lockless readers starvation (too much retry loops) in case of a sharp spike in write activity. First, a lockless read is tried (even marker passed). If that trial fails (odd sequence counter is returned, which is used as the next iteration marker), the lockless read is transformed to a full locking read and no retry loop is necessary:}(hjbhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj^ubj)}(h/* marker; even initialization */ int seq = 0; do { read_seqbegin_or_lock(&foo_seqlock, &seq); /* ... [[read-side critical section]] ... */ } while (need_seqretry(&foo_seqlock, seq)); done_seqretry(&foo_seqlock, seq);h]h/* marker; even initialization */ int seq = 0; do { read_seqbegin_or_lock(&foo_seqlock, &seq); /* ... 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kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j__read_seqcount_begin (C macro)c.__read_seqcount_beginhNtauh1jhjhhhNhNubj)}(hhh](j)}(h__read_seqcount_beginh]j)}(h__read_seqcount_beginh]j)}(h__read_seqcount_beginh]j)}(hjh]h__read_seqcount_begin}(hjhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjubah}(h]h ](jjeh"]h$]h&]jjuh1jhjhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubah}(h]h ]h"]h$]h&]jjjuh1jjjhjhhhjhMubah}(h]jah ](jjeh"]h$]h&]jj)jhuh1jhjhMhjhhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhjhhhjhMubeh}(h]h ](jmacroeh"]h$]h&]jjjjjjjjjuh1jhhhjhNhNubh)}(h``__read_seqcount_begin (s)``h]j2)}(hjh]h__read_seqcount_begin (s)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjhhubj)}(h begin a seqcount_t read section h]h)}(hbegin a seqcount_t read sectionh]hbegin a seqcount_t read section}(hj hhhNhNubah}(h]h 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hhhj hM9ubah}(h]j ah ](jjeh"]h$]h&]jj)jhuh1jhj hM9hj hhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhj hhhj hM9ubeh}(h]h ](jmacroeh"]h$]h&]jjjj jj jjjuh1jhhhjhNhNubh)}(h``raw_read_seqcount (s)``h]j2)}(hj h]hraw_read_seqcount (s)}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM;hjhhubj)}(h&read the raw seqcount_t counter value h]h)}(h%read the raw seqcount_t counter valueh]h%read the raw seqcount_t counter value}(hj' hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM/hj# ubah}(h]h ]h"]h$]h&]uh1jhj5 hM/hjhhubjK)}(hXs**Parameters** ``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants **Description** raw_read_seqcount opens a read critical section of the given seqcount_t, without any lockdep checking, and without checking or masking the sequence counter LSB. 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Calling code is responsible for handling that.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM2hj< ubh)}(h **Return**h]jU)}(hj h]hReturn}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM7hj< ubh)}(h+count to be passed to read_seqcount_retry()h]h+count to be passed to read_seqcount_retry()}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM7hj< ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j raw_seqcount_try_begin (C macro)c.raw_seqcount_try_beginhNtauh1jhjhhhNhNubj)}(hhh](j)}(hraw_seqcount_try_beginh]j)}(hraw_seqcount_try_beginh]j)}(hraw_seqcount_try_beginh]j)}(hj h]hraw_seqcount_try_begin}(hj hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMRubah}(h]h ]h"]h$]h&]jjjuh1jjjhj hhhj hMRubah}(h]j ah ](jjeh"]h$]h&]jj)jhuh1jhj hMRhj hhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhj hhhj hMRubeh}(h]h ](jmacroeh"]h$]h&]jjjj8 jj8 jjjuh1jhhhjhNhNubh)}(h%``raw_seqcount_try_begin (s, start)``h]j2)}(hj> h]h!raw_seqcount_try_begin (s, start)}(hj@ hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj< ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMThjhhubj)}(hSbegin a seqcount_t read critical section w/o lockdep and w/o counter stabilization h]h)}(hRbegin a seqcount_t read critical section w/o lockdep and w/o counter stabilizationh]hRbegin a seqcount_t read critical section w/o lockdep and w/o counter stabilization}(hjX hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMBhjT ubah}(h]h ]h"]h$]h&]uh1jhjf hMBhjhhubjK)}(hX.**Parameters** ``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants ``start`` count to be passed to read_seqcount_retry() **Description** Similar to raw_seqcount_begin(), except it enables eliding the critical section entirely if odd, instead of doing the speculation knowing it will fail. 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It will save a single branching instruction. **Return** count to be passed to read_seqcount_retry()h](h)}(h**Parameters**h]jU)}(hj h]h Parameters}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM]hj ubjk)}(hhh]jp)}(hG``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants h](jv)}(h``s``h]j2)}(hjh]hs}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM[hjubj)}(hhh]h)}(h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variantsh]h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants}(hj3hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj/hM[hj0ubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1johj/hM[hjubah}(h]h ]h"]h$]h&]uh1jjhj ubh)}(h**Description**h]jU)}(hjUh]h Description}(hjWhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjSubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM]hj ubh)}(hXCraw_seqcount_begin opens a read critical section of the given seqcount_t. 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It will save a single branching instruction.}(hjzhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMchj ubh)}(h **Return**h]jU)}(hjh]hReturn}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMghj ubh)}(h+count to be passed to read_seqcount_retry()h]h+count to be passed to read_seqcount_retry()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMghj ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j__read_seqcount_retry (C macro)c.__read_seqcount_retryhNtauh1jhjhhhNhNubj)}(hhh](j)}(h__read_seqcount_retryh]j)}(h__read_seqcount_retryh]j)}(h__read_seqcount_retryh]j)}(hjh]h__read_seqcount_retry}(hjhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjubah}(h]h ](jjeh"]h$]h&]jjuh1jhjhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubah}(h]h ]h"]h$]h&]jjjuh1jjjhjhhhjhMubah}(h]jah ](jjeh"]h$]h&]jj)jhuh1jhjhMhjhhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhjhhhjhMubeh}(h]h ](jmacroeh"]h$]h&]jjjjjjjjjuh1jhhhjhNhNubh)}(h$``__read_seqcount_retry (s, start)``h]j2)}(hjh]h __read_seqcount_retry (s, start)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjhhubj)}(h*end a seqcount_t read section w/o barrier h]h)}(h)end a seqcount_t read section w/o barrierh]h)end a seqcount_t read section w/o barrier}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMshjubah}(h]h ]h"]h$]h&]uh1jhj.hMshjhhubjK)}(hX$**Parameters** ``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants ``start`` count, from read_seqcount_begin() **Description** __read_seqcount_retry is like read_seqcount_retry, but has no smp_rmb() barrier. Callers should ensure that smp_rmb() or equivalent ordering is provided before actually loading any of the variables that are to be protected in this critical section. Use carefully, only in critical code, and comment how the barrier is provided. **Return** true if a read section retry is required, else falseh](h)}(h**Parameters**h]jU)}(hj;h]h Parameters}(hj=hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj9ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMwhj5ubjk)}(hhh](jp)}(hG``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants h](jv)}(h``s``h]j2)}(hjZh]hs}(hj\hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjXubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMthjTubj)}(hhh]h)}(h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variantsh]h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants}(hjshhhNhNubah}(h]h ]h"]h$]h&]uh1hhjohMthjpubah}(h]h ]h"]h$]h&]uh1jhjTubeh}(h]h ]h"]h$]h&]uh1johjohMthjQubjp)}(h,``start`` count, from read_seqcount_begin() h](jv)}(h ``start``h]j2)}(hjh]hstart}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMuhjubj)}(hhh]h)}(h!count, from read_seqcount_begin()h]h!count, from read_seqcount_begin()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhMuhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1johjhMuhjQubeh}(h]h ]h"]h$]h&]uh1jjhj5ubh)}(h**Description**h]jU)}(hjh]h Description}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMwhj5ubh)}(h__read_seqcount_retry is like read_seqcount_retry, but has no smp_rmb() barrier. Callers should ensure that smp_rmb() or equivalent ordering is provided before actually loading any of the variables that are to be protected in this critical section.h]h__read_seqcount_retry is like read_seqcount_retry, but has no smp_rmb() barrier. Callers should ensure that smp_rmb() or equivalent ordering is provided before actually loading any of the variables that are to be protected in this critical section.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMwhj5ubh)}(hNUse carefully, only in critical code, and comment how the barrier is provided.h]hNUse carefully, only in critical code, and comment how the barrier is provided.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM|hj5ubh)}(h **Return**h]jU)}(hjh]hReturn}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj5ubh)}(h4true if a read section retry is required, else falseh]h4true if a read section retry is required, else false}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj5ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jread_seqcount_retry (C macro)c.read_seqcount_retryhNtauh1jhjhhhNhNubj)}(hhh](j)}(hread_seqcount_retryh]j)}(hread_seqcount_retryh]j)}(hread_seqcount_retryh]j)}(hjCh]hread_seqcount_retry}(hjMhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjIubah}(h]h ](jjeh"]h$]h&]jjuh1jhjEhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubah}(h]h ]h"]h$]h&]jjjuh1jjjhjAhhhj`hMubah}(h]j<ah ](jjeh"]h$]h&]jj)jhuh1jhj`hMhj>hhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhj>hhhj`hMubeh}(h]h ](jmacroeh"]h$]h&]jjjjyjjyjjjuh1jhhhjhNhNubh)}(h"``read_seqcount_retry (s, start)``h]j2)}(hjh]hread_seqcount_retry (s, start)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj}ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjhhubj)}(h'end a seqcount_t read critical section h]h)}(h&end a seqcount_t read critical sectionh]h&end a seqcount_t read critical section}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubah}(h]h ]h"]h$]h&]uh1jhjhMhjhhubjK)}(hXw**Parameters** ``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants ``start`` count, from read_seqcount_begin() **Description** read_seqcount_retry closes the read critical section of given seqcount_t. 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If the critical section was invalid, it must be ignored (and typically retried).h]hread_seqcount_retry closes the read critical section of given seqcount_t. 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](jjeh"]h$]h&]jjuh1jhjhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubah}(h]h ]h"]h$]h&]jjjuh1jjjhjhhhjhMubah}(h]jah ](jjeh"]h$]h&]jj)jhuh1jhjhMhjhhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhjhhhjhMubeh}(h]h ](jmacroeh"]h$]h&]jjjjjjjjjuh1jhhhjhNhNubh)}(h ``raw_write_seqcount_begin (s)``h]j2)}(hjh]hraw_write_seqcount_begin (s)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjhhubj)}(h-start a seqcount_t write section w/o lockdep h]h)}(h,start a seqcount_t write section w/o lockdeph]h,start a seqcount_t write section w/o lockdep}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubah}(h]h ]h"]h$]h&]uh1jhjhMhjhhubjK)}(h**Parameters** ``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants **Context** check write_seqcount_begin()h](h)}(h**Parameters**h]jU)}(hjh]h Parameters}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubjk)}(hhh]jp)}(hG``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants h](jv)}(h``s``h]j2)}(hj=h]hs}(hj?hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj;ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj7ubj)}(hhh]h)}(h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variantsh]h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants}(hjVhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjRhMhjSubah}(h]h ]h"]h$]h&]uh1jhj7ubeh}(h]h ]h"]h$]h&]uh1johjRhMhj4ubah}(h]h ]h"]h$]h&]uh1jjhjubh)}(h **Context**h]jU)}(hjxh]hContext}(hjzhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjvubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubh)}(hcheck 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./include/linux/seqlock.hhMhjhhubj)}(h+end a seqcount_t write section w/o lockdep h]h)}(h*end a seqcount_t write section w/o lockdeph]h*end a seqcount_t write section w/o lockdep}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj ubah}(h]h ]h"]h$]h&]uh1jhjhMhjhhubjK)}(h**Parameters** ``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants **Context** check write_seqcount_end()h](h)}(h**Parameters**h]jU)}(hj(h]h Parameters}(hj*hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj&ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj"ubjk)}(hhh]jp)}(hG``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants h](jv)}(h``s``h]j2)}(hjGh]hs}(hjIhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjEubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjAubj)}(hhh]h)}(h@Pointer to seqcount_t or any of 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./include/linux/seqlock.hhMhj,ubh)}(hcheck write_seqcount_begin()h]hcheck write_seqcount_begin()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj,ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jwrite_seqcount_begin (C macro)c.write_seqcount_beginhNtauh1jhjhhhNhNubj)}(hhh](j)}(hwrite_seqcount_beginh]j)}(hwrite_seqcount_beginh]j)}(hwrite_seqcount_beginh]j)}(hj+h]hwrite_seqcount_begin}(hj5hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj1ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj-hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubah}(h]h ]h"]h$]h&]jjjuh1jjjhj)hhhjHhMubah}(h]j$ah ](jjeh"]h$]h&]jj)jhuh1jhjHhMhj&hhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhj&hhhjHhMubeh}(h]h ](jmacroeh"]h$]h&]jjjjajjajjjuh1jhhhjhNhNubh)}(h``write_seqcount_begin (s)``h]j2)}(hjgh]hwrite_seqcount_begin (s)}(hjihhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjeubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjhhubj)}(h/start a seqcount_t write side critical section h]h)}(h.start a seqcount_t write side critical sectionh]h.start a seqcount_t write side critical section}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj}ubah}(h]h ]h"]h$]h&]uh1jhjhMhjhhubjK)}(hX**Parameters** ``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants **Context** sequence counter write side sections must be serialized and non-preemptible. 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If readers can be invoked from hardirq or softirq context, interrupts or bottom halves must be respectively disabled.h](h)}(h**Parameters**h]jU)}(hjh]h Parameters}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubjk)}(hhh]jp)}(hG``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants h](jv)}(h``s``h]j2)}(hjh]hs}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubj)}(hhh]h)}(h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variantsh]h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhMhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1johjhMhjubah}(h]h ]h"]h$]h&]uh1jjhjubh)}(h **Context**h]jU)}(hjh]hContext}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubh)}(hXBsequence counter write side sections must be serialized and non-preemptible. 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If readers can be invoked from hardirq or softirq context, interrupts or bottom halves must be respectively disabled.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jwrite_seqcount_end (C macro)c.write_seqcount_endhNtauh1jhjhhhNhNubj)}(hhh](j)}(hwrite_seqcount_endh]j)}(hwrite_seqcount_endh]j)}(hwrite_seqcount_endh]j)}(hj5h]hwrite_seqcount_end}(hj?hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj;ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj7hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubah}(h]h ]h"]h$]h&]jjjuh1jjjhj3hhhjRhMubah}(h]j.ah ](jjeh"]h$]h&]jj)jhuh1jhjRhMhj0hhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhj0hhhjRhMubeh}(h]h ](jmacroeh"]h$]h&]jjjjkjjkjjjuh1jhhhjhNhNubh)}(h``write_seqcount_end (s)``h]j2)}(hjqh]hwrite_seqcount_end (s)}(hjshhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjoubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjhhubj)}(h-end a seqcount_t write side critical section h]h)}(h,end a seqcount_t write side critical sectionh]h,end a seqcount_t write side critical section}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubah}(h]h ]h"]h$]h&]uh1jhjhMhjhhubjK)}(h**Parameters** ``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants **Context** Preemption will be automatically re-enabled if and only if the seqcount write serialization lock is associated, and preemptible.h](h)}(h**Parameters**h]jU)}(hjh]h Parameters}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubjk)}(hhh]jp)}(hG``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants h](jv)}(h``s``h]j2)}(hjh]hs}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubj)}(hhh]h)}(h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variantsh]h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhMhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1johjhMhjubah}(h]h ]h"]h$]h&]uh1jjhjubh)}(h **Context**h]jU)}(hjh]hContext}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubh)}(hPreemption will be automatically re-enabled if and only if the seqcount write serialization lock is associated, and preemptible.h]hPreemption will be automatically re-enabled if and only if the seqcount write serialization lock is associated, and preemptible.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j$raw_write_seqcount_barrier (C macro)c.raw_write_seqcount_barrierhNtauh1jhjhhhNhNubj)}(hhh](j)}(hraw_write_seqcount_barrierh]j)}(hraw_write_seqcount_barrierh]j)}(hraw_write_seqcount_barrierh]j)}(hj?h]hraw_write_seqcount_barrier}(hjIhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjEubah}(h]h ](jjeh"]h$]h&]jjuh1jhjAhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM8ubah}(h]h ]h"]h$]h&]jjjuh1jjjhj=hhhj\hM8ubah}(h]j8ah ](jjeh"]h$]h&]jj)jhuh1jhj\hM8hj:hhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhj:hhhj\hM8ubeh}(h]h ](jmacroeh"]h$]h&]jjjjujjujjjuh1jhhhjhNhNubh)}(h"``raw_write_seqcount_barrier (s)``h]j2)}(hj{h]hraw_write_seqcount_barrier (s)}(hj}hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjyubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM:hjhhubj)}(hdo a seqcount_t write barrier h]h)}(hdo a seqcount_t write barrierh]hdo a seqcount_t write barrier}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubah}(h]h ]h"]h$]h&]uh1jhjhMhjhhubjK)}(hX**Parameters** ``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants **Description** This can be used to provide an ordering guarantee instead of the usual consistency guarantee. 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This is necessary because neither writes before nor after the barrier are enclosed in a seq-writer critical section that would ensure readers are aware of ongoing writes:: seqcount_t seq; bool X = true, Y = false; void read(void) { bool x, y; do { int s = read_seqcount_begin(&seq); x = X; y = Y; } while (read_seqcount_retry(&seq, s)); BUG_ON(!x && !y); } void write(void) { WRITE_ONCE(Y, true); raw_write_seqcount_barrier(seq); WRITE_ONCE(X, false); }h](h)}(h**Parameters**h]jU)}(hjh]h Parameters}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubjk)}(hhh]jp)}(hG``s`` Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants h](jv)}(h``s``h]j2)}(hjh]hs}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubj)}(hhh]h)}(h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variantsh]h@Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhMhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1johjhMhjubah}(h]h ]h"]h$]h&]uh1jjhjubh)}(h**Description**h]jU)}(hj h]h Description}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubh)}(hThis can be used to provide an ordering guarantee instead of the usual consistency guarantee. It is one wmb cheaper, because it can collapse the two back-to-back wmb()s.h]hThis can be used to provide an ordering guarantee instead of the usual consistency guarantee. It is one wmb cheaper, because it can collapse the two back-to-back wmb()s.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubh)}(hXNote that writes surrounding the barrier should be declared atomic (e.g. via WRITE_ONCE): a) to ensure the writes become visible to other threads atomically, avoiding compiler optimizations; b) to document which writes are meant to propagate to the reader critical section. 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This is necessary because neither writes before nor after the barrier are enclosed in a seq-writer critical section that would ensure readers are aware of ongoing writes:}(hj/hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubj)}(hXyseqcount_t seq; bool X = true, Y = false; void read(void) { bool x, y; do { int s = read_seqcount_begin(&seq); x = X; y = Y; } while (read_seqcount_retry(&seq, s)); BUG_ON(!x && !y); } void write(void) { WRITE_ONCE(Y, true); raw_write_seqcount_barrier(seq); WRITE_ONCE(X, false); }h]hXyseqcount_t seq; bool X = true, Y = false; void read(void) { bool x, y; do { int s = read_seqcount_begin(&seq); x = X; y = Y; } while (read_seqcount_retry(&seq, s)); BUG_ON(!x && !y); } void write(void) { WRITE_ONCE(Y, true); raw_write_seqcount_barrier(seq); WRITE_ONCE(X, false); }}hj>sbah}(h]h ]h"]h$]h&]jjuh1jhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: 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The full counter must then be checked with read_seqcount_latch_retry().h](h)}(h**Parameters**h]jU)}(hjh]h Parameters}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubjk)}(hhh]jp)}(h:``const seqcount_latch_t *s`` Pointer to seqcount_latch_t h](jv)}(h``const seqcount_latch_t *s``h]j2)}(hjh]hconst seqcount_latch_t *s}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubj)}(hhh]h)}(hPointer to seqcount_latch_th]hPointer to seqcount_latch_t}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhMhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1johjhMhjubah}(h]h ]h"]h$]h&]uh1jjhjubh)}(h**Description**h]jU)}(hj<h]h Description}(hj>hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj:ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubh)}(hNSee write_seqcount_latch() for details and a full reader/writer usage example.h]hNSee write_seqcount_latch() for details and a full reader/writer usage example.}(hjRhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubh)}(h **Return**h]jU)}(hjch]hReturn}(hjehhhNhNubah}(h]h ]h"]h$]h&]uh1jThjaubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubh)}(hsequence counter raw value. Use the lowest bit as an index for picking which data copy to read. The full counter must then be checked with read_seqcount_latch_retry().h]hsequence counter raw value. Use the lowest bit as an index for picking which data copy to read. The full counter must then be checked with read_seqcount_latch_retry().}(hjyhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j*raw_read_seqcount_latch_retry (C function)c.raw_read_seqcount_latch_retryhNtauh1jhjhhhNhNubj)}(hhh](j)}(hMint raw_read_seqcount_latch_retry (const seqcount_latch_t *s, unsigned start)h]j)}(hLint raw_read_seqcount_latch_retry(const seqcount_latch_t *s, unsigned start)h](j@)}(hinth]hint}(hjhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubjR)}(h h]h }(hjhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjhhhjhMubj)}(hraw_read_seqcount_latch_retryh]j)}(hraw_read_seqcount_latch_retryh]hraw_read_seqcount_latch_retry}(hjhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjubah}(h]h ](jjeh"]h$]h&]jjuh1jhjhhhjhMubj{)}(h+(const seqcount_latch_t *s, unsigned start)h](j)}(hconst seqcount_latch_t *sh](j)}(hjh]hconst}(hjhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjubjR)}(h h]h }(hjhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjubh)}(hhh]j)}(hseqcount_latch_th]hseqcount_latch_t}(hjhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetjmodnameN classnameNjj)}j]j)}jjsbc.raw_read_seqcount_latch_retryasbuh1hhjubjR)}(h h]h }(hj#hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjubj)}(hjh]h*}(hj1hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjubj)}(hjh]hs}(hj>hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjubj)}(hunsigned starth](j@)}(hunsignedh]hunsigned}(hjVhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjRubjR)}(h h]h }(hjdhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjRubj)}(hstarth]hstart}(hjrhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjRubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjubeh}(h]h ]h"]h$]h&]jjuh1jzhjhhhjhMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhjhhhjhMubah}(h]jah ](jjeh"]h$]h&]jj)jhuh1jhjhMhjhhubj)}(hhh]h)}(h#end a seqcount_latch_t read sectionh]h#end a seqcount_latch_t read section}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjhhubah}(h]h ]h"]h$]h&]uh1jhjhhhjhMubeh}(h]h ](jfunctioneh"]h$]h&]jjjjjjjjjuh1jhhhjhNhNubjK)}(h**Parameters** ``const seqcount_latch_t *s`` Pointer to seqcount_latch_t ``unsigned start`` count, from raw_read_seqcount_latch() **Return** true if a read section retry is required, else falseh](h)}(h**Parameters**h]jU)}(hjh]h Parameters}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubjk)}(hhh](jp)}(h:``const seqcount_latch_t *s`` Pointer to seqcount_latch_t h](jv)}(h``const seqcount_latch_t *s``h]j2)}(hjh]hconst seqcount_latch_t *s}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubj)}(hhh]h)}(hPointer to seqcount_latch_th]hPointer to seqcount_latch_t}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhMhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1johjhMhjubjp)}(h9``unsigned start`` count, from raw_read_seqcount_latch() h](jv)}(h``unsigned start``h]j2)}(hj h]hunsigned start}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj ubj)}(hhh]h)}(h%count, from raw_read_seqcount_latch()h]h%count, from raw_read_seqcount_latch()}(hj/ hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj+ hMhj, ubah}(h]h ]h"]h$]h&]uh1jhj ubeh}(h]h ]h"]h$]h&]uh1johj+ hMhjubeh}(h]h ]h"]h$]h&]uh1jjhjubh)}(h **Return**h]jU)}(hjQ h]hReturn}(hjS hhhNhNubah}(h]h ]h"]h$]h&]uh1jThjO ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubh)}(h4true if a read section retry is required, else falseh]h4true if a read section retry is required, else false}(hjg hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j&read_seqcount_latch_retry (C function)c.read_seqcount_latch_retryhNtauh1jhjhhhNhNubj)}(hhh](j)}(hIint read_seqcount_latch_retry (const seqcount_latch_t *s, unsigned start)h]j)}(hHint read_seqcount_latch_retry(const seqcount_latch_t *s, unsigned start)h](j@)}(hinth]hint}(hj hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubjR)}(h h]h }(hj hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj hhhj hMubj)}(hread_seqcount_latch_retryh]j)}(hread_seqcount_latch_retryh]hread_seqcount_latch_retry}(hj hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj hhhj hMubj{)}(h+(const seqcount_latch_t *s, unsigned start)h](j)}(hconst seqcount_latch_t *sh](j)}(hjh]hconst}(hj hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj ubjR)}(h h]h }(hj hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj ubh)}(hhh]j)}(hseqcount_latch_th]hseqcount_latch_t}(hj hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj ubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetj modnameN classnameNjj)}j]j)}jj sbc.read_seqcount_latch_retryasbuh1hhj ubjR)}(h h]h }(hj!hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj ubj)}(hjh]h*}(hj!hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj ubj)}(hjh]hs}(hj,!hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj ubj)}(hunsigned starth](j@)}(hunsignedh]hunsigned}(hjD!hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj@!ubjR)}(h h]h }(hjR!hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj@!ubj)}(hstarth]hstart}(hj`!hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj@!ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj ubeh}(h]h ]h"]h$]h&]jjuh1jzhj hhhj hMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj hhhj hMubah}(h]j ah ](jjeh"]h$]h&]jj)jhuh1jhj hMhj hhubj)}(hhh]h)}(h#end a seqcount_latch_t read sectionh]h#end a seqcount_latch_t read section}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj!hhubah}(h]h ]h"]h$]h&]uh1jhj hhhj hMubeh}(h]h ](jfunctioneh"]h$]h&]jjjj!jj!jjjuh1jhhhjhNhNubjK)}(h**Parameters** ``const seqcount_latch_t *s`` Pointer to seqcount_latch_t ``unsigned start`` count, from read_seqcount_latch() **Return** true if a read section retry is required, else falseh](h)}(h**Parameters**h]jU)}(hj!h]h Parameters}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj!ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj!ubjk)}(hhh](jp)}(h:``const seqcount_latch_t *s`` Pointer to seqcount_latch_t h](jv)}(h``const seqcount_latch_t *s``h]j2)}(hj!h]hconst seqcount_latch_t *s}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj!ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj!ubj)}(hhh]h)}(hPointer to seqcount_latch_th]hPointer to seqcount_latch_t}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj!hMhj!ubah}(h]h ]h"]h$]h&]uh1jhj!ubeh}(h]h ]h"]h$]h&]uh1johj!hMhj!ubjp)}(h5``unsigned start`` count, from read_seqcount_latch() h](jv)}(h``unsigned start``h]j2)}(hj"h]hunsigned start}(hj"hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj"ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj!ubj)}(hhh]h)}(h!count, from read_seqcount_latch()h]h!count, from read_seqcount_latch()}(hj"hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj"hMhj"ubah}(h]h ]h"]h$]h&]uh1jhj!ubeh}(h]h ]h"]h$]h&]uh1johj"hMhj!ubeh}(h]h ]h"]h$]h&]uh1jjhj!ubh)}(h **Return**h]jU)}(hj?"h]hReturn}(hjA"hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj="ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj!ubh)}(h4true if a read section retry is required, else falseh]h4true if a read section retry is required, else false}(hjU"hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj!ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j%raw_write_seqcount_latch (C function)c.raw_write_seqcount_latchhNtauh1jhjhhhNhNubj)}(hhh](j)}(h3void raw_write_seqcount_latch (seqcount_latch_t *s)h]j)}(h2void raw_write_seqcount_latch(seqcount_latch_t *s)h](j@)}(hvoidh]hvoid}(hj"hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj"hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubjR)}(h h]h }(hj"hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj"hhhj"hMubj)}(hraw_write_seqcount_latchh]j)}(hraw_write_seqcount_latchh]hraw_write_seqcount_latch}(hj"hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj"ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj"hhhj"hMubj{)}(h(seqcount_latch_t *s)h]j)}(hseqcount_latch_t *sh](h)}(hhh]j)}(hseqcount_latch_th]hseqcount_latch_t}(hj"hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj"ubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetj"modnameN classnameNjj)}j]j)}jj"sbc.raw_write_seqcount_latchasbuh1hhj"ubjR)}(h h]h }(hj"hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj"ubj)}(hjh]h*}(hj"hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj"ubj)}(hjh]hs}(hj"hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj"ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj"ubah}(h]h ]h"]h$]h&]jjuh1jzhj"hhhj"hMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj|"hhhj"hMubah}(h]jw"ah ](jjeh"]h$]h&]jj)jhuh1jhj"hMhjy"hhubj)}(hhh]h)}(h'redirect latch readers to even/odd copyh]h'redirect latch readers to even/odd copy}(hj(#hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj%#hhubah}(h]h ]h"]h$]h&]uh1jhjy"hhhj"hMubeh}(h]h ](jfunctioneh"]h$]h&]jjjj@#jj@#jjjuh1jhhhjhNhNubjK)}(hE**Parameters** ``seqcount_latch_t *s`` Pointer to seqcount_latch_th](h)}(h**Parameters**h]jU)}(hjJ#h]h Parameters}(hjL#hhhNhNubah}(h]h ]h"]h$]h&]uh1jThjH#ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjD#ubjk)}(hhh]jp)}(h3``seqcount_latch_t *s`` Pointer to seqcount_latch_th](jv)}(h``seqcount_latch_t *s``h]j2)}(hji#h]hseqcount_latch_t *s}(hjk#hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjg#ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjc#ubj)}(hhh]h)}(hPointer to seqcount_latch_th]hPointer to seqcount_latch_t}(hj#hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj#ubah}(h]h ]h"]h$]h&]uh1jhjc#ubeh}(h]h ]h"]h$]h&]uh1johj~#hMhj`#ubah}(h]h ]h"]h$]h&]uh1jjhjD#ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j'write_seqcount_latch_begin (C function)c.write_seqcount_latch_beginhNtauh1jhjhhhNhNubj)}(hhh](j)}(h5void write_seqcount_latch_begin (seqcount_latch_t *s)h]j)}(h4void write_seqcount_latch_begin(seqcount_latch_t *s)h](j@)}(hvoidh]hvoid}(hj#hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj#hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM ubjR)}(h h]h }(hj#hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj#hhhj#hM ubj)}(hwrite_seqcount_latch_beginh]j)}(hwrite_seqcount_latch_beginh]hwrite_seqcount_latch_begin}(hj#hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj#ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj#hhhj#hM ubj{)}(h(seqcount_latch_t *s)h]j)}(hseqcount_latch_t *sh](h)}(hhh]j)}(hseqcount_latch_th]hseqcount_latch_t}(hj$hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj$ubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetj$modnameN classnameNjj)}j]j)}jj#sbc.write_seqcount_latch_beginasbuh1hhj#ubjR)}(h h]h }(hj#$hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj#ubj)}(hjh]h*}(hj1$hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj#ubj)}(hjh]hs}(hj>$hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj#ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj#ubah}(h]h ]h"]h$]h&]jjuh1jzhj#hhhj#hM ubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj#hhhj#hM ubah}(h]j#ah ](jjeh"]h$]h&]jj)jhuh1jhj#hM hj#hhubj)}(hhh]h)}(h"redirect latch readers to odd copyh]h"redirect latch readers to odd copy}(hjg$hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjd$hhubah}(h]h ]h"]h$]h&]uh1jhj#hhhj#hM ubeh}(h]h ](jfunctioneh"]h$]h&]jjjj$jj$jjjuh1jhhhjhNhNubjK)}(hX **Parameters** ``seqcount_latch_t *s`` Pointer to seqcount_latch_t **Description** The latch technique is a multiversion concurrency control method that allows queries during non-atomic modifications. If you can guarantee queries never interrupt the modification -- e.g. the concurrency is strictly between CPUs -- you most likely do not need this. Where the traditional RCU/lockless data structures rely on atomic modifications to ensure queries observe either the old or the new state the latch allows the same for non-atomic updates. The trade-off is doubling the cost of storage; we have to maintain two copies of the entire data structure. Very simply put: we first modify one copy and then the other. This ensures there is always one copy in a stable state, ready to give us an answer. The basic form is a data structure like:: struct latch_struct { seqcount_latch_t seq; struct data_struct data[2]; }; Where a modification, which is assumed to be externally serialized, does the following:: void latch_modify(struct latch_struct *latch, ...) { write_seqcount_latch_begin(&latch->seq); modify(latch->data[0], ...); write_seqcount_latch(&latch->seq); modify(latch->data[1], ...); write_seqcount_latch_end(&latch->seq); } The query will have a form like:: struct entry *latch_query(struct latch_struct *latch, ...) { struct entry *entry; unsigned seq, idx; do { seq = read_seqcount_latch(&latch->seq); idx = seq & 0x01; entry = data_query(latch->data[idx], ...); // This includes needed smp_rmb() } while (read_seqcount_latch_retry(&latch->seq, seq)); return entry; } So during the modification, queries are first redirected to data[1]. Then we modify data[0]. When that is complete, we redirect queries back to data[0] and we can modify data[1]. NOTE2: When data is a dynamic data structure; one should use regular RCU patterns to manage the lifetimes of the objects within. **NOTE** The non-requirement for atomic modifications does _NOT_ include the publishing of new entries in the case where data is a dynamic data structure. An iteration might start in data[0] and get suspended long enough to miss an entire modification sequence, once it resumes it might observe the new entry.h](h)}(h**Parameters**h]jU)}(hj$h]h Parameters}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj$ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubjk)}(hhh]jp)}(h4``seqcount_latch_t *s`` Pointer to seqcount_latch_t h](jv)}(h``seqcount_latch_t *s``h]j2)}(hj$h]hseqcount_latch_t *s}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj$ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubj)}(hhh]h)}(hPointer to seqcount_latch_th]hPointer to seqcount_latch_t}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj$hMhj$ubah}(h]h ]h"]h$]h&]uh1jhj$ubeh}(h]h ]h"]h$]h&]uh1johj$hMhj$ubah}(h]h ]h"]h$]h&]uh1jjhj$ubh)}(h**Description**h]jU)}(hj$h]h Description}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj$ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubh)}(hX The latch technique is a multiversion concurrency control method that allows queries during non-atomic modifications. If you can guarantee queries never interrupt the modification -- e.g. the concurrency is strictly between CPUs -- you most likely do not need this.h]hX The latch technique is a multiversion concurrency control method that allows queries during non-atomic modifications. If you can guarantee queries never interrupt the modification -- e.g. the concurrency is strictly between CPUs -- you most likely do not need this.}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubh)}(hX'Where the traditional RCU/lockless data structures rely on atomic modifications to ensure queries observe either the old or the new state the latch allows the same for non-atomic updates. The trade-off is doubling the cost of storage; we have to maintain two copies of the entire data structure.h]hX'Where the traditional RCU/lockless data structures rely on atomic modifications to ensure queries observe either the old or the new state the latch allows the same for non-atomic updates. The trade-off is doubling the cost of storage; we have to maintain two copies of the entire data structure.}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubh)}(hVery simply put: we first modify one copy and then the other. This ensures there is always one copy in a stable state, ready to give us an answer.h]hVery simply put: we first modify one copy and then the other. This ensures there is always one copy in a stable state, ready to give us an answer.}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubh)}(h)The basic form is a data structure like::h]h(The basic form is a data structure like:}(hj&%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubj)}(hfstruct latch_struct { seqcount_latch_t seq; struct data_struct data[2]; };h]hfstruct latch_struct { seqcount_latch_t seq; struct data_struct data[2]; };}hj5%sbah}(h]h ]h"]h$]h&]jjuh1jhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubh)}(hXWhere a modification, which is assumed to be externally serialized, does the following::h]hWWhere a modification, which is assumed to be externally serialized, does the following:}(hjD%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubj)}(hX void latch_modify(struct latch_struct *latch, ...) { write_seqcount_latch_begin(&latch->seq); modify(latch->data[0], ...); write_seqcount_latch(&latch->seq); modify(latch->data[1], ...); write_seqcount_latch_end(&latch->seq); }h]hX void latch_modify(struct latch_struct *latch, ...) { write_seqcount_latch_begin(&latch->seq); modify(latch->data[0], ...); write_seqcount_latch(&latch->seq); modify(latch->data[1], ...); write_seqcount_latch_end(&latch->seq); }}hjS%sbah}(h]h ]h"]h$]h&]jjuh1jhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubh)}(h!The query will have a form like::h]h The query will have a form like:}(hjb%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubj)}(hXstruct entry *latch_query(struct latch_struct *latch, ...) { struct entry *entry; unsigned seq, idx; do { seq = read_seqcount_latch(&latch->seq); idx = seq & 0x01; entry = data_query(latch->data[idx], ...); // This includes needed smp_rmb() } while (read_seqcount_latch_retry(&latch->seq, seq)); return entry; }h]hXstruct entry *latch_query(struct latch_struct *latch, ...) { struct entry *entry; unsigned seq, idx; do { seq = read_seqcount_latch(&latch->seq); idx = seq & 0x01; entry = data_query(latch->data[idx], ...); // This includes needed smp_rmb() } while (read_seqcount_latch_retry(&latch->seq, seq)); return entry; }}hjq%sbah}(h]h ]h"]h$]h&]jjuh1jhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubh)}(hSo during the modification, queries are first redirected to data[1]. Then we modify data[0]. When that is complete, we redirect queries back to data[0] and we can modify data[1].h]hSo during the modification, queries are first redirected to data[1]. Then we modify data[0]. When that is complete, we redirect queries back to data[0] and we can modify data[1].}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubh)}(hNOTE2:h]hNOTE2:}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubj)}(hzWhen data is a dynamic data structure; one should use regular RCU patterns to manage the lifetimes of the objects within. h]h)}(hyWhen data is a dynamic data structure; one should use regular RCU patterns to manage the lifetimes of the objects within.h]hyWhen data is a dynamic data structure; one should use regular RCU patterns to manage the lifetimes of the objects within.}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj%ubah}(h]h ]h"]h$]h&]uh1jhj%hMhj$ubh)}(h**NOTE**h]jU)}(hj%h]hNOTE}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj%ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj$ubj)}(hX-The non-requirement for atomic modifications does _NOT_ include the publishing of new entries in the case where data is a dynamic data structure. An iteration might start in data[0] and get suspended long enough to miss an entire modification sequence, once it resumes it might observe the new entry.h](h)}(hThe non-requirement for atomic modifications does _NOT_ include the publishing of new entries in the case where data is a dynamic data structure.h]hThe non-requirement for atomic modifications does _NOT_ include the publishing of new entries in the case where data is a dynamic data structure.}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj%ubh)}(hAn iteration might start in data[0] and get suspended long enough to miss an entire modification sequence, once it resumes it might observe the new entry.h]hAn iteration might start in data[0] and get suspended long enough to miss an entire modification sequence, once it resumes it might observe the new entry.}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj%ubeh}(h]h ]h"]h$]h&]uh1jhj%hMhj$ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j!write_seqcount_latch (C function)c.write_seqcount_latchhNtauh1jhjhhhNhNubj)}(hhh](j)}(h/void write_seqcount_latch (seqcount_latch_t *s)h]j)}(h.void write_seqcount_latch(seqcount_latch_t *s)h](j@)}(hvoidh]hvoid}(hj&hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj&hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubjR)}(h h]h }(hj&&hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj&hhhj%&hMubj)}(hwrite_seqcount_latchh]j)}(hwrite_seqcount_latchh]hwrite_seqcount_latch}(hj8&hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj4&ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj&hhhj%&hMubj{)}(h(seqcount_latch_t *s)h]j)}(hseqcount_latch_t *sh](h)}(hhh]j)}(hseqcount_latch_th]hseqcount_latch_t}(hjW&hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjT&ubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetjY&modnameN classnameNjj)}j]j)}jj:&sbc.write_seqcount_latchasbuh1hhjP&ubjR)}(h h]h }(hjw&hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjP&ubj)}(hjh]h*}(hj&hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjP&ubj)}(hjh]hs}(hj&hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjP&ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjL&ubah}(h]h ]h"]h$]h&]jjuh1jzhj&hhhj%&hMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj&hhhj%&hMubah}(h]j &ah ](jjeh"]h$]h&]jj)jhuh1jhj%&hMhj &hhubj)}(hhh]h)}(h#redirect latch readers to even copyh]h#redirect latch readers to even copy}(hj&hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj&hhubah}(h]h ]h"]h$]h&]uh1jhj &hhhj%&hMubeh}(h]h ](jfunctioneh"]h$]h&]jjjj&jj&jjjuh1jhhhjhNhNubjK)}(hE**Parameters** ``seqcount_latch_t *s`` Pointer to seqcount_latch_th](h)}(h**Parameters**h]jU)}(hj&h]h Parameters}(hj&hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj&ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj&ubjk)}(hhh]jp)}(h3``seqcount_latch_t *s`` Pointer to seqcount_latch_th](jv)}(h``seqcount_latch_t *s``h]j2)}(hj&h]hseqcount_latch_t *s}(hj&hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj&ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj&ubj)}(hhh]h)}(hPointer to seqcount_latch_th]hPointer to seqcount_latch_t}(hj'hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj'ubah}(h]h ]h"]h$]h&]uh1jhj&ubeh}(h]h ]h"]h$]h&]uh1johj'hMhj&ubah}(h]h ]h"]h$]h&]uh1jjhj&ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j%write_seqcount_latch_end (C function)c.write_seqcount_latch_endhNtauh1jhjhhhNhNubj)}(hhh](j)}(h3void write_seqcount_latch_end (seqcount_latch_t *s)h]j)}(h2void write_seqcount_latch_end(seqcount_latch_t *s)h](j@)}(hvoidh]hvoid}(hjV'hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjR'hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM ubjR)}(h h]h }(hje'hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjR'hhhjd'hM ubj)}(hwrite_seqcount_latch_endh]j)}(hwrite_seqcount_latch_endh]hwrite_seqcount_latch_end}(hjw'hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjs'ubah}(h]h ](jjeh"]h$]h&]jjuh1jhjR'hhhjd'hM ubj{)}(h(seqcount_latch_t *s)h]j)}(hseqcount_latch_t *sh](h)}(hhh]j)}(hseqcount_latch_th]hseqcount_latch_t}(hj'hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj'ubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetj'modnameN classnameNjj)}j]j)}jjy'sbc.write_seqcount_latch_endasbuh1hhj'ubjR)}(h h]h }(hj'hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj'ubj)}(hjh]h*}(hj'hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj'ubj)}(hjh]hs}(hj'hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj'ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj'ubah}(h]h ]h"]h$]h&]jjuh1jzhjR'hhhjd'hM ubeh}(h]h ]h"]h$]h&]jjjuh1jjjhjN'hhhjd'hM ubah}(h]jI'ah ](jjeh"]h$]h&]jj)jhuh1jhjd'hM hjK'hhubj)}(hhh]h)}(h$end a seqcount_latch_t write sectionh]h$end a seqcount_latch_t write section}(hj'hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj'hhubah}(h]h ]h"]h$]h&]uh1jhjK'hhhjd'hM ubeh}(h]h ](jfunctioneh"]h$]h&]jjjj(jj(jjjuh1jhhhjhNhNubjK)}(h**Parameters** ``seqcount_latch_t *s`` Pointer to seqcount_latch_t **Description** Marks the end of a seqcount_latch_t writer section, after all copies of the latch-protected data have been updated.h](h)}(h**Parameters**h]jU)}(hj(h]h Parameters}(hj(hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj(ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj(ubjk)}(hhh]jp)}(h4``seqcount_latch_t *s`` Pointer to seqcount_latch_t h](jv)}(h``seqcount_latch_t *s``h]j2)}(hj;(h]hseqcount_latch_t *s}(hj=(hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj9(ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj5(ubj)}(hhh]h)}(hPointer to seqcount_latch_th]hPointer to seqcount_latch_t}(hjT(hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjP(hMhjQ(ubah}(h]h ]h"]h$]h&]uh1jhj5(ubeh}(h]h ]h"]h$]h&]uh1johjP(hMhj2(ubah}(h]h ]h"]h$]h&]uh1jjhj(ubh)}(h**Description**h]jU)}(hjv(h]h Description}(hjx(hhhNhNubah}(h]h ]h"]h$]h&]uh1jThjt(ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj(ubh)}(hsMarks the end of a seqcount_latch_t writer section, after all copies of the latch-protected data have been updated.h]hsMarks the end of a seqcount_latch_t writer section, after all copies of the latch-protected data have been updated.}(hj(hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj(ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jseqlock_init (C macro)c.seqlock_inithNtauh1jhjhhhNhNubj)}(hhh](j)}(h seqlock_inith]j)}(h seqlock_inith]j)}(h seqlock_inith]j)}(hj(h]h seqlock_init}(hj(hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj(ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj(hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM/ubah}(h]h ]h"]h$]h&]jjjuh1jjjhj(hhhj(hM/ubah}(h]j(ah ](jjeh"]h$]h&]jj)jhuh1jhj(hM/hj(hhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhj(hhhj(hM/ubeh}(h]h ](jmacroeh"]h$]h&]jjjj(jj(jjjuh1jhhhjhNhNubh)}(h``seqlock_init (sl)``h]j2)}(hj(h]hseqlock_init (sl)}(hj(hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj(ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM1hjhhubj)}(h"dynamic initializer for seqlock_t h]h)}(h!dynamic initializer for seqlock_th]h!dynamic initializer for seqlock_t}(hj )hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM,hj)ubah}(h]h ]h"]h$]h&]uh1jhj)hM,hjhhubjK)}(h:**Parameters** ``sl`` Pointer to the seqlock_t instanceh](h)}(h**Parameters**h]jU)}(hj&)h]h Parameters}(hj()hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj$)ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM0hj )ubjk)}(hhh]jp)}(h(``sl`` Pointer to the seqlock_t instanceh](jv)}(h``sl``h]j2)}(hjE)h]hsl}(hjG)hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjC)ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM2hj?)ubj)}(hhh]h)}(h!Pointer to the seqlock_t instanceh]h!Pointer to the seqlock_t instance}(hj^)hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM-hj[)ubah}(h]h ]h"]h$]h&]uh1jhj?)ubeh}(h]h ]h"]h$]h&]uh1johjZ)hM2hj<)ubah}(h]h ]h"]h$]h&]uh1jjhj )ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jDEFINE_SEQLOCK (C macro)c.DEFINE_SEQLOCKhNtauh1jhjhhhNhNubj)}(hhh](j)}(hDEFINE_SEQLOCKh]j)}(hDEFINE_SEQLOCKh]j)}(hDEFINE_SEQLOCKh]j)}(hj)h]hDEFINE_SEQLOCK}(hj)hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj)ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj)hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM9ubah}(h]h ]h"]h$]h&]jjjuh1jjjhj)hhhj)hM9ubah}(h]j)ah ](jjeh"]h$]h&]jj)jhuh1jhj)hM9hj)hhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhj)hhhj)hM9ubeh}(h]h ](jmacroeh"]h$]h&]jjjj)jj)jjjuh1jhhhjhNhNubh)}(h``DEFINE_SEQLOCK (sl)``h]j2)}(hj)h]hDEFINE_SEQLOCK (sl)}(hj)hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj)ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM;hjhhubj)}(h(Define a statically allocated seqlock_t h]h)}(h'Define a statically allocated seqlock_th]h'Define a statically allocated seqlock_t}(hj)hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM6hj)ubah}(h]h ]h"]h$]h&]uh1jhj)hM6hjhhubjK)}(h7**Parameters** ``sl`` Name of the seqlock_t instanceh](h)}(h**Parameters**h]jU)}(hj *h]h Parameters}(hj *hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj*ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM:hj*ubjk)}(hhh]jp)}(h%``sl`` Name of the seqlock_t instanceh](jv)}(h``sl``h]j2)}(hj)*h]hsl}(hj+*hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj'*ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM<hj#*ubj)}(hhh]h)}(hName of the seqlock_t instanceh]hName of the seqlock_t instance}(hjB*hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM7hj?*ubah}(h]h ]h"]h$]h&]uh1jhj#*ubeh}(h]h ]h"]h$]h&]uh1johj>*hM<hj *ubah}(h]h ]h"]h$]h&]uh1jjhj*ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jread_seqbegin (C function)c.read_seqbeginhNtauh1jhjhhhNhNubj)}(hhh](j)}(h,unsigned read_seqbegin (const seqlock_t *sl)h]j)}(h+unsigned read_seqbegin(const seqlock_t *sl)h](j@)}(hunsignedh]hunsigned}(hj*hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj*hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMBubjR)}(h h]h }(hj*hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj*hhhj*hMBubj)}(h read_seqbeginh]j)}(h read_seqbeginh]h read_seqbegin}(hj*hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj*ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj*hhhj*hMBubj{)}(h(const seqlock_t *sl)h]j)}(hconst seqlock_t *slh](j)}(hjh]hconst}(hj*hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj*ubjR)}(h h]h }(hj*hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj*ubh)}(hhh]j)}(h seqlock_th]h seqlock_t}(hj*hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj*ubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetj*modnameN classnameNjj)}j]j)}jj*sbc.read_seqbeginasbuh1hhj*ubjR)}(h h]h }(hj*hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj*ubj)}(hjh]h*}(hj +hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj*ubj)}(hslh]hsl}(hj+hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj*ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj*ubah}(h]h ]h"]h$]h&]jjuh1jzhj*hhhj*hMBubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj{*hhhj*hMBubah}(h]jv*ah ](jjeh"]h$]h&]jj)jhuh1jhj*hMBhjx*hhubj)}(hhh]h)}(h,start a seqlock_t read side critical sectionh]h,start a seqlock_t read side critical section}(hjC+hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM=hj@+hhubah}(h]h ]h"]h$]h&]uh1jhjx*hhhj*hMBubeh}(h]h ](jfunctioneh"]h$]h&]jjjj[+jj[+jjjuh1jhhhjhNhNubjK)}(hr**Parameters** ``const seqlock_t *sl`` Pointer to seqlock_t **Return** count, to be passed to read_seqretry()h](h)}(h**Parameters**h]jU)}(hje+h]h Parameters}(hjg+hhhNhNubah}(h]h ]h"]h$]h&]uh1jThjc+ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMAhj_+ubjk)}(hhh]jp)}(h-``const seqlock_t *sl`` Pointer to seqlock_t h](jv)}(h``const seqlock_t *sl``h]j2)}(hj+h]hconst seqlock_t *sl}(hj+hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj+ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM>hj~+ubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hj+hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj+hM>hj+ubah}(h]h ]h"]h$]h&]uh1jhj~+ubeh}(h]h ]h"]h$]h&]uh1johj+hM>hj{+ubah}(h]h ]h"]h$]h&]uh1jjhj_+ubh)}(h **Return**h]jU)}(hj+h]hReturn}(hj+hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj+ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM@hj_+ubh)}(h&count, to be passed to read_seqretry()h]h&count, to be passed to read_seqretry()}(hj+hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM@hj_+ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jread_seqretry (C function)c.read_seqretryhNtauh1jhjhhhNhNubj)}(hhh](j)}(h6hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj:6hMhj;6ubah}(h]h ]h"]h$]h&]uh1jhj6ubeh}(h]h ]h"]h$]h&]uh1johj:6hMhj6ubah}(h]h ]h"]h$]h&]uh1jjhj6ubh)}(h**Description**h]jU)}(hj`6h]h Description}(hjb6hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj^6ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj6ubh)}(h}write_sequnlock_irq closes the serialized and non-interruptible seqlock_t write side section opened with write_seqlock_irq().h]h}write_sequnlock_irq closes the serialized and non-interruptible seqlock_t write side section opened with write_seqlock_irq().}(hjv6hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj6ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jwrite_seqlock_irqsave (C macro)c.write_seqlock_irqsavehNtauh1jhjhhhNhNubj)}(hhh](j)}(hwrite_seqlock_irqsaveh]j)}(hwrite_seqlock_irqsaveh]j)}(hwrite_seqlock_irqsaveh]j)}(hj6h]hwrite_seqlock_irqsave}(hj6hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj6ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj6hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubah}(h]h ]h"]h$]h&]jjjuh1jjjhj6hhhj6hMubah}(h]j6ah ](jjeh"]h$]h&]jj)jhuh1jhj6hMhj6hhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhj6hhhj6hMubeh}(h]h ](jmacroeh"]h$]h&]jjjj6jj6jjjuh1jhhhjhNhNubh)}(h'``write_seqlock_irqsave (lock, flags)``h]j2)}(hj6h]h#write_seqlock_irqsave (lock, flags)}(hj6hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj6ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjhhubj)}(h2start a non-interruptible seqlock_t write section h]h)}(h1start a non-interruptible seqlock_t write sectionh]h1start a non-interruptible seqlock_t write section}(hj6hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj6ubah}(h]h ]h"]h$]h&]uh1jhj7hMhjhhubjK)}(hXJ**Parameters** ``lock`` Pointer to seqlock_t ``flags`` Stack-allocated storage for saving caller's local interrupt state, to be passed to write_sequnlock_irqrestore(). **Description** _irqsave variant of write_seqlock(). Use it only if the read side section, or other write sections, can be invoked from hardirq context.h](h)}(h**Parameters**h]jU)}(hj7h]h Parameters}(hj7hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj7ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj 7ubjk)}(hhh](jp)}(h``lock`` Pointer to seqlock_t h](jv)}(h``lock``h]j2)}(hj/7h]hlock}(hj17hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj-7ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj)7ubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hjH7hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjD7hMhjE7ubah}(h]h ]h"]h$]h&]uh1jhj)7ubeh}(h]h ]h"]h$]h&]uh1johjD7hMhj&7ubjp)}(h{``flags`` Stack-allocated storage for saving caller's local interrupt state, to be passed to write_sequnlock_irqrestore(). h](jv)}(h ``flags``h]j2)}(hjh7h]hflags}(hjj7hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjf7ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjb7ubj)}(hhh]h)}(hpStack-allocated storage for saving caller's local interrupt state, to be passed to write_sequnlock_irqrestore().h]hrStack-allocated storage for saving caller’s local interrupt state, to be passed to write_sequnlock_irqrestore().}(hj7hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj~7ubah}(h]h ]h"]h$]h&]uh1jhjb7ubeh}(h]h ]h"]h$]h&]uh1johj}7hMhj&7ubeh}(h]h ]h"]h$]h&]uh1jjhj 7ubh)}(h**Description**h]jU)}(hj7h]h Description}(hj7hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj7ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj 7ubh)}(h_irqsave variant of write_seqlock(). Use it only if the read side section, or other write sections, can be invoked from hardirq context.h]h_irqsave variant of write_seqlock(). Use it only if the read side section, or other write sections, can be invoked from hardirq context.}(hj7hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj 7ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j'write_sequnlock_irqrestore (C function)c.write_sequnlock_irqrestorehNtauh1jhjhhhNhNubj)}(hhh](j)}(hDvoid write_sequnlock_irqrestore (seqlock_t *sl, unsigned long flags)h]j)}(hCvoid write_sequnlock_irqrestore(seqlock_t *sl, unsigned long flags)h](j@)}(hvoidh]hvoid}(hj7hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj7hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubjR)}(h h]h }(hj7hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj7hhhj7hMubj)}(hwrite_sequnlock_irqrestoreh]j)}(hwrite_sequnlock_irqrestoreh]hwrite_sequnlock_irqrestore}(hj 8hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj8ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj7hhhj7hMubj{)}(h$(seqlock_t *sl, unsigned long flags)h](j)}(h seqlock_t *slh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hj)8hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj&8ubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetj+8modnameN classnameNjj)}j]j)}jj 8sbc.write_sequnlock_irqrestoreasbuh1hhj"8ubjR)}(h h]h }(hjI8hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj"8ubj)}(hjh]h*}(hjW8hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj"8ubj)}(hslh]hsl}(hjd8hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj"8ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj8ubj)}(hunsigned long flagsh](j@)}(hunsignedh]hunsigned}(hj}8hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjy8ubjR)}(h h]h }(hj8hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjy8ubj@)}(hlongh]hlong}(hj8hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjy8ubjR)}(h h]h }(hj8hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjy8ubj)}(hflagsh]hflags}(hj8hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjy8ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj8ubeh}(h]h ]h"]h$]h&]jjuh1jzhj7hhhj7hMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj7hhhj7hMubah}(h]j7ah ](jjeh"]h$]h&]jj)jhuh1jhj7hMhj7hhubj)}(hhh]h)}(h-end non-interruptible seqlock_t write sectionh]h-end non-interruptible seqlock_t write section}(hj8hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj8hhubah}(h]h ]h"]h$]h&]uh1jhj7hhhj7hMubeh}(h]h ](jfunctioneh"]h$]h&]jjjj8jj8jjjuh1jhhhjhNhNubjK)}(hX1**Parameters** ``seqlock_t *sl`` Pointer to seqlock_t ``unsigned long flags`` Caller's saved interrupt state, from write_seqlock_irqsave() **Description** write_sequnlock_irqrestore closes the serialized and non-interruptible seqlock_t write section previously opened with write_seqlock_irqsave().h](h)}(h**Parameters**h]jU)}(hj9h]h Parameters}(hj9hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj8ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj8ubjk)}(hhh](jp)}(h'``seqlock_t *sl`` Pointer to seqlock_t h](jv)}(h``seqlock_t *sl``h]j2)}(hj 9h]h seqlock_t *sl}(hj"9hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj9ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj9ubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hj99hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj59hMhj69ubah}(h]h ]h"]h$]h&]uh1jhj9ubeh}(h]h ]h"]h$]h&]uh1johj59hMhj9ubjp)}(hU``unsigned long flags`` Caller's saved interrupt state, from write_seqlock_irqsave() h](jv)}(h``unsigned long flags``h]j2)}(hjY9h]hunsigned long flags}(hj[9hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjW9ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjS9ubj)}(hhh]h)}(hCaller’s saved interrupt state, from write_seqlock_irqsave()}(hjr9hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjn9hMhjo9ubah}(h]h ]h"]h$]h&]uh1jhjS9ubeh}(h]h ]h"]h$]h&]uh1johjn9hMhj9ubeh}(h]h ]h"]h$]h&]uh1jjhj8ubh)}(h**Description**h]jU)}(hj9h]h Description}(hj9hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj9ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj8ubh)}(hwrite_sequnlock_irqrestore closes the serialized and non-interruptible seqlock_t write section previously opened with write_seqlock_irqsave().h]hwrite_sequnlock_irqrestore closes the serialized and non-interruptible seqlock_t write section previously opened with write_seqlock_irqsave().}(hj9hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj8ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jread_seqlock_excl (C function)c.read_seqlock_exclhNtauh1jhjhhhNhNubj)}(hhh](j)}(h&void read_seqlock_excl (seqlock_t *sl)h]j)}(h%void read_seqlock_excl(seqlock_t *sl)h](j@)}(hvoidh]hvoid}(hj9hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj9hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubjR)}(h h]h }(hj9hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj9hhhj9hMubj)}(hread_seqlock_exclh]j)}(hread_seqlock_exclh]hread_seqlock_excl}(hj9hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj9ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj9hhhj9hMubj{)}(h(seqlock_t *sl)h]j)}(h seqlock_t *slh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hj:hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj:ubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetj:modnameN classnameNjj)}j]j)}jj9sbc.read_seqlock_exclasbuh1hhj:ubjR)}(h h]h }(hj9:hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj:ubj)}(hjh]h*}(hjG:hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj:ubj)}(hslh]hsl}(hjT:hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj:ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj:ubah}(h]h ]h"]h$]h&]jjuh1jzhj9hhhj9hMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj9hhhj9hMubah}(h]j9ah ](jjeh"]h$]h&]jj)jhuh1jhj9hMhj9hhubj)}(hhh]h)}(h(begin a seqlock_t locking reader sectionh]h(begin a seqlock_t locking reader section}(hj~:hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj{:hhubah}(h]h ]h"]h$]h&]uh1jhj9hhhj9hMubeh}(h]h ](jfunctioneh"]h$]h&]jjjj:jj:jjjuh1jhhhjhNhNubjK)}(hXS**Parameters** ``seqlock_t *sl`` Pointer to seqlock_t **Description** read_seqlock_excl opens a seqlock_t locking reader critical section. A locking reader exclusively locks out *both* other writers *and* other locking readers, but it does not update the embedded sequence number. Locking readers act like a normal spin_lock()/spin_unlock(). The opened read section must be closed with read_sequnlock_excl(). **Context** if the seqlock_t write section, *or other read sections*, can be invoked from hardirq or softirq contexts, use the _irqsave or _bh variant of this function instead.h](h)}(h**Parameters**h]jU)}(hj:h]h Parameters}(hj:hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj:ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj:ubjk)}(hhh]jp)}(h'``seqlock_t *sl`` Pointer to seqlock_t h](jv)}(h``seqlock_t *sl``h]j2)}(hj:h]h seqlock_t *sl}(hj:hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj:ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj:ubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hj:hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj:hMhj:ubah}(h]h ]h"]h$]h&]uh1jhj:ubeh}(h]h ]h"]h$]h&]uh1johj:hMhj:ubah}(h]h ]h"]h$]h&]uh1jjhj:ubh)}(h**Description**h]jU)}(hj:h]h Description}(hj:hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj:ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj:ubh)}(hread_seqlock_excl opens a seqlock_t locking reader critical section. A locking reader exclusively locks out *both* other writers *and* other locking readers, but it does not update the embedded sequence number.h](hmread_seqlock_excl opens a seqlock_t locking reader critical section. A locking reader exclusively locks out }(hj;hhhNhNubhemphasis)}(h*both*h]hboth}(hj;hhhNhNubah}(h]h ]h"]h$]h&]uh1j;hj;ubh other writers }(hj;hhhNhNubj;)}(h*and*h]hand}(hj,;hhhNhNubah}(h]h ]h"]h$]h&]uh1j;hj;ubhL other locking readers, but it does not update the embedded sequence number.}(hj;hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj:ubh)}(h=modnameN classnameNjj)}j]j)}jj=sbc.read_seqlock_excl_bhasbuh1hhj5=ubjR)}(h h]h }(hj\=hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj5=ubj)}(hjh]h*}(hjj=hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj5=ubj)}(hslh]hsl}(hjw=hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj5=ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj1=ubah}(h]h ]h"]h$]h&]jjuh1jzhj<hhhj =hMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj<hhhj =hMubah}(h]j<ah ](jjeh"]h$]h&]jj)jhuh1jhj =hMhj<hhubj)}(hhh]h)}(h?start a seqlock_t locking reader section with softirqs disabledh]h?start a seqlock_t locking reader section with softirqs disabled}(hj=hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj=hhubah}(h]h ]h"]h$]h&]uh1jhj<hhhj =hMubeh}(h]h ](jfunctioneh"]h$]h&]jjjj=jj=jjjuh1jhhhjhNhNubjK)}(h**Parameters** ``seqlock_t *sl`` Pointer to seqlock_t **Description** _bh variant of read_seqlock_excl(). Use this variant only if the seqlock_t write side section, *or other read sections*, can be invoked from softirq contexts.h](h)}(h**Parameters**h]jU)}(hj=h]h Parameters}(hj=hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj=ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj=ubjk)}(hhh]jp)}(h'``seqlock_t *sl`` Pointer to seqlock_t h](jv)}(h``seqlock_t *sl``h]j2)}(hj=h]h seqlock_t *sl}(hj=hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj=ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj=ubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hj=hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj=hMhj=ubah}(h]h ]h"]h$]h&]uh1jhj=ubeh}(h]h ]h"]h$]h&]uh1johj=hMhj=ubah}(h]h ]h"]h$]h&]uh1jjhj=ubh)}(h**Description**h]jU)}(hj>h]h Description}(hj>hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj>ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj=ubh)}(h_bh variant of read_seqlock_excl(). Use this variant only if the seqlock_t write side section, *or other read sections*, can be invoked from softirq contexts.h](h__bh variant of read_seqlock_excl(). Use this variant only if the seqlock_t write side section, }(hj3>hhhNhNubj;)}(h*or other read sections*h]hor other read sections}(hj;>hhhNhNubah}(h]h ]h"]h$]h&]uh1j;hj3>ubh', can be invoked from softirq contexts.}(hj3>hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj=ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j#read_sequnlock_excl_bh (C function)c.read_sequnlock_excl_bhhNtauh1jhjhhhNhNubj)}(hhh](j)}(h+void read_sequnlock_excl_bh (seqlock_t *sl)h]j)}(h*void read_sequnlock_excl_bh(seqlock_t *sl)h](j@)}(hvoidh]hvoid}(hjt>hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjp>hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM ubjR)}(h h]h }(hj>hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjp>hhhj>hM ubj)}(hread_sequnlock_excl_bhh]j)}(hread_sequnlock_excl_bhh]hread_sequnlock_excl_bh}(hj>hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj>ubah}(h]h ](jjeh"]h$]h&]jjuh1jhjp>hhhj>hM ubj{)}(h(seqlock_t *sl)h]j)}(h seqlock_t *slh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hj>hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj>ubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetj>modnameN classnameNjj)}j]j)}jj>sbc.read_sequnlock_excl_bhasbuh1hhj>ubjR)}(h h]h }(hj>hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj>ubj)}(hjh]h*}(hj>hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj>ubj)}(hslh]hsl}(hj>hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj>ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj>ubah}(h]h ]h"]h$]h&]jjuh1jzhjp>hhhj>hM ubeh}(h]h ]h"]h$]h&]jjjuh1jjjhjl>hhhj>hM ubah}(h]jg>ah ](jjeh"]h$]h&]jj)jhuh1jhj>hM hji>hhubj)}(hhh]h)}(h8stop a seqlock_t softirq-disabled locking reader sectionh]h8stop a seqlock_t softirq-disabled locking reader section}(hj?hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj?hhubah}(h]h ]h"]h$]h&]uh1jhji>hhhj>hM ubeh}(h]h ](jfunctioneh"]h$]h&]jjjj1?jj1?jjjuh1jhhhjhNhNubjK)}(h8**Parameters** ``seqlock_t *sl`` Pointer to seqlock_th](h)}(h**Parameters**h]jU)}(hj;?h]h Parameters}(hj=?hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj9?ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM hj5?ubjk)}(hhh]jp)}(h&``seqlock_t *sl`` Pointer to seqlock_th](jv)}(h``seqlock_t *sl``h]j2)}(hjZ?h]h seqlock_t *sl}(hj\?hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjX?ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM hjT?ubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hjs?hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjp?ubah}(h]h ]h"]h$]h&]uh1jhjT?ubeh}(h]h ]h"]h$]h&]uh1johjo?hM hjQ?ubah}(h]h ]h"]h$]h&]uh1jjhj5?ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j"read_seqlock_excl_irq (C function)c.read_seqlock_excl_irqhNtauh1jhjhhhNhNubj)}(hhh](j)}(h*void read_seqlock_excl_irq (seqlock_t *sl)h]j)}(h)void read_seqlock_excl_irq(seqlock_t *sl)h](j@)}(hvoidh]hvoid}(hj?hhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj?hhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubjR)}(h h]h }(hj?hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj?hhhj?hMubj)}(hread_seqlock_excl_irqh]j)}(hread_seqlock_excl_irqh]hread_seqlock_excl_irq}(hj?hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj?ubah}(h]h ](jjeh"]h$]h&]jjuh1jhj?hhhj?hMubj{)}(h(seqlock_t *sl)h]j)}(h seqlock_t *slh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hj?hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj?ubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetj?modnameN classnameNjj)}j]j)}jj?sbc.read_seqlock_excl_irqasbuh1hhj?ubjR)}(h h]h }(hj@hhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj?ubj)}(hjh]h*}(hj"@hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj?ubj)}(hslh]hsl}(hj/@hhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj?ubeh}(h]h ]h"]h$]h&]noemphjjuh1jhj?ubah}(h]h ]h"]h$]h&]jjuh1jzhj?hhhj?hMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj?hhhj?hMubah}(h]j?ah ](jjeh"]h$]h&]jj)jhuh1jhj?hMhj?hhubj)}(hhh]h)}(h:start a non-interruptible seqlock_t locking reader sectionh]h:start a non-interruptible seqlock_t locking reader section}(hjY@hhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjV@hhubah}(h]h ]h"]h$]h&]uh1jhj?hhhj?hMubeh}(h]h ](jfunctioneh"]h$]h&]jjjjq@jjq@jjjuh1jhhhjhNhNubjK)}(h**Parameters** ``seqlock_t *sl`` Pointer to seqlock_t **Description** _irq variant of read_seqlock_excl(). Use this only if the seqlock_t write side section, *or other read sections*, can be invoked from a hardirq context.h](h)}(h**Parameters**h]jU)}(hj{@h]h Parameters}(hj}@hhhNhNubah}(h]h ]h"]h$]h&]uh1jThjy@ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhju@ubjk)}(hhh]jp)}(h'``seqlock_t *sl`` Pointer to seqlock_t h](jv)}(h``seqlock_t *sl``h]j2)}(hj@h]h seqlock_t *sl}(hj@hhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj@ubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj@ubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hj@hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj@hMhj@ubah}(h]h ]h"]h$]h&]uh1jhj@ubeh}(h]h ]h"]h$]h&]uh1johj@hMhj@ubah}(h]h ]h"]h$]h&]uh1jjhju@ubh)}(h**Description**h]jU)}(hj@h]h Description}(hj@hhhNhNubah}(h]h ]h"]h$]h&]uh1jThj@ubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhju@ubh)}(h_irq variant of read_seqlock_excl(). Use this only if the seqlock_t write side section, *or other read sections*, can be invoked from a hardirq context.h](hX_irq variant of read_seqlock_excl(). Use this only if the seqlock_t write side section, }(hj@hhhNhNubj;)}(h*or other read sections*h]hor other read sections}(hj@hhhNhNubah}(h]h ]h"]h$]h&]uh1j;hj@ubh(, can be invoked from a hardirq context.}(hj@hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhju@ubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j$read_sequnlock_excl_irq (C function)c.read_sequnlock_excl_irqhNtauh1jhjhhhNhNubj)}(hhh](j)}(h,void read_sequnlock_excl_irq (seqlock_t *sl)h]j)}(h+void read_sequnlock_excl_irq(seqlock_t *sl)h](j@)}(hvoidh]hvoid}(hj,AhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj(AhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM!ubjR)}(h h]h }(hj;AhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj(Ahhhj:AhM!ubj)}(hread_sequnlock_excl_irqh]j)}(hread_sequnlock_excl_irqh]hread_sequnlock_excl_irq}(hjMAhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjIAubah}(h]h ](jjeh"]h$]h&]jjuh1jhj(Ahhhj:AhM!ubj{)}(h(seqlock_t *sl)h]j)}(h seqlock_t *slh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hjlAhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjiAubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetjnAmodnameN classnameNjj)}j]j)}jjOAsbc.read_sequnlock_excl_irqasbuh1hhjeAubjR)}(h h]h }(hjAhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjeAubj)}(hjh]h*}(hjAhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjeAubj)}(hslh]hsl}(hjAhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjeAubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjaAubah}(h]h ]h"]h$]h&]jjuh1jzhj(Ahhhj:AhM!ubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj$Ahhhj:AhM!ubah}(h]jAah ](jjeh"]h$]h&]jj)jhuh1jhj:AhM!hj!Ahhubj)}(hhh]h)}(h;end an interrupts-disabled seqlock_t locking reader sectionh]h;end an interrupts-disabled seqlock_t locking reader section}(hjAhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjAhhubah}(h]h ]h"]h$]h&]uh1jhj!Ahhhj:AhM!ubeh}(h]h ](jfunctioneh"]h$]h&]jjjjAjjAjjjuh1jhhhjhNhNubjK)}(h8**Parameters** ``seqlock_t *sl`` Pointer to seqlock_th](h)}(h**Parameters**h]jU)}(hjAh]h Parameters}(hjAhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjAubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM!hjAubjk)}(hhh]jp)}(h&``seqlock_t *sl`` Pointer to seqlock_th](jv)}(h``seqlock_t *sl``h]j2)}(hjBh]h seqlock_t *sl}(hjBhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjBubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM#hj Bubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hj+BhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj(Bubah}(h]h ]h"]h$]h&]uh1jhj Bubeh}(h]h ]h"]h$]h&]uh1johj'BhM#hj Bubah}(h]h ]h"]h$]h&]uh1jjhjAubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j#read_seqlock_excl_irqsave (C macro)c.read_seqlock_excl_irqsavehNtauh1jhjhhhNhNubj)}(hhh](j)}(hread_seqlock_excl_irqsaveh]j)}(hread_seqlock_excl_irqsaveh]j)}(hread_seqlock_excl_irqsaveh]j)}(hjfBh]hread_seqlock_excl_irqsave}(hjpBhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjlBubah}(h]h ](jjeh"]h$]h&]jjuh1jhjhBhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM9ubah}(h]h ]h"]h$]h&]jjjuh1jjjhjdBhhhjBhM9ubah}(h]j_Bah ](jjeh"]h$]h&]jj)jhuh1jhjBhM9hjaBhhubj)}(hhh]h}(h]h ]h"]h$]h&]uh1jhjaBhhhjBhM9ubeh}(h]h ](jmacroeh"]h$]h&]jjjjBjjBjjjuh1jhhhjhNhNubh)}(h+``read_seqlock_excl_irqsave (lock, flags)``h]j2)}(hjBh]h'read_seqlock_excl_irqsave (lock, flags)}(hjBhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjBubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM;hjhhubj)}(h;start a non-interruptible seqlock_t locking reader section h]h)}(h:start a non-interruptible seqlock_t locking reader sectionh]h:start a non-interruptible seqlock_t locking reader section}(hjBhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM/hjBubah}(h]h ]h"]h$]h&]uh1jhjBhM/hjhhubjK)}(hXb**Parameters** ``lock`` Pointer to seqlock_t ``flags`` Stack-allocated storage for saving caller's local interrupt state, to be passed to read_sequnlock_excl_irqrestore(). **Description** _irqsave variant of read_seqlock_excl(). Use this only if the seqlock_t write side section, *or other read sections*, can be invoked from a hardirq context.h](h)}(h**Parameters**h]jU)}(hjBh]h Parameters}(hjBhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjBubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM3hjBubjk)}(hhh](jp)}(h``lock`` Pointer to seqlock_t h](jv)}(h``lock``h]j2)}(hjBh]hlock}(hjBhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjBubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM1hjBubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hjChhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ChM1hj Cubah}(h]h ]h"]h$]h&]uh1jhjBubeh}(h]h ]h"]h$]h&]uh1johj ChM1hjBubjp)}(h``flags`` Stack-allocated storage for saving caller's local interrupt state, to be passed to read_sequnlock_excl_irqrestore(). h](jv)}(h ``flags``h]j2)}(hj/Ch]hflags}(hj1ChhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj-Cubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM3hj)Cubj)}(hhh]h)}(htStack-allocated storage for saving caller's local interrupt state, to be passed to read_sequnlock_excl_irqrestore().h]hvStack-allocated storage for saving caller’s local interrupt state, to be passed to read_sequnlock_excl_irqrestore().}(hjHChhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM2hjECubah}(h]h ]h"]h$]h&]uh1jhj)Cubeh}(h]h ]h"]h$]h&]uh1johjDChM3hjBubeh}(h]h ]h"]h$]h&]uh1jjhjBubh)}(h**Description**h]jU)}(hjkCh]h Description}(hjmChhhNhNubah}(h]h ]h"]h$]h&]uh1jThjiCubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM5hjBubh)}(h_irqsave variant of read_seqlock_excl(). Use this only if the seqlock_t write side section, *or other read sections*, can be invoked from a hardirq context.h](h\_irqsave variant of read_seqlock_excl(). Use this only if the seqlock_t write side section, }(hjChhhNhNubj;)}(h*or other read sections*h]hor other read sections}(hjChhhNhNubah}(h]h ]h"]h$]h&]uh1j;hjCubh(, can be invoked from a hardirq context.}(hjChhhNhNubeh}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM5hjBubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j+read_sequnlock_excl_irqrestore (C function) c.read_sequnlock_excl_irqrestorehNtauh1jhjhhhNhNubj)}(hhh](j)}(hHvoid read_sequnlock_excl_irqrestore (seqlock_t *sl, unsigned long flags)h]j)}(hGvoid read_sequnlock_excl_irqrestore(seqlock_t *sl, unsigned long flags)h](j@)}(hvoidh]hvoid}(hjChhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjChhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMBubjR)}(h h]h }(hjChhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjChhhjChMBubj)}(hread_sequnlock_excl_irqrestoreh]j)}(hread_sequnlock_excl_irqrestoreh]hread_sequnlock_excl_irqrestore}(hjChhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjCubah}(h]h ](jjeh"]h$]h&]jjuh1jhjChhhjChMBubj{)}(h$(seqlock_t *sl, unsigned long flags)h](j)}(h seqlock_t *slh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hjDhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjCubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetjDmodnameN classnameNjj)}j]j)}jjCsb c.read_sequnlock_excl_irqrestoreasbuh1hhjCubjR)}(h h]h }(hj"DhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjCubj)}(hjh]h*}(hj0DhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjCubj)}(hslh]hsl}(hj=DhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjCubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjCubj)}(hunsigned long flagsh](j@)}(hunsignedh]hunsigned}(hjVDhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjRDubjR)}(h h]h }(hjdDhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjRDubj@)}(hlongh]hlong}(hjrDhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjRDubjR)}(h h]h }(hjDhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjRDubj)}(hflagsh]hflags}(hjDhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjRDubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjCubeh}(h]h ]h"]h$]h&]jjuh1jzhjChhhjChMBubeh}(h]h ]h"]h$]h&]jjjuh1jjjhjChhhjChMBubah}(h]jCah ](jjeh"]h$]h&]jj)jhuh1jhjChMBhjChhubj)}(hhh]h)}(h6end non-interruptible seqlock_t locking reader sectionh]h6end non-interruptible seqlock_t locking reader section}(hjDhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM=hjDhhubah}(h]h ]h"]h$]h&]uh1jhjChhhjChMBubeh}(h]h ](jfunctioneh"]h$]h&]jjjjDjjDjjjuh1jhhhjhNhNubjK)}(h**Parameters** ``seqlock_t *sl`` Pointer to seqlock_t ``unsigned long flags`` Caller saved interrupt state, from read_seqlock_excl_irqsave()h](h)}(h**Parameters**h]jU)}(hjDh]h Parameters}(hjDhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjDubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMAhjDubjk)}(hhh](jp)}(h'``seqlock_t *sl`` Pointer to seqlock_t h](jv)}(h``seqlock_t *sl``h]j2)}(hjDh]h seqlock_t *sl}(hjDhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjDubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM?hjDubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hjEhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjEhM?hjEubah}(h]h ]h"]h$]h&]uh1jhjDubeh}(h]h ]h"]h$]h&]uh1johjEhM?hjDubjp)}(hV``unsigned long flags`` Caller saved interrupt state, from read_seqlock_excl_irqsave()h](jv)}(h``unsigned long flags``h]j2)}(hj2Eh]hunsigned long flags}(hj4EhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj0Eubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMAhj,Eubj)}(hhh]h)}(h>Caller saved interrupt state, from read_seqlock_excl_irqsave()h]h>Caller saved interrupt state, from read_seqlock_excl_irqsave()}(hjKEhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM@hjHEubah}(h]h ]h"]h$]h&]uh1jhj,Eubeh}(h]h ]h"]h$]h&]uh1johjGEhMAhjDubeh}(h]h ]h"]h$]h&]uh1jjhjDubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j"read_seqbegin_or_lock (C function)c.read_seqbegin_or_lockhNtauh1jhjhhhNhNubj)}(hhh](j)}(h6void read_seqbegin_or_lock (seqlock_t *lock, int *seq)h]j)}(h5void read_seqbegin_or_lock(seqlock_t *lock, int *seq)h](j@)}(hvoidh]hvoid}(hjEhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjEhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMgubjR)}(h h]h }(hjEhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjEhhhjEhMgubj)}(hread_seqbegin_or_lockh]j)}(hread_seqbegin_or_lockh]hread_seqbegin_or_lock}(hjEhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjEubah}(h]h ](jjeh"]h$]h&]jjuh1jhjEhhhjEhMgubj{)}(h(seqlock_t *lock, int *seq)h](j)}(hseqlock_t *lockh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hjEhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjEubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetjEmodnameN classnameNjj)}j]j)}jjEsbc.read_seqbegin_or_lockasbuh1hhjEubjR)}(h h]h }(hjEhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjEubj)}(hjh]h*}(hjEhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjEubj)}(hlockh]hlock}(hjFhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjEubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjEubj)}(hint *seqh](j@)}(hinth]hint}(hj FhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjFubjR)}(h h]h }(hj.FhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjFubj)}(hjh]h*}(hj; this way, a lockless read can be optimistically tried first.}(hjGhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMKhjGubah}(h]h ]h"]h$]h&]uh1jhjFubeh}(h]h ]h"]h$]h&]uh1johjGhMPhjFubeh}(h]h ]h"]h$]h&]uh1jjhjFubh)}(h**Description**h]jU)}(hjqGh]h Description}(hjsGhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjoGubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMRhjFubh)}(hXread_seqbegin_or_lock is an API designed to optimistically try a normal lockless seqlock_t read section first. If an odd counter is found, the lockless read trial has failed, and the next read iteration transforms itself into a full seqlock_t locking reader.h]hXread_seqbegin_or_lock is an API designed to optimistically try a normal lockless seqlock_t read section first. If an odd counter is found, the lockless read trial has failed, and the next read iteration transforms itself into a full seqlock_t locking reader.}(hjGhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMRhjFubh)}(hThis is typically used to avoid seqlock_t lockless readers starvation (too much retry loops) in the case of a sharp spike in write side activity.h]hThis is typically used to avoid seqlock_t lockless readers starvation (too much retry loops) in the case of a sharp spike in write side activity.}(hjGhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMWhjFubh)}(hBCheck Documentation/locking/seqlock.rst for template example code.h]hBCheck Documentation/locking/seqlock.rst for template example code.}(hjGhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM[hjFubh)}(h **Context**h]jU)}(hjGh]hContext}(hjGhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjGubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM]hjFubh)}(hif the seqlock_t write section, *or other read sections*, can be invoked from hardirq or softirq contexts, use the _irqsave or _bh variant of this function instead.h](h if the seqlock_t write section, }(hjGhhhNhNubj;)}(h*or other read sections*h]hor other read sections}(hjGhhhNhNubah}(h]h ]h"]h$]h&]uh1j;hjGubhl, can be invoked from hardirq or softirq contexts, use the _irqsave or _bh variant of this function instead.}(hjGhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM[hjFubh)}(h **Return**h]jU)}(hjGh]hReturn}(hjGhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjGubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM_hjFubh)}(hXCthe encountered sequence counter value, through the **seq** parameter, which is overloaded as a return parameter. This returned value must be checked with need_seqretry(). If the read section need to be retried, this returned value must also be passed as the **seq** parameter of the next read_seqbegin_or_lock() iteration.h](h4the encountered sequence counter value, through the }(hjHhhhNhNubjU)}(h**seq**h]hseq}(hj HhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjHubh parameter, which is overloaded as a return parameter. This returned value must be checked with need_seqretry(). If the read section need to be retried, this returned value must also be passed as the }(hjHhhhNhNubjU)}(h**seq**h]hseq}(hjHhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjHubh9 parameter of the next read_seqbegin_or_lock() iteration.}(hjHhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMahjFubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jneed_seqretry (C function)c.need_seqretryhNtauh1jhjhhhNhNubj)}(hhh](j)}(h,int need_seqretry (seqlock_t *lock, int seq)h]j)}(h+int need_seqretry(seqlock_t *lock, int seq)h](j@)}(hinth]hint}(hjXHhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjTHhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMvubjR)}(h h]h }(hjgHhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjTHhhhjfHhMvubj)}(h need_seqretryh]j)}(h need_seqretryh]h need_seqretry}(hjyHhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjuHubah}(h]h ](jjeh"]h$]h&]jjuh1jhjTHhhhjfHhMvubj{)}(h(seqlock_t *lock, int seq)h](j)}(hseqlock_t *lockh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hjHhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjHubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetjHmodnameN classnameNjj)}j]j)}jj{Hsbc.need_seqretryasbuh1hhjHubjR)}(h h]h }(hjHhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjHubj)}(hjh]h*}(hjHhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjHubj)}(hlockh]hlock}(hjHhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjHubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjHubj)}(hint seqh](j@)}(hinth]hint}(hjHhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjHubjR)}(h h]h }(hjHhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjHubj)}(hseqh]hseq}(hjIhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjHubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjHubeh}(h]h ]h"]h$]h&]jjuh1jzhjTHhhhjfHhMvubeh}(h]h ]h"]h$]h&]jjjuh1jjjhjPHhhhjfHhMvubah}(h]jKHah ](jjeh"]h$]h&]jj)jhuh1jhjfHhMvhjMHhhubj)}(hhh]h)}(h5validate seqlock_t "locking or lockless" read sectionh]h9validate seqlock_t “locking or lockless” read section}(hj2IhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMphj/Ihhubah}(h]h ]h"]h$]h&]uh1jhjMHhhhjfHhMvubeh}(h]h ](jfunctioneh"]h$]h&]jjjjJIjjJIjjjuh1jhhhjhNhNubjK)}(h**Parameters** ``seqlock_t *lock`` Pointer to seqlock_t ``int seq`` sequence count, from read_seqbegin_or_lock() **Return** true if a read section retry is required, false otherwiseh](h)}(h**Parameters**h]jU)}(hjTIh]h Parameters}(hjVIhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjRIubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMthjNIubjk)}(hhh](jp)}(h)``seqlock_t *lock`` Pointer to seqlock_t h](jv)}(h``seqlock_t *lock``h]j2)}(hjsIh]hseqlock_t *lock}(hjuIhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjqIubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMqhjmIubj)}(hhh]h)}(hPointer to seqlock_th]!lhPointer to seqlock_t}(hjIhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjIhMqhjIubah}(h]h ]h"]h$]h&]uh1jhjmIubeh}(h]h ]h"]h$]h&]uh1johjIhMqhjjIubjp)}(h9``int seq`` sequence count, from read_seqbegin_or_lock() h](jv)}(h ``int seq``h]j2)}(hjIh]hint seq}(hjIhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjIubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMrhjIubj)}(hhh]h)}(h,sequence count, from read_seqbegin_or_lock()h]h,sequence count, from read_seqbegin_or_lock()}(hjIhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjIhMrhjIubah}(h]h ]h"]h$]h&]uh1jhjIubeh}(h]h ]h"]h$]h&]uh1johjIhMrhjjIubeh}(h]h ]h"]h$]h&]uh1jjhjNIubh)}(h **Return**h]jU)}(hjIh]hReturn}(hjIhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjIubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMthjNIubh)}(h9true if a read section retry is required, false otherwiseh]h9true if a read section retry is required, false otherwise}(hjIhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMthjNIubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](jdone_seqretry (C function)c.done_seqretryhNtauh1jhjhhhNhNubj)}(hhh](j)}(h-void done_seqretry (seqlock_t *lock, int seq)h]j)}(h,void done_seqretry(seqlock_t *lock, int seq)h](j@)}(hvoidh]hvoid}(hj,JhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj(JhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubjR)}(h h]h }(hj;JhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj(Jhhhj:JhMubj)}(h done_seqretryh]j)}(h done_seqretryh]h done_seqretry}(hjMJhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjIJubah}(h]h ](jjeh"]h$]h&]jjuh1jhj(Jhhhj:JhMubj{)}(h(seqlock_t *lock, int seq)h](j)}(hseqlock_t *lockh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hjlJhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjiJubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetjnJmodnameN classnameNjj)}j]j)}jjOJsbc.done_seqretryasbuh1hhjeJubjR)}(h h]h }(hjJhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjeJubj)}(hjh]h*}(hjJhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjeJubj)}(hlockh]hlock}(hjJhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjeJubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjaJubj)}(hint seqh](j@)}(hinth]hint}(hjJhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjJubjR)}(h h]h }(hjJhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjJubj)}(hseqh]hseq}(hjJhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjJubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjaJubeh}(h]h ]h"]h$]h&]jjuh1jzhj(Jhhhj:JhMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhj$Jhhhj:JhMubah}(h]jJah ](jjeh"]h$]h&]jj)jhuh1jhj:JhMhj!Jhhubj)}(hhh]h)}(h2end seqlock_t "locking or lockless" reader sectionh]h6end seqlock_t “locking or lockless” reader section}(hjKhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM|hjKhhubah}(h]h ]h"]h$]h&]uh1jhj!Jhhhj:JhMubeh}(h]h ](jfunctioneh"]h$]h&]jjjjKjjKjjjuh1jhhhjhNhNubjK)}(hX**Parameters** ``seqlock_t *lock`` Pointer to seqlock_t ``int seq`` count, from read_seqbegin_or_lock() **Description** done_seqretry finishes the seqlock_t read side critical section started with read_seqbegin_or_lock() and validated by need_seqretry().h](h)}(h**Parameters**h]jU)}(hj(Kh]h Parameters}(hj*KhhhNhNubah}(h]h ]h"]h$]h&]uh1jThj&Kubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj"Kubjk)}(hhh](jp)}(h)``seqlock_t *lock`` Pointer to seqlock_t h](jv)}(h``seqlock_t *lock``h]j2)}(hjGKh]hseqlock_t *lock}(hjIKhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjEKubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM}hjAKubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hj`KhhhNhNubah}(h]h ]h"]h$]h&]uh1hhj\KhM}hj]Kubah}(h]h ]h"]h$]h&]uh1jhjAKubeh}(h]h ]h"]h$]h&]uh1johj\KhM}hj>Kubjp)}(h0``int seq`` count, from read_seqbegin_or_lock() h](jv)}(h ``int seq``h]j2)}(hjKh]hint seq}(hjKhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj~Kubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhM~hjzKubj)}(hhh]h)}(h#count, from read_seqbegin_or_lock()h]h#count, from read_seqbegin_or_lock()}(hjKhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjKhM~hjKubah}(h]h ]h"]h$]h&]uh1jhjzKubeh}(h]h ]h"]h$]h&]uh1johjKhM~hj>Kubeh}(h]h ]h"]h$]h&]uh1jjhj"Kubh)}(h**Description**h]jU)}(hjKh]h Description}(hjKhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjKubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj"Kubh)}(hdone_seqretry finishes the seqlock_t read side critical section started with read_seqbegin_or_lock() and validated by need_seqretry().h]hdone_seqretry finishes the seqlock_t read side critical section started with read_seqbegin_or_lock() and validated by need_seqretry().}(hjKhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj"Kubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j*read_seqbegin_or_lock_irqsave (C function)c.read_seqbegin_or_lock_irqsavehNtauh1jhjhhhNhNubj)}(hhh](j)}(hGunsigned long read_seqbegin_or_lock_irqsave (seqlock_t *lock, int *seq)h]j)}(hFunsigned long read_seqbegin_or_lock_irqsave(seqlock_t *lock, int *seq)h](j@)}(hunsignedh]hunsigned}(hjLhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjKhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubjR)}(h h]h }(hjLhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjKhhhjLhMubj@)}(hlongh]hlong}(hjLhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjKhhhjLhMubjR)}(h h]h }(hj+LhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjKhhhjLhMubj)}(hread_seqbegin_or_lock_irqsaveh]j)}(hread_seqbegin_or_lock_irqsaveh]hread_seqbegin_or_lock_irqsave}(hj=LhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj9Lubah}(h]h ](jjeh"]h$]h&]jjuh1jhjKhhhjLhMubj{)}(h(seqlock_t *lock, int *seq)h](j)}(hseqlock_t *lockh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hj\LhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjYLubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetj^LmodnameN classnameNjj)}j]j)}jj?Lsbc.read_seqbegin_or_lock_irqsaveasbuh1hhjULubjR)}(h h]h }(hj|LhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjULubj)}(hjh]h*}(hjLhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjULubj)}(hlockh]hlock}(hjLhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjULubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjQLubj)}(hint *seqh](j@)}(hinth]hint}(hjLhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjLubjR)}(h h]h }(hjLhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjLubj)}(hjh]h*}(hjLhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjLubj)}(hseqh]hseq}(hjLhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjLubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjQLubeh}(h]h ]h"]h$]h&]jjuh1jzhjKhhhjLhMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhjKhhhjLhMubah}(h]jKah ](jjeh"]h$]h&]jj)jhuh1jhjLhMhjKhhubj)}(hhh]h)}(hHbegin a seqlock_t lockless reader, or a non-interruptible locking readerh]hHbegin a seqlock_t lockless reader, or a non-interruptible locking reader}(hjMhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjMhhubah}(h]h ]h"]h$]h&]uh1jhjKhhhjLhMubeh}(h]h ](jfunctioneh"]h$]h&]jjjjMjjMjjjuh1jhhhjhNhNubjK)}(hX**Parameters** ``seqlock_t *lock`` Pointer to seqlock_t ``int *seq`` Marker and return parameter. Check read_seqbegin_or_lock(). **Description** This is the _irqsave variant of read_seqbegin_or_lock(). Use it only if the seqlock_t write section, *or other read sections*, can be invoked from hardirq context. **Note** Interrupts will be disabled only for "locking reader" mode. **Return** 1. The saved local interrupts state in case of a locking reader, to be passed to done_seqretry_irqrestore(). 2. The encountered sequence counter value, returned through **seq** overloaded as a return parameter. Check read_seqbegin_or_lock().h](h)}(h**Parameters**h]jU)}(hj%Mh]h Parameters}(hj'MhhhNhNubah}(h]h ]h"]h$]h&]uh1jThj#Mubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjMubjk)}(hhh](jp)}(h)``seqlock_t *lock`` Pointer to seqlock_t h](jv)}(h``seqlock_t *lock``h]j2)}(hjDMh]hseqlock_t *lock}(hjFMhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjBMubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj>Mubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hj]MhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjYMhMhjZMubah}(h]h ]h"]h$]h&]uh1jhj>Mubeh}(h]h ]h"]h$]h&]uh1johjYMhMhj;Mubjp)}(hI``int *seq`` Marker and return parameter. Check read_seqbegin_or_lock(). h](jv)}(h ``int *seq``h]j2)}(hj}Mh]hint *seq}(hjMhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hj{Mubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjwMubj)}(hhh]h)}(h;Marker and return parameter. Check read_seqbegin_or_lock().h]h;Marker and return parameter. Check read_seqbegin_or_lock().}(hjMhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjMhMhjMubah}(h]h ]h"]h$]h&]uh1jhjwMubeh}(h]h ]h"]h$]h&]uh1johjMhMhj;Mubeh}(h]h ]h"]h$]h&]uh1jjhjMubh)}(h**Description**h]jU)}(hjMh]h Description}(hjMhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjMubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjMubh)}(hThis is the _irqsave variant of read_seqbegin_or_lock(). Use it only if the seqlock_t write section, *or other read sections*, can be invoked from hardirq context.h](heThis is the _irqsave variant of read_seqbegin_or_lock(). Use it only if the seqlock_t write section, }(hjMhhhNhNubj;)}(h*or other read sections*h]hor other read sections}(hjMhhhNhNubah}(h]h ]h"]h$]h&]uh1j;hjMubh&, can be invoked from hardirq context.}(hjMhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjMubh)}(h**Note**h]jU)}(hjMh]hNote}(hjMhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjMubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjMubh)}(h;Interrupts will be disabled only for "locking reader" mode.h]h?Interrupts will be disabled only for “locking reader” mode.}(hjNhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjMubh)}(h **Return**h]jU)}(hjNh]hReturn}(hjNhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjMubj)}(h1. The saved local interrupts state in case of a locking reader, to be passed to done_seqretry_irqrestore(). 2. The encountered sequence counter value, returned through **seq** overloaded as a return parameter. Check read_seqbegin_or_lock().h]j)}(hhh](j)}(hjThe saved local interrupts state in case of a locking reader, to be passed to done_seqretry_irqrestore(). h]h)}(hiThe saved local interrupts state in case of a locking reader, to be passed to done_seqretry_irqrestore().h]hiThe saved local interrupts state in case of a locking reader, to be passed to done_seqretry_irqrestore().}(hj9NhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj5Nubah}(h]h ]h"]h$]h&]uh1jhj2Nubj)}(hThe encountered sequence counter value, returned through **seq** overloaded as a return parameter. Check read_seqbegin_or_lock().h]h)}(hThe encountered sequence counter value, returned through **seq** overloaded as a return parameter. Check read_seqbegin_or_lock().h](h9The encountered sequence counter value, returned through }(hjRNhhhNhNubjU)}(h**seq**h]hseq}(hjZNhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjRNubhA overloaded as a return parameter. Check read_seqbegin_or_lock().}(hjRNhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjNNubah}(h]h ]h"]h$]h&]uh1jhj2Nubeh}(h]h ]h"]h$]h&]jjjhjjuh1j hj.Nubah}(h]h ]h"]h$]h&]uh1jhjGNhMhjMubeh}(h]h ] kernelindentah"]h$]h&]uh1jJhjhhhNhNubj)}(hhh]h}(h]h ]h"]h$]h&]entries](j%done_seqretry_irqrestore (C function)c.done_seqretry_irqrestorehNtauh1jhjhhhNhNubj)}(hhh](j)}(hMvoid done_seqretry_irqrestore (seqlock_t *lock, int seq, unsigned long flags)h]j)}(hLvoid done_seqretry_irqrestore(seqlock_t *lock, int seq, unsigned long flags)h](j@)}(hvoidh]hvoid}(hjNhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjNhhhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMubjR)}(h h]h }(hjNhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjNhhhjNhMubj)}(hdone_seqretry_irqrestoreh]j)}(hdone_seqretry_irqrestoreh]hdone_seqretry_irqrestore}(hjNhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjNubah}(h]h ](jjeh"]h$]h&]jjuh1jhjNhhhjNhMubj{)}(h/(seqlock_t *lock, int seq, unsigned long flags)h](j)}(hseqlock_t *lockh](h)}(hhh]j)}(h seqlock_th]h seqlock_t}(hjNhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjNubah}(h]h ]h"]h$]h&] refdomainjreftypej reftargetjNmodnameN classnameNjj)}j]j)}jjNsbc.done_seqretry_irqrestoreasbuh1hhjNubjR)}(h h]h }(hjOhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjNubj)}(hjh]h*}(hjOhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjNubj)}(hlockh]hlock}(hj OhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjNubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjNubj)}(hint seqh](j@)}(hinth]hint}(hj9OhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hj5OubjR)}(h h]h }(hjGOhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhj5Oubj)}(hseqh]hseq}(hjUOhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhj5Oubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjNubj)}(hunsigned long flagsh](j@)}(hunsignedh]hunsigned}(hjnOhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjjOubjR)}(h h]h }(hj|OhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjjOubj@)}(hlongh]hlong}(hjOhhhNhNubah}(h]h ]jLah"]h$]h&]uh1j?hjjOubjR)}(h h]h }(hjOhhhNhNubah}(h]h ]j^ah"]h$]h&]uh1jQhjjOubj)}(hflagsh]hflags}(hjOhhhNhNubah}(h]h ]jah"]h$]h&]uh1jhjjOubeh}(h]h ]h"]h$]h&]noemphjjuh1jhjNubeh}(h]h ]h"]h$]h&]jjuh1jzhjNhhhjNhMubeh}(h]h ]h"]h$]h&]jjjuh1jjjhjNhhhjNhMubah}(h]jNah ](jjeh"]h$]h&]jj)jhuh1jhjNhMhjNhhubj)}(hhh]h)}(hNend a seqlock_t lockless reader, or a non-interruptible locking reader sectionh]hNend a seqlock_t lockless reader, or a non-interruptible locking reader section}(hjOhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjOhhubah}(h]h ]h"]h$]h&]uh1jhjNhhhjNhMubeh}(h]h ](jfunctioneh"]h$]h&]jjjjOjjOjjjuh1jhhhjhNhNubjK)}(hX**Parameters** ``seqlock_t *lock`` Pointer to seqlock_t ``int seq`` Count, from read_seqbegin_or_lock_irqsave() ``unsigned long flags`` Caller's saved local interrupt state in case of a locking reader, also from read_seqbegin_or_lock_irqsave() **Description** This is the _irqrestore variant of done_seqretry(). The read section must've been opened with read_seqbegin_or_lock_irqsave(), and validated by need_seqretry().h](h)}(h**Parameters**h]jU)}(hjOh]h Parameters}(hjOhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjOubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjOubjk)}(hhh](jp)}(h)``seqlock_t *lock`` Pointer to seqlock_t h](jv)}(h``seqlock_t *lock``h]j2)}(hjPh]hseqlock_t *lock}(hjPhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjPubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj Pubj)}(hhh]h)}(hPointer to seqlock_th]hPointer to seqlock_t}(hj*PhhhNhNubah}(h]h ]h"]h$]h&]uh1hhj&PhMhj'Pubah}(h]h ]h"]h$]h&]uh1jhj Pubeh}(h]h ]h"]h$]h&]uh1johj&PhMhjPubjp)}(h8``int seq`` Count, from read_seqbegin_or_lock_irqsave() h](jv)}(h ``int seq``h]j2)}(hjJPh]hint seq}(hjLPhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjHPubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjDPubj)}(hhh]h)}(h+Count, from read_seqbegin_or_lock_irqsave()h]h+Count, from read_seqbegin_or_lock_irqsave()}(hjcPhhhNhNubah}(h]h ]h"]h$]h&]uh1hhj_PhMhj`Pubah}(h]h ]h"]h$]h&]uh1jhjDPubeh}(h]h ]h"]h$]h&]uh1johj_PhMhjPubjp)}(h``unsigned long flags`` Caller's saved local interrupt state in case of a locking reader, also from read_seqbegin_or_lock_irqsave() h](jv)}(h``unsigned long flags``h]j2)}(hjPh]hunsigned long flags}(hjPhhhNhNubah}(h]h ]h"]h$]h&]uh1j1hjPubah}(h]h ]h"]h$]h&]uh1juhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhj}Pubj)}(hhh]h)}(hkCaller's saved local interrupt state in case of a locking reader, also from read_seqbegin_or_lock_irqsave()h]hmCaller’s saved local interrupt state in case of a locking reader, also from read_seqbegin_or_lock_irqsave()}(hjPhhhNhNubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjPubah}(h]h ]h"]h$]h&]uh1jhj}Pubeh}(h]h ]h"]h$]h&]uh1johjPhMhjPubeh}(h]h ]h"]h$]h&]uh1jjhjOubh)}(h**Description**h]jU)}(hjPh]h Description}(hjPhhhNhNubah}(h]h ]h"]h$]h&]uh1jThjPubah}(h]h ]h"]h$]h&]uh1hhX/var/lib/git/docbuild/linux/Documentation/locking/seqlock:239: ./include/linux/seqlock.hhMhjOubh)}(hThis is the _irqrestore variant of done_seqretry(). The read section must've been opened with read_seqbegin_or_lock_irqsave(), and validated by need_seqretry().h]hThis is the _irqrestore variant of done_seqretry(). 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