€•I^      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ/translations/zh_CN/RCU/lockdep”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ/translations/zh_TW/RCU/lockdep”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ/translations/it_IT/RCU/lockdep”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ/translations/ja_JP/RCU/lockdep”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ/translations/ko_KR/RCU/lockdep”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒPortuguese (Brazilian)”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ/translations/pt_BR/RCU/lockdep”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh–sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ/translations/sp_SP/RCU/lockdep”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒ SPDX-License-Identifier: GPL-2.0”h]”hŒ SPDX-License-Identifier: GPL-2.0”…””}”hh·sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1hµhhh²hh³Œ9/var/lib/git/docbuild/linux/Documentation/RCU/lockdep.rst”h´KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒRCU and lockdep checking”h]”hŒRCU and lockdep checking”…””}”(hhÏh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhhÊh²hh³hÇh´KubhŒ	paragraph”“”)”}”(hXz  All flavors of RCU have lockdep checking available, so that lockdep is
aware of when each task enters and leaves any flavor of RCU read-side
critical section.  Each flavor of RCU is tracked separately (but note
that this is not the case in 2.6.32 and earlier).  This allows lockdep's
tracking to include RCU state, which can sometimes help when debugging
deadlocks and the like.”h]”hX|  All flavors of RCU have lockdep checking available, so that lockdep is
aware of when each task enters and leaves any flavor of RCU read-side
critical section.  Each flavor of RCU is tracked separately (but note
that this is not the case in 2.6.32 and earlier).  This allows lockdepâ€™s
tracking to include RCU state, which can sometimes help when debugging
deadlocks and the like.”…””}”(hhßh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KhhÊh²hubhÞ)”}”(hŒOIn addition, RCU provides the following primitives that check lockdep's
state::”h]”hŒPIn addition, RCU provides the following primitives that check lockdepâ€™s
state:”…””}”(hhíh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KhhÊh²hubhŒliteral_block”“”)”}”(hX	  rcu_read_lock_held() for normal RCU.
rcu_read_lock_bh_held() for RCU-bh.
rcu_read_lock_sched_held() for RCU-sched.
rcu_read_lock_any_held() for any of normal RCU, RCU-bh, and RCU-sched.
srcu_read_lock_held() for SRCU.
rcu_read_lock_trace_held() for RCU Tasks Trace.”h]”hX	  rcu_read_lock_held() for normal RCU.
rcu_read_lock_bh_held() for RCU-bh.
rcu_read_lock_sched_held() for RCU-sched.
rcu_read_lock_any_held() for any of normal RCU, RCU-bh, and RCU-sched.
srcu_read_lock_held() for SRCU.
rcu_read_lock_trace_held() for RCU Tasks Trace.”…””}”hhýsbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1hûh³hÇh´KhhÊh²hubhÞ)”}”(hŒùThese functions are conservative, and will therefore return 1 if they
aren't certain (for example, if CONFIG_DEBUG_LOCK_ALLOC is not set).
This prevents things like WARN_ON(!rcu_read_lock_held()) from giving false
positives when lockdep is disabled.”h]”hŒûThese functions are conservative, and will therefore return 1 if they
arenâ€™t certain (for example, if CONFIG_DEBUG_LOCK_ALLOC is not set).
This prevents things like WARN_ON(!rcu_read_lock_held()) from giving false
positives when lockdep is disabled.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KhhÊh²hubhÞ)”}”(hŒrIn addition, a separate kernel config parameter CONFIG_PROVE_RCU enables
checking of rcu_dereference() primitives:”h]”hŒrIn addition, a separate kernel config parameter CONFIG_PROVE_RCU enables
checking of rcu_dereference() primitives:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KhhÊh²hubhŒblock_quote”“”)”}”(hX  rcu_dereference(p):
        Check for RCU read-side critical section.
rcu_dereference_bh(p):
        Check for RCU-bh read-side critical section.
rcu_dereference_sched(p):
        Check for RCU-sched read-side critical section.
srcu_dereference(p, sp):
        Check for SRCU read-side critical section.
rcu_dereference_check(p, c):
        Use explicit check expression "c" along with
        rcu_read_lock_held().  This is useful in code that is
        invoked by both RCU readers and updaters.
rcu_dereference_bh_check(p, c):
        Use explicit check expression "c" along with
        rcu_read_lock_bh_held().  This is useful in code that
        is invoked by both RCU-bh readers and updaters.
rcu_dereference_sched_check(p, c):
        Use explicit check expression "c" along with
        rcu_read_lock_sched_held().  This is useful in code that
        is invoked by both RCU-sched readers and updaters.
srcu_dereference_check(p, c):
        Use explicit check expression "c" along with
        srcu_read_lock_held().  This is useful in code that
        is invoked by both SRCU readers and updaters.
rcu_dereference_raw(p):
        Don't check.  (Use sparingly, if at all.)
rcu_dereference_raw_check(p):
        Don't do lockdep at all.  (Use sparingly, if at all.)
rcu_dereference_protected(p, c):
        Use explicit check expression "c", and omit all barriers
        and compiler constraints.  This is useful when the data
        structure cannot change, for example, in code that is
        invoked only by updaters.
rcu_access_pointer(p):
        Return the value of the pointer and omit all barriers,
        but retain the compiler constraints that prevent duplicating
        or coalescing.  This is useful when testing the
        value of the pointer itself, for example, against NULL.
”h]”hŒdefinition_list”“”)”}”(hhh]”(hŒdefinition_list_item”“”)”}”(hŒ=rcu_dereference(p):
Check for RCU read-side critical section.”h]”(hŒterm”“”)”}”(hŒrcu_dereference(p):”h]”hŒrcu_dereference(p):”…””}”(hj:  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K hj4  ubhŒ
definition”“”)”}”(hhh]”hÞ)”}”(hŒ)Check for RCU read-side critical section.”h]”hŒ)Check for RCU read-side critical section.”…””}”(hjM  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K!hjJ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hj4  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K hj/  ubj3  )”}”(hŒCrcu_dereference_bh(p):
Check for RCU-bh read-side critical section.”h]”(j9  )”}”(hŒrcu_dereference_bh(p):”h]”hŒrcu_dereference_bh(p):”…””}”(hjk  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K"hjg  ubjI  )”}”(hhh]”hÞ)”}”(hŒ,Check for RCU-bh read-side critical section.”h]”hŒ,Check for RCU-bh read-side critical section.”…””}”(hj|  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K#hjy  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hjg  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K"hj/  ubj3  )”}”(hŒIrcu_dereference_sched(p):
Check for RCU-sched read-side critical section.”h]”(j9  )”}”(hŒrcu_dereference_sched(p):”h]”hŒrcu_dereference_sched(p):”…””}”(hjš  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K$hj–  ubjI  )”}”(hhh]”hÞ)”}”(hŒ/Check for RCU-sched read-side critical section.”h]”hŒ/Check for RCU-sched read-side critical section.”…””}”(hj«  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K%hj¨  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hj–  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K$hj/  ubj3  )”}”(hŒCsrcu_dereference(p, sp):
Check for SRCU read-side critical section.”h]”(j9  )”}”(hŒsrcu_dereference(p, sp):”h]”hŒsrcu_dereference(p, sp):”…””}”(hjÉ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K&hjÅ  ubjI  )”}”(hhh]”hÞ)”}”(hŒ*Check for SRCU read-side critical section.”h]”hŒ*Check for SRCU read-side critical section.”…””}”(hjÚ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K'hj×  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hjÅ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K&hj/  ubj3  )”}”(hŒ©rcu_dereference_check(p, c):
Use explicit check expression "c" along with
rcu_read_lock_held().  This is useful in code that is
invoked by both RCU readers and updaters.”h]”(j9  )”}”(hŒrcu_dereference_check(p, c):”h]”hŒrcu_dereference_check(p, c):”…””}”(hjø  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K*hjô  ubjI  )”}”(hhh]”hÞ)”}”(hŒŒUse explicit check expression "c" along with
rcu_read_lock_held().  This is useful in code that is
invoked by both RCU readers and updaters.”h]”hŒUse explicit check expression â€œcâ€ along with
rcu_read_lock_held().  This is useful in code that is
invoked by both RCU readers and updaters.”…””}”(hj	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K)hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hjô  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K*hj/  ubj3  )”}”(hŒ²rcu_dereference_bh_check(p, c):
Use explicit check expression "c" along with
rcu_read_lock_bh_held().  This is useful in code that
is invoked by both RCU-bh readers and updaters.”h]”(j9  )”}”(hŒrcu_dereference_bh_check(p, c):”h]”hŒrcu_dereference_bh_check(p, c):”…””}”(hj'  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K.hj#  ubjI  )”}”(hhh]”hÞ)”}”(hŒ’Use explicit check expression "c" along with
rcu_read_lock_bh_held().  This is useful in code that
is invoked by both RCU-bh readers and updaters.”h]”hŒ–Use explicit check expression â€œcâ€ along with
rcu_read_lock_bh_held().  This is useful in code that
is invoked by both RCU-bh readers and updaters.”…””}”(hj8  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K-hj5  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hj#  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K.hj/  ubj3  )”}”(hŒ»rcu_dereference_sched_check(p, c):
Use explicit check expression "c" along with
rcu_read_lock_sched_held().  This is useful in code that
is invoked by both RCU-sched readers and updaters.”h]”(j9  )”}”(hŒ"rcu_dereference_sched_check(p, c):”h]”hŒ"rcu_dereference_sched_check(p, c):”…””}”(hjV  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K2hjR  ubjI  )”}”(hhh]”hÞ)”}”(hŒ˜Use explicit check expression "c" along with
rcu_read_lock_sched_held().  This is useful in code that
is invoked by both RCU-sched readers and updaters.”h]”hŒœUse explicit check expression â€œcâ€ along with
rcu_read_lock_sched_held().  This is useful in code that
is invoked by both RCU-sched readers and updaters.”…””}”(hjg  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K1hjd  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hjR  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K2hj/  ubj3  )”}”(hŒ¬srcu_dereference_check(p, c):
Use explicit check expression "c" along with
srcu_read_lock_held().  This is useful in code that
is invoked by both SRCU readers and updaters.”h]”(j9  )”}”(hŒsrcu_dereference_check(p, c):”h]”hŒsrcu_dereference_check(p, c):”…””}”(hj…  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K6hj  ubjI  )”}”(hhh]”hÞ)”}”(hŒŽUse explicit check expression "c" along with
srcu_read_lock_held().  This is useful in code that
is invoked by both SRCU readers and updaters.”h]”hŒ’Use explicit check expression â€œcâ€ along with
srcu_read_lock_held().  This is useful in code that
is invoked by both SRCU readers and updaters.”…””}”(hj–  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K5hj“  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K6hj/  ubj3  )”}”(hŒArcu_dereference_raw(p):
Don't check.  (Use sparingly, if at all.)”h]”(j9  )”}”(hŒrcu_dereference_raw(p):”h]”hŒrcu_dereference_raw(p):”…””}”(hj´  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K8hj°  ubjI  )”}”(hhh]”hÞ)”}”(hŒ)Don't check.  (Use sparingly, if at all.)”h]”hŒ+Donâ€™t check.  (Use sparingly, if at all.)”…””}”(hjÅ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K9hjÂ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hj°  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K8hj/  ubj3  )”}”(hŒSrcu_dereference_raw_check(p):
Don't do lockdep at all.  (Use sparingly, if at all.)”h]”(j9  )”}”(hŒrcu_dereference_raw_check(p):”h]”hŒrcu_dereference_raw_check(p):”…””}”(hjã  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K:hjß  ubjI  )”}”(hhh]”hÞ)”}”(hŒ5Don't do lockdep at all.  (Use sparingly, if at all.)”h]”hŒ7Donâ€™t do lockdep at all.  (Use sparingly, if at all.)”…””}”(hjô  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K;hjñ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hjß  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K:hj/  ubj3  )”}”(hŒárcu_dereference_protected(p, c):
Use explicit check expression "c", and omit all barriers
and compiler constraints.  This is useful when the data
structure cannot change, for example, in code that is
invoked only by updaters.”h]”(j9  )”}”(hŒ rcu_dereference_protected(p, c):”h]”hŒ rcu_dereference_protected(p, c):”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´K?hj  ubjI  )”}”(hhh]”hÞ)”}”(hŒÀUse explicit check expression "c", and omit all barriers
and compiler constraints.  This is useful when the data
structure cannot change, for example, in code that is
invoked only by updaters.”h]”hŒÄUse explicit check expression â€œcâ€, and omit all barriers
and compiler constraints.  This is useful when the data
structure cannot change, for example, in code that is
invoked only by updaters.”…””}”(hj#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K=hj   ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´K?hj/  ubj3  )”}”(hŒórcu_access_pointer(p):
Return the value of the pointer and omit all barriers,
but retain the compiler constraints that prevent duplicating
or coalescing.  This is useful when testing the
value of the pointer itself, for example, against NULL.
”h]”(j9  )”}”(hŒrcu_access_pointer(p):”h]”hŒrcu_access_pointer(p):”…””}”(hjA  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j8  h³hÇh´KEhj=  ubjI  )”}”(hhh]”hÞ)”}”(hŒÛReturn the value of the pointer and omit all barriers,
but retain the compiler constraints that prevent duplicating
or coalescing.  This is useful when testing the
value of the pointer itself, for example, against NULL.”h]”hŒÛReturn the value of the pointer and omit all barriers,
but retain the compiler constraints that prevent duplicating
or coalescing.  This is useful when testing the
value of the pointer itself, for example, against NULL.”…””}”(hjR  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KBhjO  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jH  hj=  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j2  h³hÇh´KEhj/  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j-  hj)  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j'  h³hÇh´K hhÊh²hubhÞ)”}”(hŒ·The rcu_dereference_check() check expression can be any boolean
expression, but would normally include a lockdep expression.  For a
moderately ornate example, consider the following::”h]”hŒ¶The rcu_dereference_check() check expression can be any boolean
expression, but would normally include a lockdep expression.  For a
moderately ornate example, consider the following:”…””}”(hjx  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KGhhÊh²hubhü)”}”(hŒ«file = rcu_dereference_check(fdt->fd[fd],
                             lockdep_is_held(&files->file_lock) ||
                             atomic_read(&files->count) == 1);”h]”hŒ«file = rcu_dereference_check(fdt->fd[fd],
                             lockdep_is_held(&files->file_lock) ||
                             atomic_read(&files->count) == 1);”…””}”hj†  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1hûh³hÇh´KKhhÊh²hubhÞ)”}”(hŒ›This expression picks up the pointer "fdt->fd[fd]" in an RCU-safe manner,
and, if CONFIG_PROVE_RCU is configured, verifies that this expression
is used in:”h]”hŒŸThis expression picks up the pointer â€œfdt->fd[fd]â€ in an RCU-safe manner,
and, if CONFIG_PROVE_RCU is configured, verifies that this expression
is used in:”…””}”(hj”  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KOhhÊh²hubhŒenumerated_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒ0An RCU read-side critical section (implicit), or”h]”hÞ)”}”(hj«  h]”hŒ0An RCU read-side critical section (implicit), or”…””}”(hj­  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KShj©  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j§  hj¤  h²hh³hÇh´Nubj¨  )”}”(hŒwith files->file_lock held, or”h]”hÞ)”}”(hjÂ  h]”hŒwith files->file_lock held, or”…””}”(hjÄ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KThjÀ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j§  hj¤  h²hh³hÇh´Nubj¨  )”}”(hŒon an unshared files_struct.
”h]”hÞ)”}”(hŒon an unshared files_struct.”h]”hŒon an unshared files_struct.”…””}”(hjÛ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KUhj×  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j§  hj¤  h²hh³hÇh´Nubeh}”(h]”h ]”h"]”h$]”h&]”Œenumtype”Œarabic”Œprefix”hŒsuffix”Œ.”uh1j¢  hhÊh²hh³hÇh´KSubhÞ)”}”(hX•  In case (1), the pointer is picked up in an RCU-safe manner for vanilla
RCU read-side critical sections, in case (2) the ->file_lock prevents
any change from taking place, and finally, in case (3) the current task
is the only task accessing the file_struct, again preventing any change
from taking place.  If the above statement was invoked only from updater
code, it could instead be written as follows::”h]”hX”  In case (1), the pointer is picked up in an RCU-safe manner for vanilla
RCU read-side critical sections, in case (2) the ->file_lock prevents
any change from taking place, and finally, in case (3) the current task
is the only task accessing the file_struct, again preventing any change
from taking place.  If the above statement was invoked only from updater
code, it could instead be written as follows:”…””}”(hjú  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KWhhÊh²hubhü)”}”(hŒ·file = rcu_dereference_protected(fdt->fd[fd],
                                 lockdep_is_held(&files->file_lock) ||
                                 atomic_read(&files->count) == 1);”h]”hŒ·file = rcu_dereference_protected(fdt->fd[fd],
                                 lockdep_is_held(&files->file_lock) ||
                                 atomic_read(&files->count) == 1);”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1hûh³hÇh´K^hhÊh²hubhÞ)”}”(hX÷  This would verify cases #2 and #3 above, and furthermore lockdep would
complain even if this was used in an RCU read-side critical section unless
one of these two cases held.  Because rcu_dereference_protected() omits
all barriers and compiler constraints, it generates better code than do
the other flavors of rcu_dereference().  On the other hand, it is illegal
to use rcu_dereference_protected() if either the RCU-protected pointer
or the RCU-protected data that it points to can change concurrently.”h]”hX÷  This would verify cases #2 and #3 above, and furthermore lockdep would
complain even if this was used in an RCU read-side critical section unless
one of these two cases held.  Because rcu_dereference_protected() omits
all barriers and compiler constraints, it generates better code than do
the other flavors of rcu_dereference().  On the other hand, it is illegal
to use rcu_dereference_protected() if either the RCU-protected pointer
or the RCU-protected data that it points to can change concurrently.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KbhhÊh²hubhÞ)”}”(hX¬  Like rcu_dereference(), when lockdep is enabled, RCU list and hlist
traversal primitives check for being called from within an RCU read-side
critical section.  However, a lockdep expression can be passed to them
as an additional optional argument.  With this lockdep expression, these
traversal primitives will complain only if the lockdep expression is
false and they are called from outside any RCU read-side critical section.”h]”hX¬  Like rcu_dereference(), when lockdep is enabled, RCU list and hlist
traversal primitives check for being called from within an RCU read-side
critical section.  However, a lockdep expression can be passed to them
as an additional optional argument.  With this lockdep expression, these
traversal primitives will complain only if the lockdep expression is
false and they are called from outside any RCU read-side critical section.”…””}”(hj$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KjhhÊh²hubhÞ)”}”(hŒ²For example, the workqueue for_each_pwq() macro is intended to be used
either within an RCU read-side critical section or with wq->mutex held.
It is thus implemented as follows::”h]”hŒ±For example, the workqueue for_each_pwq() macro is intended to be used
either within an RCU read-side critical section or with wq->mutex held.
It is thus implemented as follows:”…””}”(hj2  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KqhhÊh²hubhü)”}”(hŒ #define for_each_pwq(pwq, wq)
        list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node,
                                lock_is_held(&(wq->mutex).dep_map))”h]”hŒ #define for_each_pwq(pwq, wq)
        list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node,
                                lock_is_held(&(wq->mutex).dep_map))”…””}”hj@  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1hûh³hÇh´KuhhÊh²hubeh}”(h]”Œrcu-and-lockdep-checking”ah ]”h"]”Œrcu and lockdep checking”ah$]”h&]”uh1hÈhhh²hh³hÇh´Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”hÇuh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(hÍNŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ	traceback”ˆŒinput_encoding”Œ	utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”jy  Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œlanguage_code”Œen”Œrecord_dependencies”NŒconfig”NŒ	id_prefix”hŒauto_id_prefix”Œid”Œdump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”hÇŒ_destination”NŒ_config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ	tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œdocinfo_xform”KŒsectsubtitle_xform”‰Œimage_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”jS  jP  sŒ	nametypes”}”jS  ‰sh}”jP  hÊsŒfootnote_refs”}”Œcitation_refs”}”Œautofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ	footnotes”]”Œ	citations”]”Œautofootnote_start”KŒsymbol_footnote_start”K Œ
id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
decoration”Nh²hub.