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| author | Dipankar Sarma <dipankar@in.ibm.com> | 2004-08-22 22:58:51 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-08-22 22:58:51 -0700 |
| commit | 5dae7a69a46f3a9f6562a4702f8beaa7f77e94f6 (patch) | |
| tree | 40daf62eb530c10372f9cb90f600a0b040c5e725 /arch | |
| parent | 9711268caede0cbd322244d70145a6e914fac52e (diff) | |
| download | history-5dae7a69a46f3a9f6562a4702f8beaa7f77e94f6.tar.gz | |
[PATCH] rcu: abstracted RCU dereferencing
Use abstracted RCU API to dereference RCU protected data. Hides barrier
details. Patch from Paul McKenney.
This patch introduced an rcu_dereference() macro that replaces most uses of
smp_read_barrier_depends(). The new macro has the advantage of explicitly
documenting which pointers are protected by RCU -- in contrast, it is
sometimes difficult to figure out which pointer is being protected by a given
smp_read_barrier_depends() call.
Signed-off-by: Paul McKenney <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86_64/kernel/mce.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/arch/x86_64/kernel/mce.c b/arch/x86_64/kernel/mce.c index 3bb678f1eb60aa..0399360a18eb2c 100644 --- a/arch/x86_64/kernel/mce.c +++ b/arch/x86_64/kernel/mce.c @@ -48,8 +48,7 @@ static void mce_log(struct mce *mce) mce->finished = 0; smp_wmb(); for (;;) { - entry = mcelog.next; - read_barrier_depends(); + entry = rcu_dereference(mcelog.next); /* When the buffer fills up discard new entries. Assume that the earlier errors are the more interesting. */ if (entry >= MCE_LOG_LEN) { @@ -333,9 +332,8 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize, loff int i, err; down(&mce_read_sem); - next = mcelog.next; - read_barrier_depends(); - + next = rcu_dereference(mcelog.next); + /* Only supports full reads right now */ if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) { up(&mce_read_sem); |