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| author | Peter Zijlstra <peterz@infradead.org> | 2013-10-02 11:22:19 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-10-04 10:14:44 +0200 |
| commit | 2953ef246b058989657e1e77b36b67566ac06f7b (patch) | |
| tree | a63c8aff38d86f4a7db7eb4e5111dc46076cc268 /include/linux/wait.h | |
| parent | 2f2a2b60adf368bacd6acd2116c01e32caf936c4 (diff) | |
| download | linux-2953ef246b058989657e1e77b36b67566ac06f7b.tar.gz linux-2953ef246b058989657e1e77b36b67566ac06f7b.tar.bz2 linux-2953ef246b058989657e1e77b36b67566ac06f7b.zip | |
sched/wait: Change timeout logic
Commit 4c663cf ("wait: fix false timeouts when using
wait_event_timeout()") introduced an additional condition check after
a timeout but there's a few issues;
- it forgot one site
- it put the check after the main loop; not at the actual timeout
check.
Cure both; by wrapping the condition (as suggested by Oleg), this
avoids double evaluation of 'condition' which could be quite big.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131002092528.028892896@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/wait.h')
| -rw-r--r-- | include/linux/wait.h | 24 |
1 files changed, 11 insertions, 13 deletions
diff --git a/include/linux/wait.h b/include/linux/wait.h index ccf0c529fd37..b2afd665e4ea 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -179,6 +179,14 @@ wait_queue_head_t *bit_waitqueue(void *, int); #define wake_up_interruptible_sync_poll(x, m) \ __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m)) +#define ___wait_cond_timeout(condition, ret) \ +({ \ + bool __cond = (condition); \ + if (__cond && !ret) \ + ret = 1; \ + __cond || !ret; \ +}) + #define __wait_event(wq, condition) \ do { \ DEFINE_WAIT(__wait); \ @@ -217,14 +225,10 @@ do { \ \ for (;;) { \ prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \ - if (condition) \ + if (___wait_cond_timeout(condition, ret)) \ break; \ ret = schedule_timeout(ret); \ - if (!ret) \ - break; \ } \ - if (!ret && (condition)) \ - ret = 1; \ finish_wait(&wq, &__wait); \ } while (0) @@ -299,18 +303,14 @@ do { \ \ for (;;) { \ prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \ - if (condition) \ + if (___wait_cond_timeout(condition, ret)) \ break; \ if (signal_pending(current)) { \ ret = -ERESTARTSYS; \ break; \ } \ ret = schedule_timeout(ret); \ - if (!ret) \ - break; \ } \ - if (!ret && (condition)) \ - ret = 1; \ finish_wait(&wq, &__wait); \ } while (0) @@ -815,7 +815,7 @@ do { \ \ for (;;) { \ prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \ - if (condition) \ + if (___wait_cond_timeout(condition, ret)) \ break; \ if (signal_pending(current)) { \ ret = -ERESTARTSYS; \ @@ -824,8 +824,6 @@ do { \ spin_unlock_irq(&lock); \ ret = schedule_timeout(ret); \ spin_lock_irq(&lock); \ - if (!ret) \ - break; \ } \ finish_wait(&wq, &__wait); \ } while (0) |