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| author | Scot Doyle <lkml14@scotdoyle.com> | 2014-08-24 17:12:27 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-09-05 12:37:10 +0200 |
| commit | 6b44f519017b219a12b37173c7eef8dfce2c0100 (patch) | |
| tree | 011afccc53ba6ac2e63ab8ab779c5e2ef79925b2 /include/linux/wait.h | |
| parent | 35b123e2f701b28977db2cde7dbbdb3fad28cad1 (diff) | |
| download | lwn-6b44f519017b219a12b37173c7eef8dfce2c0100.tar.gz lwn-6b44f519017b219a12b37173c7eef8dfce2c0100.zip | |
sched/wait: Document timeout corner case
The timeout may elapse without 0 being returned, such as when waiting
on an unused queue. Document this possibility.
Signed-off-by: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.LNX.2.11.1408241710070.6462@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/wait.h')
| -rw-r--r-- | include/linux/wait.h | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/include/linux/wait.h b/include/linux/wait.h index 6fb1ba5f9b2f..034f6fc7c65f 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -280,9 +280,11 @@ do { \ * wake_up() has to be called after changing any variable that could * change the result of the wait condition. * - * The function returns 0 if the @timeout elapsed, or the remaining - * jiffies (at least 1) if the @condition evaluated to %true before - * the @timeout elapsed. + * Returns: + * 0 if the @condition evaluated to %false after the @timeout elapsed, + * 1 if the @condition evaluated to %true after the @timeout elapsed, + * or the remaining jiffies (at least 1) if the @condition evaluated + * to %true before the @timeout elapsed. */ #define wait_event_timeout(wq, condition, timeout) \ ({ \ @@ -363,9 +365,11 @@ do { \ * change the result of the wait condition. * * Returns: - * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by - * a signal, or the remaining jiffies (at least 1) if the @condition - * evaluated to %true before the @timeout elapsed. + * 0 if the @condition evaluated to %false after the @timeout elapsed, + * 1 if the @condition evaluated to %true after the @timeout elapsed, + * the remaining jiffies (at least 1) if the @condition evaluated + * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was + * interrupted by a signal. */ #define wait_event_interruptible_timeout(wq, condition, timeout) \ ({ \ |