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Commit 6b44f519 authored by Scot Doyle's avatar Scot Doyle Committed by Ingo Molnar
Browse files

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: default avatarScot Doyle <lkml14@scotdoyle.com>
Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
parent 35b123e2

include/linux/wait.h

+10 −6
Original line number Diff line number Diff line
@@ -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)	\

({									\