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Commit c6dc7f05 authored by J. Bruce Fields's avatar J. Bruce Fields Committed by Ingo Molnar
Browse files

sched: Document wait_for_completion_*() return values 



The return-value convention for these functions varies depending on
whether they're interruptible or can timeout.  It can be a little
confusing--document it.

Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111006192246.GB28026@fieldses.org


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 461819ac

kernel/sched.c

+13 −0
Original line number Diff line number Diff line
@@ -4810,6 +4810,9 @@ EXPORT_SYMBOL(wait_for_completion); 
 * This waits for either a completion of a specific task to be signaled or for a

 * specified timeout to expire. The timeout is in jiffies. It is not

 * interruptible.

 *

 * The return value is 0 if timed out, and positive (at least 1, or number of

 * jiffies left till timeout) if completed.

 */

unsigned long __sched

wait_for_completion_timeout(struct completion *x, unsigned long timeout)
@@ -4824,6 +4827,8 @@ EXPORT_SYMBOL(wait_for_completion_timeout); 
 *

 * This waits for completion of a specific task to be signaled. It is

 * interruptible.

 *

 * The return value is -ERESTARTSYS if interrupted, 0 if completed.

 */

int __sched wait_for_completion_interruptible(struct completion *x)

{
@@ -4841,6 +4846,9 @@ EXPORT_SYMBOL(wait_for_completion_interruptible); 
 *

 * This waits for either a completion of a specific task to be signaled or for a

 * specified timeout to expire. It is interruptible. The timeout is in jiffies.

 *

 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,

 * positive (at least 1, or number of jiffies left till timeout) if completed.

 */

long __sched

wait_for_completion_interruptible_timeout(struct completion *x,
@@ -4856,6 +4864,8 @@ EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); 
 *

 * This waits to be signaled for completion of a specific task. It can be

 * interrupted by a kill signal.

 *

 * The return value is -ERESTARTSYS if interrupted, 0 if completed.

 */

int __sched wait_for_completion_killable(struct completion *x)

{
@@ -4874,6 +4884,9 @@ EXPORT_SYMBOL(wait_for_completion_killable); 
 * This waits for either a completion of a specific task to be

 * signaled or for a specified timeout to expire. It can be

 * interrupted by a kill signal. The timeout is in jiffies.

 *

 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,

 * positive (at least 1, or number of jiffies left till timeout) if completed.

 */

long __sched

wait_for_completion_killable_timeout(struct completion *x,