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| author | J. Bruce Fields <bfields@redhat.com> | 2011-10-06 15:22:46 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-11-14 12:50:37 +0100 |
| commit | c6dc7f055d333ef35f397b8d7c3abcd1918bf8cb (patch) | |
| tree | c4edc4a84ba9636057d923a308e2a3bcd910fa63 | |
| parent | 461819ac8ee950ce027c72a066156a3df9e60c7e (diff) | |
| download | linux-c6dc7f055d333ef35f397b8d7c3abcd1918bf8cb.tar.bz2 | |
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: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111006192246.GB28026@fieldses.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 0e9344a71be3..3d2c436959a1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -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, |