From: Wolfram Sang Date: Tue, 4 Nov 2014 11:01:41 +0000 (+0100) Subject: sched/completion: Document when to use wait_for_completion_io_*() X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=a1bd5373357d3edc4b97548747d583c3efa484b3;p=openwrt%2Fstaging%2Fblogic.git sched/completion: Document when to use wait_for_completion_io_*() As discussed in [1], accounting IO is meant for blkio only. Document that so driver authors won't use them for device io. [1] http://thread.gmane.org/gmane.linux.drivers.i2c/20470 Signed-off-by: Wolfram Sang Signed-off-by: Peter Zijlstra (Intel) Cc: One Thousand Gnomes Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1415098901-2768-1-git-send-email-wsa@the-dreams.de Signed-off-by: Ingo Molnar --- diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c index a63f4dc27909..607f852b4d04 100644 --- a/kernel/sched/completion.c +++ b/kernel/sched/completion.c @@ -148,7 +148,7 @@ EXPORT_SYMBOL(wait_for_completion_timeout); * * This waits to be signaled for completion of a specific task. It is NOT * interruptible and there is no timeout. The caller is accounted as waiting - * for IO. + * for IO (which traditionally means blkio only). */ void __sched wait_for_completion_io(struct completion *x) { @@ -163,7 +163,8 @@ EXPORT_SYMBOL(wait_for_completion_io); * * 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 caller is accounted as waiting for IO. + * interruptible. The caller is accounted as waiting for IO (which traditionally + * means blkio only). * * Return: 0 if timed out, and positive (at least 1, or number of jiffies left * till timeout) if completed.