From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758745Ab1JFTWz (ORCPT ); Thu, 6 Oct 2011 15:22:55 -0400 Received: from fieldses.org ([174.143.236.118]:50105 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758646Ab1JFTWy (ORCPT ); Thu, 6 Oct 2011 15:22:54 -0400 Date: Thu, 6 Oct 2011 15:22:46 -0400 To: Ingo Molnar , Peter Zijlstra Cc: linux-kernel@vger.kernel.org Subject: [PATCH] sched: document wait_for_completion_* return values Message-ID: <20111006192246.GB28026@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) From: "J. Bruce Fields" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: J. Bruce Fields 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 --- kernel/sched.c | 13 +++++++++++++ 1 files changed, 13 insertions(+), 0 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index ccacdbd..ee84344 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4690,6 +4690,9 @@ 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) @@ -4704,6 +4707,8 @@ 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) { @@ -4721,6 +4726,9 @@ 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, @@ -4736,6 +4744,8 @@ 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) { @@ -4754,6 +4764,9 @@ 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, -- 1.7.4.1