linux-kernel - [PATCH] kernel/futex.c: notice the return value after rt_mutex_finish_proxy

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Message-ID: <5212DD71.7070208@asianux.com>
Date:	Tue, 20 Aug 2013 11:07:29 +0800
From:	Chen Gang <gang.chen@...anux.com>
To:	Thomas Gleixner <tglx@...utronix.de>, dvhart@...ux.intel.com,
	ccross@...roid.com, Mel Gorman <mgorman@...e.de>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] kernel/futex.c: notice the return value after rt_mutex_finish_proxy_lock()
 fails

rt_mutex_finish_proxy_lock() can return failure code (e.g. -EINTR,
-ETIMEDOUT).

Original implementation has already noticed about it, but not check it
before next work.

Also let coments within 80 columns to pass "./scripts/checkpatch.pl".


Signed-off-by: Chen Gang <gang.chen@...anux.com>
---
 kernel/futex.c |   30 ++++++++++++++++--------------
 1 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index c3a1a55..1a94e7d 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2373,21 +2373,23 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 		ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter, 1);
 		debug_rt_mutex_free_waiter(&rt_waiter);
 
-		spin_lock(q.lock_ptr);
-		/*
-		 * Fixup the pi_state owner and possibly acquire the lock if we
-		 * haven't already.
-		 */
-		res = fixup_owner(uaddr2, &q, !ret);
-		/*
-		 * If fixup_owner() returned an error, proprogate that.  If it
-		 * acquired the lock, clear -ETIMEDOUT or -EINTR.
-		 */
-		if (res)
-			ret = (res < 0) ? res : 0;
+		if (!ret) {
+			spin_lock(q.lock_ptr);
+			/*
+			 * Fixup the pi_state owner and possibly acquire the
+			 * lock if we haven't already.
+			 */
+			res = fixup_owner(uaddr2, &q, !ret);
+			/*
+			 * If fixup_owner() returned an error, proprogate that.
+			 * If it acquired the lock, clear -ETIMEDOUT or -EINTR.
+			 */
+			if (res)
+				ret = (res < 0) ? res : 0;
 
-		/* Unqueue and drop the lock. */
-		unqueue_me_pi(&q);
+			/* Unqueue and drop the lock. */
+			unqueue_me_pi(&q);
+		}
 	}
 
 	/*
-- 
1.7.7.6
--
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