diff options
author | Jianyu Zhan <nasa4836@gmail.com> | 2016-03-07 09:32:24 +0800 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2016-03-08 17:04:02 +0100 |
commit | 29b75eb2d56a714190a93d7be4525e617591077a (patch) | |
tree | 07f13028b74665bf757523864dc2478426974c54 /arch | |
parent | 9e4e7554e755aaad8df0e26268787438735b4b76 (diff) |
futex: Replace barrier() in unqueue_me() with READ_ONCE()
Commit e91467ecd1ef ("bug in futex unqueue_me") introduced a barrier() in
unqueue_me() to prevent the compiler from rereading the lock pointer which
might change after a check for NULL.
Replace the barrier() with a READ_ONCE() for the following reasons:
1) READ_ONCE() is a weaker form of barrier() that affects only the specific
load operation, while barrier() is a general compiler level memory barrier.
READ_ONCE() was not available at the time when the barrier was added.
2) Aside of that READ_ONCE() is descriptive and self explainatory while a
barrier without comment is not clear to the casual reader.
No functional change.
[ tglx: Massaged changelog ]
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Cc: dave@stgolabs.net
Cc: peterz@infradead.org
Cc: linux@rasmusvillemoes.dk
Cc: akpm@linux-foundation.org
Cc: fengguang.wu@intel.com
Cc: bigeasy@linutronix.de
Link: http://lkml.kernel.org/r/1457314344-5685-1-git-send-email-nasa4836@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
0 files changed, 0 insertions, 0 deletions