]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
ipc/sem.c: bugfix for semop() not reporting successful operation
authorManfred Spraul <manfred@colorfullife.com>
Tue, 20 Jul 2010 20:24:23 +0000 (13:24 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 20 Jul 2010 23:25:40 +0000 (16:25 -0700)
commitc61284e99191b2284fb74dae6961d4d09e4e59e8
tree6b49a9e2e5ade9f395c66f6453ff60b952a6df38
parent19f0f0af097ba3138ae2780b471180512763a78f
ipc/sem.c: bugfix for semop() not reporting successful operation

The last change to improve the scalability moved the actual wake-up out of
the section that is protected by spin_lock(sma->sem_perm.lock).

This means that IN_WAKEUP can be in queue.status even when the spinlock is
acquired by the current task.  Thus the same loop that is performed when
queue.status is read without the spinlock acquired must be performed when
the spinlock is acquired.

Thanks to kamezawa.hiroyu@jp.fujitsu.com for noticing lack of the memory
barrier.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=16255

[akpm@linux-foundation.org: clean up kerneldoc, checkpatch warning and whitespace]
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Reported-by: Luca Tettamanti <kronos.it@gmail.com>
Tested-by: Luca Tettamanti <kronos.it@gmail.com>
Reported-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Maciej Rutecki <maciej.rutecki@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc/sem.c