ipc,shm: make shmctl_nolock lockless
authorDavidlohr Bueso <davidlohr.bueso@hp.com>
Wed, 11 Sep 2013 21:26:20 +0000 (14:26 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 18 Oct 2013 14:45:47 +0000 (07:45 -0700)
commitc29c40392a01b9414b02c1b57b042950704cb774
treedd08fdda23b257a425e33aac9c3688e0ed02101f
parentd6187ddfc90715e95b8c73f49887781b4b2a1ebc
ipc,shm: make shmctl_nolock lockless

commit c97cb9ccab8c85428ec21eff690642ad2ce1fa8a upstream.

While the INFO cmd doesn't take the ipc lock, the STAT commands do acquire
it unnecessarily.  We can do the permissions and security checks only
holding the rcu lock.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ipc/shm.c