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author | Davidlohr Bueso <dave@stgolabs.net> | 2016-12-15 02:06:49 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-15 03:04:08 +0300 |
commit | 370b262c896e5565b271a3ea3abee4d0914ba443 (patch) | |
tree | 7463704f20a1f8d00d717b34ca77a95b56a774fe /drivers/infiniband | |
parent | b5fa01a22e4ba9e3ca6de7cb94c3d21e42da449c (diff) | |
download | linux-370b262c896e5565b271a3ea3abee4d0914ba443.tar.xz |
ipc/sem: avoid idr tree lookup for interrupted semop
We can avoid the idr tree lookup (albeit possibly avoiding
idr_find_fast()) when being awoken in EINTR, as the semid will not
change in this context while blocked. Use the sma pointer directly and
take the sem_lock, then re-check for RMID races. We continue to
re-check the queue.status with the lock held such that we can detect
situations where we where are dealing with a spurious wakeup but another
task that holds the sem_lock updated the queue.status while we were
spinning for it. Once we take the lock it obviously won't change again.
Being the only caller, get rid of sem_obtain_lock() altogether.
Link: http://lkml.kernel.org/r/1478708774-28826-3-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/infiniband')
0 files changed, 0 insertions, 0 deletions