linux/ipc
Davidlohr Bueso 370b262c89 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>
2016-12-14 16:04:08 -08:00
..
compat_mq.c ipc, kernel: use Linux headers 2014-06-06 16:08:14 -07:00
compat.c ipc: resolve shadow warnings 2014-10-14 02:18:23 +02:00
ipc_sysctl.c ipc/msg: increase MSGMNI, remove scaling 2014-12-13 12:42:52 -08:00
Makefile ipc/msg: increase MSGMNI, remove scaling 2014-12-13 12:42:52 -08:00
mq_sysctl.c ipc: convert use of typedef ctl_table to struct ctl_table 2014-06-06 16:08:16 -07:00
mqueue.c sched/wake_q: Rename WAKE_Q to DEFINE_WAKE_Q 2016-11-21 10:29:01 +01:00
msg.c ipc: msg, make msgrcv work with LONG_MIN 2016-12-14 16:04:08 -08:00
msgutil.c ipc: account for kmem usage on mqueue and msg 2016-10-27 18:43:43 -07:00
namespace.c Merge branch 'nsfs-ioctls' into HEAD 2016-09-22 20:00:36 -05:00
sem.c ipc/sem: avoid idr tree lookup for interrupted semop 2016-12-14 16:04:08 -08:00
shm.c ipc/shm.c: coding style fixes 2016-12-14 16:04:08 -08:00
syscall.c get rid of union semop in sys_semctl(2) arguments 2013-03-05 15:14:16 -05:00
util.c tree wide: use kvfree() than conditional kfree()/vfree() 2016-01-22 17:02:18 -08:00
util.h tree wide: use kvfree() than conditional kfree()/vfree() 2016-01-22 17:02:18 -08:00