linux/ipc
Davidlohr Bueso 4d2bff5eb8 ipc: introduce obtaining a lockless ipc object
Through ipc_lock() and therefore ipc_lock_check() we currently return the
locked ipc object.  This is not necessary for all situations and can,
therefore, cause unnecessary ipc lock contention.

Introduce analogous ipc_obtain_object() and ipc_obtain_object_check()
functions that only lookup and return the ipc object.

Both these functions must be called within the RCU read critical section.

[akpm@linux-foundation.org: propagate the ipc_obtain_object() errno from ipc_lock()]
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Chegu Vinod <chegu_vinod@hp.com>
Acked-by: Michel Lespinasse <walken@google.com>
Cc: Emmanuel Benisty <benisty.e@gmail.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-01 08:12:57 -07:00
..
Makefile
compat.c get rid of union semop in sys_semctl(2) arguments 2013-03-05 15:14:16 -05:00
compat_mq.c
ipc_sysctl.c ipc: add sysctl to specify desired next object id 2013-01-04 16:11:45 -08:00
ipcns_notifier.c
mq_sysctl.c mqueue: separate mqueue default value from maximum value 2012-05-31 17:49:31 -07:00
mqueue.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-03-28 13:43:46 -07:00
msg.c ipc: refactor msg list search into separate function 2013-05-01 08:12:57 -07:00
msgutil.c ipc/msgutil.c: use linux/uaccess.h 2013-05-01 08:12:57 -07:00
namespace.c userns: Require CAP_SYS_ADMIN for most uses of setns. 2012-12-14 16:12:03 -08:00
sem.c get rid of union semop in sys_semctl(2) arguments 2013-03-05 15:14:16 -05:00
shm.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
syscall.c get rid of union semop in sys_semctl(2) arguments 2013-03-05 15:14:16 -05:00
util.c ipc: introduce obtaining a lockless ipc object 2013-05-01 08:12:57 -07:00
util.h ipc: introduce obtaining a lockless ipc object 2013-05-01 08:12:57 -07:00