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authorDavidlohr Bueso <dave@stgolabs.net>2016-12-14 15:06:31 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-14 16:04:08 -0800
commit248e7357cf8ec50bdaca68dce7c488ce843b6b93 (patch)
tree54ea60ba6f92ee99014c0b565ab87150eb930067 /ipc
parent7a5c8b57cec93196b3e84e3cad2ff81ae0faed78 (diff)
ipc/sem: do not call wake_sem_queue_do() prematurely ... as this call should obviously be paired with its _prepare()
counterpart. At least whenever possible, as there is no harm in calling it bogusly as we do now in a few places. Immediate error semop(2) paths that are far from ever having the task block can be simplified and avoid a few unnecessary loads on their way out of the call as it is not deeply nested. Link: http://lkml.kernel.org/r/1474225896-10066-2-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 'ipc')
-rw-r--r--ipc/sem.c19
1 files changed, 12 insertions, 7 deletions
diff --git a/ipc/sem.c b/ipc/sem.c
index 10b94bc59d4a..b33dd98fde69 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -1887,16 +1887,22 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
}
error = -EFBIG;
- if (max >= sma->sem_nsems)
- goto out_rcu_wakeup;
+ if (max >= sma->sem_nsems) {
+ rcu_read_unlock();
+ goto out_free;
+ }
error = -EACCES;
- if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO))
- goto out_rcu_wakeup;
+ if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO)) {
+ rcu_read_unlock();
+ goto out_free;
+ }
error = security_sem_semop(sma, sops, nsops, alter);
- if (error)
- goto out_rcu_wakeup;
+ if (error) {
+ rcu_read_unlock();
+ goto out_free;
+ }
error = -EIDRM;
locknum = sem_lock(sma, sops, nsops);
@@ -2039,7 +2045,6 @@ sleep_again:
out_unlock_free:
sem_unlock(sma, locknum);
-out_rcu_wakeup:
rcu_read_unlock();
wake_up_sem_queue_do(&tasks);
out_free:

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