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authorLinus Torvalds <torvalds@linux-foundation.org>2013-05-04 10:13:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-05-04 17:19:39 -0700
commit4091fd942e96af5a0b1dfa6aac5f44153ebf7cdb (patch)
tree0455a439ad1a9884018286670e49c4e18cfaa359 /ipc
parent73b29505c36eeb4751eccad41f6aad78562521f8 (diff)
downloadlinux-4091fd942e96af5a0b1dfa6aac5f44153ebf7cdb.tar.gz
ipc: move the rcu_read_lock() from sem_lock_and_putref() into callers
This is another ipc semaphore locking cleanup, trying to make the locking more straightforward. We move the rcu read locking into the callers of sem_lock_and_putref(), which in general means that we now mostly do the rcu_read_lock() and rcu_read_unlock() in the same function. Mostly. We still have the ipc_addid/newary/freeary mess, and things like ipcctl_pre_down_nolock(). Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/sem.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/ipc/sem.c b/ipc/sem.c
index 5cf7b4c093b..8f5aa34f8d3 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -322,7 +322,6 @@ static inline struct sem_array *sem_obtain_object_check(struct ipc_namespace *ns
static inline void sem_lock_and_putref(struct sem_array *sma)
{
- rcu_read_lock();
sem_lock(sma, NULL, -1);
ipc_rcu_putref(sma);
}
@@ -1117,6 +1116,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
return -ENOMEM;
}
+ rcu_read_lock();
sem_lock_and_putref(sma);
if (sma->sem_perm.deleted) {
sem_unlock(sma, -1);
@@ -1166,6 +1166,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
goto out_free;
}
}
+ rcu_read_lock();
sem_lock_and_putref(sma);
if (sma->sem_perm.deleted) {
sem_unlock(sma, -1);
@@ -1451,7 +1452,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
}
/* step 3: Acquire the lock on semaphore array */
- /* This also does the rcu_read_lock() */
+ rcu_read_lock();
sem_lock_and_putref(sma);
if (sma->sem_perm.deleted) {
sem_unlock(sma, -1);