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>
diff --git a/ipc/sem.c b/ipc/sem.c
index 5cf7b4c..8f5aa34 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -322,7 +322,6 @@
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 @@
return -ENOMEM;
}
+ rcu_read_lock();
sem_lock_and_putref(sma);
if (sma->sem_perm.deleted) {
sem_unlock(sma, -1);
@@ -1166,6 +1166,7 @@
goto out_free;
}
}
+ rcu_read_lock();
sem_lock_and_putref(sma);
if (sma->sem_perm.deleted) {
sem_unlock(sma, -1);
@@ -1451,7 +1452,7 @@
}
/* 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);