ipc/sem: use proper list api for pending_list wakeups

... saves some LoC and looks cleaner than re-implementing the calls.

Link: http://lkml.kernel.org/r/1474225896-10066-6-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/ipc/sem.c b/ipc/sem.c
index 084e1f55ca72ade99873154dff5e5bb4eac1da95..4f5af6e7d6303586f3496de736007ced7cb7a9d2 100644 (file)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -813,8 +813,7 @@ static inline int check_restart(struct sem_array *sma, struct sem_queue *q)
 static int wake_const_ops(struct sem_array *sma, int semnum,
                          struct wake_q_head *wake_q)
 {
-       struct sem_queue *q;
-       struct list_head *walk;
+       struct sem_queue *q, *tmp;
        struct list_head *pending_list;
        int semop_completed = 0;
 
@@ -823,25 +822,19 @@ static int wake_const_ops(struct sem_array *sma, int semnum,
        else
                pending_list = &sma->sem_base[semnum].pending_const;
 
-       walk = pending_list->next;
-       while (walk != pending_list) {
-               int error;
-
-               q = container_of(walk, struct sem_queue, list);
-               walk = walk->next;
-
-               error = perform_atomic_semop(sma, q);
-
-               if (error <= 0) {
-                       /* operation completed, remove from queue & wakeup */
+       list_for_each_entry_safe(q, tmp, pending_list, list) {
+               int error = perform_atomic_semop(sma, q);
 
-                       unlink_queue(sma, q);
+               if (error > 0)
+                       continue;
+               /* operation completed, remove from queue & wakeup */
+               unlink_queue(sma, q);
 
-                       wake_up_sem_queue_prepare(q, error, wake_q);
-                       if (error == 0)
-                               semop_completed = 1;
-               }
+               wake_up_sem_queue_prepare(q, error, wake_q);
+               if (error == 0)
+                       semop_completed = 1;
        }
+
        return semop_completed;
 }
 
@@ -914,8 +907,7 @@ static int do_smart_wakeup_zero(struct sem_array *sma, struct sembuf *sops,
  */
 static int update_queue(struct sem_array *sma, int semnum, struct wake_q_head *wake_q)
 {
-       struct sem_queue *q;
-       struct list_head *walk;
+       struct sem_queue *q, *tmp;
        struct list_head *pending_list;
        int semop_completed = 0;
 
@@ -925,13 +917,9 @@ static int update_queue(struct sem_array *sma, int semnum, struct wake_q_head *w
                pending_list = &sma->sem_base[semnum].pending_alter;
 
 again:
-       walk = pending_list->next;
-       while (walk != pending_list) {
+       list_for_each_entry_safe(q, tmp, pending_list, list) {
                int error, restart;
 
-               q = container_of(walk, struct sem_queue, list);
-               walk = walk->next;
-
                /* If we are scanning the single sop, per-semaphore list of
                 * one semaphore and that semaphore is 0, then it is not
                 * necessary to scan further: simple increments