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>

1 files changed, 13 insertions, 25 deletions

diff --git a/ipc/sem.c b/ipc/sem.c
index 084e1f55ca72..4f5af6e7d630 100644
--- 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