Merge branch 'tip/futex/devel' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-rt into core/futexes

 futex,plist: Pass the real head of the priority list to plist_del()
 futex,plist: Remove debug lock assignment from plist_node
 plist: Shrink struct plist_head
 plist: Add priority list test

1 files changed, 23 insertions, 17 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index 237f14bfc022..c6bef6e404fe 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -772,6 +772,24 @@ retry:
         return ret;
 }
 
+/**
+ * __unqueue_futex() - Remove the futex_q from its futex_hash_bucket
+ * @q:  The futex_q to unqueue
+ *
+ * The q->lock_ptr must not be NULL and must be held by the caller.
+ */
+static void __unqueue_futex(struct futex_q *q)
+{
+        struct futex_hash_bucket *hb;
+
+        if (WARN_ON(!q->lock_ptr || !spin_is_locked(q->lock_ptr)
+                        || plist_node_empty(&q->list)))
+                return;
+
+        hb = container_of(q->lock_ptr, struct futex_hash_bucket, lock);
+        plist_del(&q->list, &hb->chain);
+}
+
 /*
  * The hash bucket lock must be held when this is called.
  * Afterwards, the futex_q must not be accessed.
@@ -789,7 +807,7 @@ static void wake_futex(struct futex_q *q)
          */
         get_task_struct(p);
 
-        plist_del(&q->list, &q->list.plist);
+        __unqueue_futex(q);
         /*
          * The waiting task can free the futex_q as soon as
          * q->lock_ptr = NULL is written, without taking any locks. A
@@ -1064,9 +1082,6 @@ void requeue_futex(struct futex_q *q, struct futex_hash_bucket *hb1,
                 plist_del(&q->list, &hb1->chain);
                 plist_add(&q->list, &hb2->chain);
                 q->lock_ptr = &hb2->lock;
-#ifdef CONFIG_DEBUG_PI_LIST
-                q->list.plist.spinlock = &hb2->lock;
-#endif
         }
         get_futex_key_refs(key2);
         q->key = *key2;
@@ -1093,16 +1108,12 @@ void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key,
         get_futex_key_refs(key);
         q->key = *key;
 
-        WARN_ON(plist_node_empty(&q->list));
-        plist_del(&q->list, &q->list.plist);
+        __unqueue_futex(q);
 
         WARN_ON(!q->rt_waiter);
         q->rt_waiter = NULL;
 
         q->lock_ptr = &hb->lock;
-#ifdef CONFIG_DEBUG_PI_LIST
-        q->list.plist.spinlock = &hb->lock;
-#endif
 
         wake_up_state(q->task, TASK_NORMAL);
 }
@@ -1450,9 +1461,6 @@ static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb)
         prio = min(current->normal_prio, MAX_RT_PRIO);
 
         plist_node_init(&q->list, prio);
-#ifdef CONFIG_DEBUG_PI_LIST
-        q->list.plist.spinlock = &hb->lock;
-#endif
         plist_add(&q->list, &hb->chain);
         q->task = current;
         spin_unlock(&hb->lock);
@@ -1497,8 +1505,7 @@ retry:
                         spin_unlock(lock_ptr);
                         goto retry;
                 }
-                WARN_ON(plist_node_empty(&q->list));
-                plist_del(&q->list, &q->list.plist);
+                __unqueue_futex(q);
 
                 BUG_ON(q->pi_state);
 
@@ -1518,8 +1525,7 @@ retry:
 static void unqueue_me_pi(struct futex_q *q)
         __releases(q->lock_ptr)
 {
-        WARN_ON(plist_node_empty(&q->list));
-        plist_del(&q->list, &q->list.plist);
+        __unqueue_futex(q);
 
         BUG_ON(!q->pi_state);
         free_pi_state(q->pi_state);
@@ -2156,7 +2162,7 @@ int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb,
                  * We were woken prior to requeue by a timeout or a signal.
                  * Unqueue the futex_q and determine which it was.
                  */
-                plist_del(&q->list, &q->list.plist);
+                plist_del(&q->list, &hb->chain);
 
                 /* Handle spurious wakeups gracefully */
                 ret = -EWOULDBLOCK;