4 files changed, 25 insertions, 18 deletions
diff --git a/kernel/futex/core.c b/kernel/futex/core.c
index ebdd76b4ecbb..cca15859a50b 100644
--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c
@@ -50,10 +50,10 @@
  */
 static struct {
 	struct futex_hash_bucket *queues;
-	unsigned long            hashsize;
+	unsigned long            hashmask;
 } __futex_data __read_mostly __aligned(2*sizeof(long));
 #define futex_queues   (__futex_data.queues)
-#define futex_hashsize (__futex_data.hashsize)
+#define futex_hashmask (__futex_data.hashmask)
 
 
 /*
@@ -119,7 +119,7 @@ struct futex_hash_bucket *futex_hash(union futex_key *key)
 	u32 hash = jhash2((u32 *)key, offsetof(typeof(*key), both.offset) / 4,
 			  key->both.offset);
 
-	return &futex_queues[hash & (futex_hashsize - 1)];
+	return &futex_queues[hash & futex_hashmask];
 }
 
 
@@ -532,7 +532,8 @@ void futex_q_unlock(struct futex_hash_bucket *hb)
 	futex_hb_waiters_dec(hb);
 }
 
-void __futex_queue(struct futex_q *q, struct futex_hash_bucket *hb)
+void __futex_queue(struct futex_q *q, struct futex_hash_bucket *hb,
+		   struct task_struct *task)
 {
 	int prio;
 
@@ -548,7 +549,7 @@ void __futex_queue(struct futex_q *q, struct futex_hash_bucket *hb)
 
 	plist_node_init(&q->list, prio);
 	plist_add(&q->list, &hb->chain);
-	q->task = current;
+	q->task = task;
 }
 
 /**
@@ -1126,27 +1127,28 @@ void futex_exit_release(struct task_struct *tsk)
 
 static int __init futex_init(void)
 {
+	unsigned long hashsize, i;
 	unsigned int futex_shift;
-	unsigned long i;
 
 #ifdef CONFIG_BASE_SMALL
-	futex_hashsize = 16;
+	hashsize = 16;
 #else
-	futex_hashsize = roundup_pow_of_two(256 * num_possible_cpus());
+	hashsize = roundup_pow_of_two(256 * num_possible_cpus());
 #endif
 
 	futex_queues = alloc_large_system_hash("futex", sizeof(*futex_queues),
-					       futex_hashsize, 0, 0,
+					       hashsize, 0, 0,
 					       &futex_shift, NULL,
-					       futex_hashsize, futex_hashsize);
-	futex_hashsize = 1UL << futex_shift;
+					       hashsize, hashsize);
+	hashsize = 1UL << futex_shift;
 
-	for (i = 0; i < futex_hashsize; i++) {
+	for (i = 0; i < hashsize; i++) {
 		atomic_set(&futex_queues[i].waiters, 0);
 		plist_head_init(&futex_queues[i].chain);
 		spin_lock_init(&futex_queues[i].lock);
 	}
 
+	futex_hashmask = hashsize - 1;
 	return 0;
 }
 core_initcall(futex_init);
diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
index 99b32e728c4a..6b2f4c7eb720 100644
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -285,13 +285,15 @@ static inline int futex_get_value_locked(u32 *dest, u32 __user *from)
 }
 
 extern void __futex_unqueue(struct futex_q *q);
-extern void __futex_queue(struct futex_q *q, struct futex_hash_bucket *hb);
+extern void __futex_queue(struct futex_q *q, struct futex_hash_bucket *hb,
+				struct task_struct *task);
 extern int futex_unqueue(struct futex_q *q);
 
 /**
  * futex_queue() - Enqueue the futex_q on the futex_hash_bucket
  * @q:	The futex_q to enqueue
  * @hb:	The destination hash bucket
+ * @task: Task queueing this futex
  *
  * The hb->lock must be held by the caller, and is released here. A call to
  * futex_queue() is typically paired with exactly one call to futex_unqueue().  The
@@ -299,11 +301,14 @@ extern int futex_unqueue(struct futex_q *q);
  * or nothing if the unqueue is done as part of the wake process and the unqueue
  * state is implicit in the state of woken task (see futex_wait_requeue_pi() for
  * an example).
+ *
+ * Note that @task may be NULL, for async usage of futexes.
  */
-static inline void futex_queue(struct futex_q *q, struct futex_hash_bucket *hb)
+static inline void futex_queue(struct futex_q *q, struct futex_hash_bucket *hb,
+			       struct task_struct *task)
 	__releases(&hb->lock)
 {
-	__futex_queue(q, hb);
+	__futex_queue(q, hb, task);
 	spin_unlock(&hb->lock);
 }
 
diff --git a/kernel/futex/pi.c b/kernel/futex/pi.c
index daea650b16f5..7a941845f7ee 100644
--- a/kernel/futex/pi.c
+++ b/kernel/futex/pi.c
@@ -982,7 +982,7 @@ retry_private:
 	/*
 	 * Only actually queue now that the atomic ops are done:
 	 */
-	__futex_queue(&q, hb);
+	__futex_queue(&q, hb, current);
 
 	if (trylock) {
 		ret = rt_mutex_futex_trylock(&q.pi_state->pi_mutex);
diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c
index eb86a7ade06a..25877d4f2f8f 100644
--- a/kernel/futex/waitwake.c
+++ b/kernel/futex/waitwake.c
@@ -349,7 +349,7 @@ void futex_wait_queue(struct futex_hash_bucket *hb, struct futex_q *q,
 	 * access to the hash list and forcing another memory barrier.
 	 */
 	set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
-	futex_queue(q, hb);
+	futex_queue(q, hb, current);
 
 	/* Arm the timer */
 	if (timeout)
@@ -460,7 +460,7 @@ retry:
 			 * next futex. Queue each futex at this moment so hb can
 			 * be unlocked.
 			 */
-			futex_queue(q, hb);
+			futex_queue(q, hb, current);
 			continue;
 		}