Revert 337f13046ff0 ("futex: Allow FUTEX_CLOCK_REALTIME with FUTEX_WAIT op")

[linux-2.6-microblaze.git] / kernel / futex.c

diff --git a/kernel/futex.c b/kernel/futex.c
index 00febd6..4740200 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -981,6 +981,7 @@ static inline void exit_pi_state_list(struct task_struct *curr) { }
  * p->pi_lock:
  *
  *     p->pi_state_list -> pi_state->list, relation
+ *     pi_mutex->owner -> pi_state->owner, relation
  *
  * pi_state->refcount:
  *
@@ -1494,13 +1495,14 @@ static void mark_wake_futex(struct wake_q_head *wake_q, struct futex_q *q)
 static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_state)
 {
        u32 curval, newval;
+       struct rt_mutex_waiter *top_waiter;
        struct task_struct *new_owner;
        bool postunlock = false;
        DEFINE_WAKE_Q(wake_q);
        int ret = 0;
 
-       new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
-       if (WARN_ON_ONCE(!new_owner)) {
+       top_waiter = rt_mutex_top_waiter(&pi_state->pi_mutex);
+       if (WARN_ON_ONCE(!top_waiter)) {
                /*
                 * As per the comment in futex_unlock_pi() this should not happen.
                 *
@@ -1513,6 +1515,8 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_
                goto out_unlock;
        }
 
+       new_owner = top_waiter->task;
+
        /*
         * We pass it to the next owner. The WAITERS bit is always kept
         * enabled while there is PI state around. We cleanup the owner
@@ -2315,19 +2319,15 @@ retry:
 
 /*
  * PI futexes can not be requeued and must remove themself from the
- * hash bucket. The hash bucket lock (i.e. lock_ptr) is held on entry
- * and dropped here.
+ * hash bucket. The hash bucket lock (i.e. lock_ptr) is held.
  */
 static void unqueue_me_pi(struct futex_q *q)
-       __releases(q->lock_ptr)
 {
        __unqueue_futex(q);
 
        BUG_ON(!q->pi_state);
        put_pi_state(q->pi_state);
        q->pi_state = NULL;
-
-       spin_unlock(q->lock_ptr);
 }
 
 static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
@@ -2909,8 +2909,8 @@ no_block:
        if (res)
                ret = (res < 0) ? res : 0;
 
-       /* Unqueue and drop the lock */
        unqueue_me_pi(&q);
+       spin_unlock(q.lock_ptr);
        goto out;
 
 out_unlock_put_key:
@@ -3237,15 +3237,14 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
         * reference count.
         */
 
-       /* Check if the requeue code acquired the second futex for us. */
+       /*
+        * Check if the requeue code acquired the second futex for us and do
+        * any pertinent fixup.
+        */
        if (!q.rt_waiter) {
-               /*
-                * Got the lock. We might not be the anticipated owner if we
-                * did a lock-steal - fix up the PI-state in that case.
-                */
                if (q.pi_state && (q.pi_state->owner != current)) {
                        spin_lock(q.lock_ptr);
-                       ret = fixup_pi_state_owner(uaddr2, &q, current);
+                       ret = fixup_owner(uaddr2, &q, true);
                        /*
                         * Drop the reference to the pi state which
                         * the requeue_pi() code acquired for us.
@@ -3287,8 +3286,8 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
                if (res)
                        ret = (res < 0) ? res : 0;
 
-               /* Unqueue and drop the lock. */
                unqueue_me_pi(&q);
+               spin_unlock(q.lock_ptr);
        }
 
        if (ret == -EINTR) {
@@ -3711,8 +3710,7 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 
        if (op & FUTEX_CLOCK_REALTIME) {
                flags |= FLAGS_CLOCKRT;
-               if (cmd != FUTEX_WAIT && cmd != FUTEX_WAIT_BITSET && \
-                   cmd != FUTEX_WAIT_REQUEUE_PI)
+               if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI)
                        return -ENOSYS;
        }