PCI/PM: Fix fallback to PCI_D0 in pci_platform_power_transition()

[pandora-kernel.git] / kernel / futex.c

diff --git a/kernel/futex.c b/kernel/futex.c
index 80fb1c6..77bccfc 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -716,7 +716,7 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb,
                                struct futex_pi_state **ps,
                                struct task_struct *task, int set_waiters)
 {
-       int lock_taken, ret, ownerdied = 0;
+       int lock_taken, ret, force_take = 0;
        u32 uval, newval, curval, vpid = task_pid_vnr(task);
 
 retry:
@@ -755,17 +755,15 @@ retry:
        newval = curval | FUTEX_WAITERS;
 
        /*
-        * There are two cases, where a futex might have no owner (the
-        * owner TID is 0): OWNER_DIED. We take over the futex in this
-        * case. We also do an unconditional take over, when the owner
-        * of the futex died.
-        *
-        * This is safe as we are protected by the hash bucket lock !
+        * Should we force take the futex? See below.
         */
-       if (unlikely(ownerdied || !(curval & FUTEX_TID_MASK))) {
-               /* Keep the OWNER_DIED bit */
+       if (unlikely(force_take)) {
+               /*
+                * Keep the OWNER_DIED and the WAITERS bit and set the
+                * new TID value.
+                */
                newval = (curval & ~FUTEX_TID_MASK) | vpid;
-               ownerdied = 0;
+               force_take = 0;
                lock_taken = 1;
        }
 
@@ -775,7 +773,7 @@ retry:
                goto retry;
 
        /*
-        * We took the lock due to owner died take over.
+        * We took the lock due to forced take over.
         */
        if (unlikely(lock_taken))
                return 1;
@@ -790,20 +788,25 @@ retry:
                switch (ret) {
                case -ESRCH:
                        /*
-                        * No owner found for this futex. Check if the
-                        * OWNER_DIED bit is set to figure out whether
-                        * this is a robust futex or not.
+                        * We failed to find an owner for this
+                        * futex. So we have no pi_state to block
+                        * on. This can happen in two cases:
+                        *
+                        * 1) The owner died
+                        * 2) A stale FUTEX_WAITERS bit
+                        *
+                        * Re-read the futex value.
                         */
                        if (get_futex_value_locked(&curval, uaddr))
                                return -EFAULT;
 
                        /*
-                        * We simply start over in case of a robust
-                        * futex. The code above will take the futex
-                        * and return happy.
+                        * If the owner died or we have a stale
+                        * WAITERS bit the owner TID in the user space
+                        * futex is 0.
                         */
-                       if (curval & FUTEX_OWNER_DIED) {
-                               ownerdied = 1;
+                       if (!(curval & FUTEX_TID_MASK)) {
+                               force_take = 1;
                                goto retry;
                        }
                default:
@@ -840,6 +843,9 @@ static void wake_futex(struct futex_q *q)
 {
        struct task_struct *p = q->task;
 
+       if (WARN(q->pi_state || q->rt_waiter, "refusing to wake PI futex\n"))
+               return;
+
        /*
         * We set q->lock_ptr = NULL _before_ we wake up the task. If
         * a non-futex wake up happens on another CPU then the task
@@ -1075,6 +1081,10 @@ retry_private:
 
        plist_for_each_entry_safe(this, next, head, list) {
                if (match_futex (&this->key, &key1)) {
+                       if (this->pi_state || this->rt_waiter) {
+                               ret = -EINVAL;
+                               goto out_unlock;
+                       }
                        wake_futex(this);
                        if (++ret >= nr_wake)
                                break;
@@ -1087,6 +1097,10 @@ retry_private:
                op_ret = 0;
                plist_for_each_entry_safe(this, next, head, list) {
                        if (match_futex (&this->key, &key2)) {
+                               if (this->pi_state || this->rt_waiter) {
+                                       ret = -EINVAL;
+                                       goto out_unlock;
+                               }
                                wake_futex(this);
                                if (++op_ret >= nr_wake2)
                                        break;
@@ -1095,6 +1109,7 @@ retry_private:
                ret += op_ret;
        }
 
+out_unlock:
        double_unlock_hb(hb1, hb2);
 out_put_keys:
        put_futex_key(&key2);
@@ -1384,9 +1399,13 @@ retry_private:
                /*
                 * FUTEX_WAIT_REQEUE_PI and FUTEX_CMP_REQUEUE_PI should always
                 * be paired with each other and no other futex ops.
+                *
+                * We should never be requeueing a futex_q with a pi_state,
+                * which is awaiting a futex_unlock_pi().
                 */
                if ((requeue_pi && !this->rt_waiter) ||
-                   (!requeue_pi && this->rt_waiter)) {
+                   (!requeue_pi && this->rt_waiter) ||
+                   this->pi_state) {
                        ret = -EINVAL;
                        break;
                }