Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / kernel / locking / mutex.c

diff --git a/kernel/kernel/locking/mutex.c b/kernel/kernel/locking/mutex.c
index 4cccea6..89350f9 100644 (file)
--- a/kernel/kernel/locking/mutex.c
+++ b/kernel/kernel/locking/mutex.c
@@ -277,7 +277,7 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
 static inline bool mutex_try_to_acquire(struct mutex *lock)
 {
        return !mutex_is_locked(lock) &&
-               (atomic_cmpxchg(&lock->count, 1, 0) == 1);
+               (atomic_cmpxchg_acquire(&lock->count, 1, 0) == 1);
 }
 
 /*
@@ -486,9 +486,6 @@ __ww_mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx)
        if (!hold_ctx)
                return 0;
 
-       if (unlikely(ctx == hold_ctx))
-               return -EALREADY;
-
        if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
            (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
 #ifdef CONFIG_DEBUG_MUTEXES
@@ -514,6 +511,12 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
        unsigned long flags;
        int ret;
 
+       if (use_ww_ctx) {
+               struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+               if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
+                       return -EALREADY;
+       }
+
        preempt_disable();
        mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
 
@@ -529,7 +532,8 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
         * Once more, try to acquire the lock. Only try-lock the mutex if
         * it is unlocked to reduce unnecessary xchg() operations.
         */
-       if (!mutex_is_locked(lock) && (atomic_xchg(&lock->count, 0) == 1))
+       if (!mutex_is_locked(lock) &&
+           (atomic_xchg_acquire(&lock->count, 0) == 1))
                goto skip_wait;
 
        debug_mutex_lock_common(lock, &waiter);
@@ -553,7 +557,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
                 * non-negative in order to avoid unnecessary xchg operations:
                 */
                if (atomic_read(&lock->count) >= 0 &&
-                   (atomic_xchg(&lock->count, -1) == 1))
+                   (atomic_xchg_acquire(&lock->count, -1) == 1))
                        break;
 
                /*
@@ -867,7 +871,7 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
 
        spin_lock_mutex(&lock->wait_lock, flags);
 
-       prev = atomic_xchg(&lock->count, -1);
+       prev = atomic_xchg_acquire(&lock->count, -1);
        if (likely(prev == 1)) {
                mutex_set_owner(lock);
                mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);