dma-buf: fix reservation_object_wait_timeout_rcu once more v2

We need to set shared_count even if we already have a fence to wait for.

v2: init i to -1 as well
Signed-off-by: Christian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
Tested-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180122200003.6665-1-christian.koenig@amd.com

drivers/dma-buf/reservation.c

@@ -471,13 +471,15 @@ long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
 					 unsigned long timeout)
 {
 	struct dma_fence *fence;
-	unsigned seq, shared_count, i = 0;
+	unsigned seq, shared_count;
 	long ret = timeout ? timeout : 1;
+	int i;
 
 retry:
 	shared_count = 0;
 	seq = read_seqcount_begin(&obj->seq);
 	rcu_read_lock();
+	i = -1;
 
 	fence = rcu_dereference(obj->fence_excl);
 	if (fence && !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
@@ -493,14 +495,14 @@ long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
 		fence = NULL;
 	}
 
-	if (!fence && wait_all) {
+	if (wait_all) {
 		struct reservation_object_list *fobj =
 						rcu_dereference(obj->fence);
 
 		if (fobj)
 			shared_count = fobj->shared_count;
 
-		for (i = 0; i < shared_count; ++i) {
+		for (i = 0; !fence && i < shared_count; ++i) {
 			struct dma_fence *lfence = rcu_dereference(fobj->shared[i]);
 
 			if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,