1 files changed, 20 insertions, 10 deletions

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index 38b4110378de..bea3e9858aca 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -186,6 +186,13 @@ int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences)
 
 	dma_resv_assert_held(obj);
 
+	/* Driver and component code should never call this function with
+	 * num_fences=0. If they do it usually points to bugs when calculating
+	 * the number of needed fences dynamically.
+	 */
+	if (WARN_ON(!num_fences))
+		return -EINVAL;
+
 	old = dma_resv_fences_list(obj);
 	if (old && old->max_fences) {
 		if ((old->num_fences + num_fences) <= old->max_fences)
@@ -301,7 +308,7 @@ void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence,
 
 		dma_resv_list_entry(fobj, i, obj, &old, &old_usage);
 		if ((old->context == fence->context && old_usage >= usage &&
-		     dma_fence_is_later(fence, old)) ||
+		     dma_fence_is_later_or_same(fence, old)) ||
 		    dma_fence_is_signaled(old)) {
 			dma_resv_list_set(fobj, i, fence, usage);
 			dma_fence_put(old);
@@ -313,8 +320,9 @@ void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence,
 	count++;
 
 	dma_resv_list_set(fobj, i, fence, usage);
-	/* pointer update must be visible before we extend the num_fences */
-	smp_store_mb(fobj->num_fences, count);
+	/* fence update must be visible before we extend the num_fences */
+	smp_wmb();
+	fobj->num_fences = count;
 }
 EXPORT_SYMBOL(dma_resv_add_fence);
 
@@ -405,7 +413,7 @@ static void dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor)
  *
  * Beware that the iterator can be restarted.  Code which accumulates statistics
  * or similar needs to check for this with dma_resv_iter_is_restarted(). For
- * this reason prefer the locked dma_resv_iter_first() whenver possible.
+ * this reason prefer the locked dma_resv_iter_first() whenever possible.
  *
  * Returns the first fence from an unlocked dma_resv obj.
  */
@@ -428,7 +436,7 @@ EXPORT_SYMBOL(dma_resv_iter_first_unlocked);
  *
  * Beware that the iterator can be restarted.  Code which accumulates statistics
  * or similar needs to check for this with dma_resv_iter_is_restarted(). For
- * this reason prefer the locked dma_resv_iter_next() whenver possible.
+ * this reason prefer the locked dma_resv_iter_next() whenever possible.
  *
  * Returns the next fence from an unlocked dma_resv obj.
  */
@@ -677,11 +685,13 @@ long dma_resv_wait_timeout(struct dma_resv *obj, enum dma_resv_usage usage,
 	dma_resv_iter_begin(&cursor, obj, usage);
 	dma_resv_for_each_fence_unlocked(&cursor, fence) {
 
-		ret = dma_fence_wait_timeout(fence, intr, ret);
-		if (ret <= 0) {
-			dma_resv_iter_end(&cursor);
-			return ret;
-		}
+		ret = dma_fence_wait_timeout(fence, intr, timeout);
+		if (ret <= 0)
+			break;
+
+		/* Even for zero timeout the return value is 1 */
+		if (timeout)
+			timeout = ret;
 	}
 	dma_resv_iter_end(&cursor);