dma-buf: simplify reservation_object_get_fences_rcu a bit

We can add the exclusive fence to the list after making sure we got
a consistent state.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/322034/?series=64786&rev=1

drivers/dma-buf/reservation.c

@@ -459,13 +459,6 @@ int reservation_object_get_fences_rcu(struct reservation_object *obj,
 				if (!dma_fence_get_rcu(shared[i]))
 					break;
 			}
-
-			if (!pfence_excl && fence_excl) {
-				shared[i] = fence_excl;
-				fence_excl = NULL;
-				++i;
-				++shared_count;
-			}
 		}
 
 		if (i != shared_count || read_seqcount_retry(&obj->seq, seq)) {
@@ -480,6 +473,11 @@ unlock:
 		rcu_read_unlock();
 	} while (ret);
 
+	if (pfence_excl)
+		*pfence_excl = fence_excl;
+	else if (fence_excl)
+		shared[++shared_count] = fence_excl;
+
 	if (!shared_count) {
 		kfree(shared);
 		shared = NULL;
@@ -487,9 +485,6 @@ unlock:
 
 	*pshared_count = shared_count;
 	*pshared = shared;
-	if (pfence_excl)
-		*pfence_excl = fence_excl;
-
 	return ret;
 }
 EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu);