1 files changed, 12 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 66ee9d888d16..6ff5d655c202 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -434,20 +434,28 @@ i915_gem_object_wait_reservation(struct reservation_object *resv,
                         dma_fence_put(shared[i]);
                 kfree(shared);
 
+                /*
+                 * If both shared fences and an exclusive fence exist,
+                 * then by construction the shared fences must be later
+                 * than the exclusive fence. If we successfully wait for
+                 * all the shared fences, we know that the exclusive fence
+                 * must all be signaled. If all the shared fences are
+                 * signaled, we can prune the array and recover the
+                 * floating references on the fences/requests.
+                 */
                 prune_fences = count && timeout >= 0;
         } else {
                 excl = reservation_object_get_excl_rcu(resv);
         }
 
-        if (excl && timeout >= 0) {
+        if (excl && timeout >= 0)
                 timeout = i915_gem_object_wait_fence(excl, flags, timeout,
                                                      rps_client);
-                prune_fences = timeout >= 0;
-        }
 
         dma_fence_put(excl);
 
-        /* Oportunistically prune the fences iff we know they have *all* been
+        /*
+         * Opportunistically prune the fences iff we know they have *all* been
          * signaled and that the reservation object has not been changed (i.e.
          * no new fences have been added).
          */