[PATCH 4/5] drm/ttm: call ttm_bo_wait while inside a reservation

[Maarten Lankhorst]

This is the last remaining function that doesn't use the reservation
lock completely to fence off access to a buffer.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 07e02c4bf5a8..a8cffb6ee1f3 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -500,17 +500,6 @@ static int ttm_bo_cleanup_refs_and_unlock(struct 
ttm_buffer_object *bo,
                if (ret)
                        return ret;

-               /*
-                * remove sync_obj with ttm_bo_wait, the wait should be
-                * finished, and no new wait object should have been added.
-                */
-               spin_lock(&bdev->fence_lock);
-               ret = ttm_bo_wait(bo, false, false, true);
-               WARN_ON(ret);
-               spin_unlock(&bdev->fence_lock);
-               if (ret)
-                       return ret;
-
                spin_lock(&glob->lru_lock);
                ret = ttm_bo_reserve_nolru(bo, false, true, false, 0);

@@ -526,8 +515,16 @@ static int ttm_bo_cleanup_refs_and_unlock(struct 
ttm_buffer_object *bo,
                        spin_unlock(&glob->lru_lock);
                        return 0;
                }
-       } else
-               spin_unlock(&bdev->fence_lock);
+
+               /*
+                * remove sync_obj with ttm_bo_wait, the wait should be
+                * finished, and no new wait object should have been added.
+                */
+               spin_lock(&bdev->fence_lock);
+               ret = ttm_bo_wait(bo, false, false, true);
+               WARN_ON(ret);
+       }
+       spin_unlock(&bdev->fence_lock);

        if (ret || unlikely(list_empty(&bo->ddestroy))) {
                ww_mutex_unlock(&bo->resv->lock);
@@ -1536,6 +1533,8 @@ int ttm_bo_wait(struct ttm_buffer_object *bo,
        void *sync_obj;
        int ret = 0;

+       lockdep_assert_held(&bo->resv->lock.base);
+
        if (likely(bo->sync_obj == NULL))
                return 0;

-- 
1.8.5.2