drm/ttm: cope with reserved buffers on swap list in ttm_bo_swapout, v2

[firefly-linux-kernel-4.4.55.git] / drivers / gpu / drm / ttm / ttm_bo.c

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index ef223d581a705062a24958966e5530da5f32628c..9a479885bf5902a983400d56f3cf6b079a1c41ff 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1813,41 +1813,25 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink)
        uint32_t swap_placement = (TTM_PL_FLAG_CACHED | TTM_PL_FLAG_SYSTEM);
 
        spin_lock(&glob->lru_lock);
-       while (ret == -EBUSY) {
-               if (unlikely(list_empty(&glob->swap_lru))) {
-                       spin_unlock(&glob->lru_lock);
-                       return -EBUSY;
-               }
-
-               bo = list_first_entry(&glob->swap_lru,
-                                     struct ttm_buffer_object, swap);
-               kref_get(&bo->list_kref);
-
-               if (!list_empty(&bo->ddestroy)) {
-                       ttm_bo_reserve_locked(bo, false, false, false, 0);
-                       ttm_bo_cleanup_refs_and_unlock(bo, false, false);
+       list_for_each_entry(bo, &glob->swap_lru, swap) {
+               ret = ttm_bo_reserve_locked(bo, false, true, false, 0);
+               if (!ret)
+                       break;
+       }
 
-                       kref_put(&bo->list_kref, ttm_bo_release_list);
-                       spin_lock(&glob->lru_lock);
-                       continue;
-               }
+       if (ret) {
+               spin_unlock(&glob->lru_lock);
+               return ret;
+       }
 
-               /**
-                * Reserve buffer. Since we unlock while sleeping, we need
-                * to re-check that nobody removed us from the swap-list while
-                * we slept.
-                */
+       kref_get(&bo->list_kref);
 
-               ret = ttm_bo_reserve_locked(bo, false, true, false, 0);
-               if (unlikely(ret == -EBUSY)) {
-                       spin_unlock(&glob->lru_lock);
-                       ttm_bo_wait_unreserved(bo, false);
-                       kref_put(&bo->list_kref, ttm_bo_release_list);
-                       spin_lock(&glob->lru_lock);
-               }
+       if (!list_empty(&bo->ddestroy)) {
+               ret = ttm_bo_cleanup_refs_and_unlock(bo, false, false);
+               kref_put(&bo->list_kref, ttm_bo_release_list);
+               return ret;
        }
 
-       BUG_ON(ret != 0);
        put_count = ttm_bo_del_from_lru(bo);
        spin_unlock(&glob->lru_lock);