[PATCH 2/2] drm/ttm: fix ttm_bo_cleanup_refs_or_queue once more

[Christian König]

From: Christian König <christian.koenig at amd.com>

With shared reservation objects __ttm_bo_reserve() can easily fail even on
destroyed BOs. This prevents correct handling when we need to individualize
the reservation object.

Fix this by individualizing the object before even trying to reserve it.

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 180ce62..bee77d3 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -440,28 +440,29 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
 	struct ttm_bo_global *glob = bo->glob;
 	int ret;
 
+	ret = ttm_bo_individualize_resv(bo);
+	if (ret) {
+		/* Last resort, if we fail to allocate memory for the
+		 * fences block for the BO to become idle
+		 */
+		reservation_object_wait_timeout_rcu(bo->resv, true, false,
+						    30 * HZ);
+		spin_lock(&glob->lru_lock);
+		goto error;
+	}
+
 	spin_lock(&glob->lru_lock);
 	ret = __ttm_bo_reserve(bo, false, true, NULL);
-
 	if (!ret) {
-		if (!ttm_bo_wait(bo, false, true)) {
+		if (reservation_object_test_signaled_rcu(&bo->ttm_resv, true)) {
 			ttm_bo_del_from_lru(bo);
 			spin_unlock(&glob->lru_lock);
+			if (bo->resv != &bo->ttm_resv)
+				reservation_object_unlock(&bo->ttm_resv);
 			ttm_bo_cleanup_memtype_use(bo);
-
 			return;
 		}
 
-		ret = ttm_bo_individualize_resv(bo);
-		if (ret) {
-			/* Last resort, if we fail to allocate memory for the
-			 * fences block for the BO to become idle and free it.
-			 */
-			spin_unlock(&glob->lru_lock);
-			ttm_bo_wait(bo, true, true);
-			ttm_bo_cleanup_memtype_use(bo);
-			return;
-		}
 		ttm_bo_flush_all_fences(bo);
 
 		/*
@@ -474,11 +475,12 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
 			ttm_bo_add_to_lru(bo);
 		}
 
-		if (bo->resv != &bo->ttm_resv)
-			reservation_object_unlock(&bo->ttm_resv);
 		__ttm_bo_unreserve(bo);
 	}
+	if (bo->resv != &bo->ttm_resv)
+		reservation_object_unlock(&bo->ttm_resv);
 
+error:
 	kref_get(&bo->list_kref);
 	list_add_tail(&bo->ddestroy, &bdev->ddestroy);
 	spin_unlock(&glob->lru_lock);
-- 
2.7.4