[PATCH] drm/ttm: Fix busy codepaths of the "Fix two race conditions" commit.

[Thomas Hellstrom]

The above mentioned commit didn't queue the buffer on the delayed destroy
list under some rare circumstances. It also didn't completely honor the
remove_all parameter.

Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c |   15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index b98cb2c..db809e0 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -493,6 +493,7 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, bool remove_all)
 	int ret;
 
 	spin_lock(&bo->lock);
+retry:
 	(void) ttm_bo_wait(bo, false, false, !remove_all);
 
 	if (!bo->sync_obj) {
@@ -501,15 +502,16 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, bool remove_all)
 		spin_unlock(&bo->lock);
 
 		spin_lock(&glob->lru_lock);
-		ret = ttm_bo_reserve_locked(bo, false, true, false, 0);
+		ret = ttm_bo_reserve_locked(bo, false, !remove_all, false, 0);
 
 		/**
 		 * Someone else has the object reserved. Bail and retry.
 		 */
 
-		if (unlikely(ret != 0)) {
+		if (unlikely(ret == -EBUSY)) {
 			spin_unlock(&glob->lru_lock);
-			return 0;
+			spin_lock(&bo->lock);
+			goto requeue;
 		}
 
 		/**
@@ -524,6 +526,11 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, bool remove_all)
 			atomic_set(&bo->reserved, 0);
 			wake_up_all(&bo->event_queue);
 			spin_unlock(&glob->lru_lock);
+			spin_lock(&bo->lock);
+			if (remove_all)
+				goto retry;
+			else
+				goto requeue;
 		}
 
 		put_count = ttm_bo_del_from_lru(bo);
@@ -540,7 +547,7 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, bool remove_all)
 
 		return 0;
 	}
-
+requeue:
 	spin_lock(&glob->lru_lock);
 	if (list_empty(&bo->ddestroy)) {
 		void *sync_obj = bo->sync_obj;
-- 
1.6.2.5