[PATCH -fixes] drm/ttm: Fix spinlock imbalance

[Thomas Hellstrom]

This imbalance may cause hangs when TTM is trying to swap out a buffer
that is already on the delayed delete list.

Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob at vmware.com>
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/ttm/ttm_bo.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 36792bd..b67cfca 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1834,6 +1834,7 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink)
 			spin_unlock(&glob->lru_lock);
 			(void) ttm_bo_cleanup_refs(bo, false, false, false);
 			kref_put(&bo->list_kref, ttm_bo_release_list);
+			spin_lock(&glob->lru_lock);
 			continue;
 		}
 
-- 
1.7.4.4