[PATCH 3.10 170/268] drm/ttm: Make sure BOs being swapped out are cacheable

Willy Tarreau
2017-06-19T18:34:53Z

From: Michel Dänzer <michel.daenzer@amd.com>

commit 239ac65fa5ffab71adf66e642750f940e7241d99 upstream.

The current caching state may not be tt_cached, even though the
placement contains TTM_PL_FLAG_CACHED, because placement can contain
multiple caching flags. Trying to swap out such a BO would trip up the

BUG_ON(ttm->caching_state != tt_cached);

in ttm_tt_swapout.

Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Christian König <christian.koenig@amd.com>.
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
drivers/gpu/drm/ttm/ttm_bo.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 0ac0a88..f1672f3 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1866,7 +1866,6 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink)
struct ttm_buffer_object *bo;
int ret = -EBUSY;
int put_count;
- uint32_t swap_placement = (TTM_PL_FLAG_CACHED | TTM_PL_FLAG_SYSTEM);

spin_lock(&glob->lru_lock);
list_for_each_entry(bo, &glob->swap_lru, swap) {
@@ -1904,7 +1903,8 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink)
if (unlikely(ret != 0))
goto out;

- if ((bo->mem.placement & swap_placement) != swap_placement) {
+ if (bo->mem.mem_type != TTM_PL_SYSTEM ||
+ bo->ttm->caching_state != tt_cached) {
struct ttm_mem_reg evict_mem;

evict_mem = bo->mem;
--
2.8.0.rc2.1.gbe9624a