On 09/17/2013 06:21 AM, Ben Skeggs wrote:

From: Ben Skeggs bskeggs@redhat.com

After a vmalloc failure in ttm_dma_tt_alloc_page_directory(), ttm_dma_tt_init() will call ttm_tt_destroy() to cleanup, and end up inside the driver's unpopulate() hook when populate() has never yet been called.

On nouveau, the first issue to be hit because of this is that dma_address[] may be a NULL pointer. After working around this, ttm_pool_unpopulate() may potentially hit the same issue with the pages[] array.

It seems to make more sense to avoid calling unpopulate on already unpopulated TTMs than to add checks to all the implementations.

Signed-off-by: Ben Skeggs bskeggs@redhat.com Cc: Jerome Glisse jglisse@redhat.com Cc: Thomas Hellstrom thellstrom@vmware.com

---

drivers/gpu/drm/ttm/ttm_tt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c index 5e93a52..210d503 100644 --- a/drivers/gpu/drm/ttm/ttm_tt.c +++ b/drivers/gpu/drm/ttm/ttm_tt.c @@ -170,7 +170,7 @@ void ttm_tt_destroy(struct ttm_tt *ttm) ttm_tt_unbind(ttm); }

• if (likely(ttm->pages != NULL)) {

• if (ttm->state == tt_unbound) { ttm->bdev->driver->ttm_tt_unpopulate(ttm); }

Looks good to me.

Reviewed-by: Thomas Hellstrom thellstrom@vmware.com