drm/ttm: fix the tt_populated check in ttm_tt_destroy()
authorBen Skeggs <bskeggs@redhat.com>
Tue, 17 Sep 2013 04:21:15 +0000 (14:21 +1000)
committerDave Airlie <airlied@redhat.com>
Thu, 19 Sep 2013 01:48:30 +0000 (11:48 +1000)
commit182b17c8dc4e83aab000ce86587b6810e515da87
tree64962eec5002e424d812cd9564e549daf801c03a
parent4f7d1bc973ec71dfeeb951765cafe1ff3a63243e
drm/ttm: fix the tt_populated check in ttm_tt_destroy()

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>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Cc: stable@vger.kernel.org
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drivers/gpu/drm/ttm/ttm_tt.c