[PATCH] drm/ttm: Don't clear page metadata of imported sg pages

[Thomas Hellstrom]

These page pointers shouldn't be visible to TTM in the first place, but
until we fix that up, don't clear the page metadata because that
will upset the exporter.

Reported-by: Cristoph Haag <haagch.christoph at googleemail.com>
Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
---
 drivers/gpu/drm/ttm/ttm_tt.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index 9af9908..75f3190 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -380,6 +380,9 @@ static void ttm_tt_clear_mapping(struct ttm_tt *ttm)
 	pgoff_t i;
 	struct page **page = ttm->pages;
 
+	if (ttm->page_flags & TTM_PAGE_FLAG_SG)
+		return;
+
 	for (i = 0; i < ttm->num_pages; ++i) {
 		(*page)->mapping = NULL;
 		(*page++)->index = 0;
-- 
1.7.10.4