[PATCH 3.16.y-ckt 009/128] drm/ttm: Fixed a read/write lock imbalance

From: Luis Henriques
Date: Sun Jan 24 2016 - 17:03:11 EST

3.16.7-ckt23 -stable review patch. If anyone has any objections, please let me know.


From: Thomas Hellstrom <thellstrom@xxxxxxxxxx>

commit 025af189fb44250206dd8a32fa4a682392af3301 upstream.

In ttm_write_lock(), the uninterruptible path should call
__ttm_write_lock() not __ttm_read_lock(). This fixes a vmwgfx hang
on F23 start up.

syeh: Extracted this from one of Thomas' internal patches.

Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Reviewed-by: Sinclair Yeh <syeh@xxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
drivers/gpu/drm/ttm/ttm_lock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ttm/ttm_lock.c b/drivers/gpu/drm/ttm/ttm_lock.c
index 6a954544727f..f154fb1929bd 100644
--- a/drivers/gpu/drm/ttm/ttm_lock.c
+++ b/drivers/gpu/drm/ttm/ttm_lock.c
@@ -180,7 +180,7 @@ int ttm_write_lock(struct ttm_lock *lock, bool interruptible)
} else
- wait_event(lock->queue, __ttm_read_lock(lock));
+ wait_event(lock->queue, __ttm_write_lock(lock));

return ret;