[PATCH 3.13.y-ckt 026/108] drm/ttm: Fixed a read/write lock imbalance

From: Kamal Mostafa
Date: Fri Jan 22 2016 - 18:55:41 EST


3.13.11-ckt33 -stable review patch. If anyone has any objections, please let me know.

---8<------------------------------------------------------------

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: Kamal Mostafa <kamal@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 3daa9a3..9b7cb11 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)
spin_unlock(&lock->lock);
}
} else
- wait_event(lock->queue, __ttm_read_lock(lock));
+ wait_event(lock->queue, __ttm_write_lock(lock));

return ret;
}
--
1.9.1