[PATCH 4.9 16/24] drm/vmwgfx: Return error code from vmw_execbuf_copy_fence_user

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

------------------

From: Thomas Hellstrom <thellstrom@vmware.com>

commit 728354c005c36eaf44b6e5552372b67e60d17f56 upstream.

The function was unconditionally returning 0, and a caller would have to
rely on the returned fence pointer being NULL to detect errors. However,
the function vmw_execbuf_copy_fence_user() would expect a non-zero error
code in that case and would BUG otherwise.

So make sure we return a proper non-zero error code if the fence pointer
returned is NULL.

Cc: <stable@vger.kernel.org>
Fixes: ae2a104058e2: ("vmwgfx: Implement fence objects")
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Deepak Rawat <drawat@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -3769,7 +3769,7 @@ int vmw_execbuf_fence_commands(struct dr
 		*p_fence = NULL;
 	}
 
-	return 0;
+	return ret;
 }
 
 /**