[PATCH] drm: fix drm_mode_getconnector() locking imbalance regression

[Tommi Rantala]

Regression in commit 2caa80e72b57c6216aec6f6a11fcfb4fec46daa0
Author: Daniel Vetter <daniel.vetter at ffwll.ch>
Date:   Sun Feb 22 11:38:36 2015 +0100

    drm: Fix deadlock due to getconnector locking changes

If the drm_connector_find() call returns NULL, we should no longer
call drm_modeset_unlock() to avoid locking imbalance.

Signed-off-by: Tommi Rantala <tt.rantala at gmail.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/drm_crtc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 679b10e..b6f076b 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -2121,7 +2121,7 @@ int drm_mode_getconnector(struct drm_device *dev, void 
*data,
        connector = drm_connector_find(dev, out_resp->connector_id);
        if (!connector) {
                ret = -ENOENT;
-               goto out;
+               goto out_unlock;
        }

        for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++)
@@ -2201,6 +2201,8 @@ int drm_mode_getconnector(struct drm_device *dev, void 
*data,

 out:
        drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
+out_unlock:
        mutex_unlock(&dev->mode_config.mutex);

        return ret;
-- 
2.1.0