[Intel-gfx] [PATCH] drm: Release filp before global lock

[Chris Wilson]

The file is not part of the global drm resource and can be released
prior to take the global mutex to drop the open_count (and potentially
close) the drm device.

However, inside drm_close_helper() there are a number of dev->driver
callbacks that take the drm_device as the first parameter... Worryingly
some of those callbacks may be (implicitly) depending on the global
mutex.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/drm_file.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 92d16724f949..84ed313ee2e9 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -438,12 +438,12 @@ int drm_release(struct inode *inode, struct file *filp)
 	struct drm_minor *minor = file_priv->minor;
 	struct drm_device *dev = minor->dev;
 
-	mutex_lock(&drm_global_mutex);
-
 	DRM_DEBUG("open_count = %d\n", dev->open_count);
 
 	drm_close_helper(filp);
 
+	mutex_lock(&drm_global_mutex);
+
 	if (!--dev->open_count)
 		drm_lastclose(dev);
 
-- 
2.25.0