drm/qxl: Don't take dev->struct_mutex in bo_force_delete

This change “drm/qxl: Don’t take dev->struct_mutex in bo_force_delete” in Linux kernel is authored by Daniel Vetter <daniel.vetter [at] ffwll.ch> on Thu Jul 9 23:32:46 2015 +0200.

drm/qxl: Don't take dev->struct_mutex in bo_force_delete

It really doesn't protect anything which doesn't have other locks
already. It also doesn't seem to be wired up into the driver unload
code fwiw, but that's a different issue.

Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

This Linux change may have been applied to various maintained Linux releases and you can find Linux releases including commit 2143287.

There are 4 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/gpu/drm/qxl/qxl_object.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/qxl/qxl_object.c b/drivers/gpu/drm/qxl/qxl_object.c
index 6d6f33d..b28370e 100644
--- a/drivers/gpu/drm/qxl/qxl_object.c
+++ b/drivers/gpu/drm/qxl/qxl_object.c
@@ -272,7 +272,6 @@ void qxl_bo_force_delete(struct qxl_device *qdev)
 		return;
 	dev_err(qdev->dev, "Userspace still has active objects !n");
 	list_for_each_entry_safe(bo, n, &qdev->gem.objects, list) {
-		mutex_lock(&qdev->ddev->struct_mutex);
 		dev_err(qdev->dev, "%p %p %lu %lu force freen",
 			&bo->gem_base, bo, (unsigned long)bo->gem_base.size,
 			*((unsigned long *)&bo->gem_base.refcount));
@@ -280,8 +279,7 @@ void qxl_bo_force_delete(struct qxl_device *qdev)
 		list_del_init(&bo->list);
 		mutex_unlock(&qdev->gem.mutex);
 		/* this should unref the ttm bo */
-		drm_gem_object_unreference(&bo->gem_base);
-		mutex_unlock(&qdev->ddev->struct_mutex);
+		drm_gem_object_unreference_unlocked(&bo->gem_base);
 	}
 }
 

The commit for this change in Linux stable tree is 2143287 (patch).

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