drm/qxl: avoid dependency lock

qxl_bo_unref calls drm_gem_object_unreference_unlocked which
locks dev->struct_mutex. However this lock could be already
locked if the call came from qxl_gem_object_free.
As we don't need to call qxl_bo_ref/qxl_bo_unref cause
qxl_release_list_add will hold a reference by itself avoid
to call them and the possible deadlock.

Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index b66ec331c17cd51f1b81022ebd29d18944258b43..4efa8e261baf59546ca24eb39920bc4159358ab7 100644 (file)
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -307,7 +307,7 @@ int qxl_alloc_surface_release_reserved(struct qxl_device *qdev,
                idr_ret = qxl_release_alloc(qdev, QXL_RELEASE_SURFACE_CMD, release);
                if (idr_ret < 0)
                        return idr_ret;
-               bo = qxl_bo_ref(to_qxl_bo(entry->tv.bo));
+               bo = to_qxl_bo(entry->tv.bo);
 
                (*release)->release_offset = create_rel->release_offset + 64;
 
@@ -316,8 +316,6 @@ int qxl_alloc_surface_release_reserved(struct qxl_device *qdev,
                info = qxl_release_map(qdev, *release);
                info->id = idr_ret;
                qxl_release_unmap(qdev, *release, info);
-
-               qxl_bo_unref(&bo);
                return 0;
        }