diff options
Diffstat (limited to 'include/drm/drm_file.h')
| -rw-r--r-- | include/drm/drm_file.h | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h index b81b3bfb08c8..a3acb7ac3550 100644 --- a/include/drm/drm_file.h +++ b/include/drm/drm_file.h @@ -226,15 +226,31 @@ struct drm_file { /** * @master: * - * Master this node is currently associated with. Only relevant if - * drm_is_primary_client() returns true. Note that this only - * matches &drm_device.master if the master is the currently active one. + * Master this node is currently associated with. Protected by struct + * &drm_device.master_mutex, and serialized by @master_lookup_lock. + * + * Only relevant if drm_is_primary_client() returns true. Note that + * this only matches &drm_device.master if the master is the currently + * active one. + * + * To update @master, both &drm_device.master_mutex and + * @master_lookup_lock need to be held, therefore holding either of + * them is safe and enough for the read side. + * + * When dereferencing this pointer, either hold struct + * &drm_device.master_mutex for the duration of the pointer's use, or + * use drm_file_get_master() if struct &drm_device.master_mutex is not + * currently held and there is no other need to hold it. This prevents + * @master from being freed during use. * * See also @authentication and @is_master and the :ref:`section on * primary nodes and authentication <drm_primary_node>`. */ struct drm_master *master; + /** @master_lock: Serializes @master. */ + spinlock_t master_lookup_lock; + /** @pid: Process that opened this file. */ struct pid *pid; |