Commit abae9164 authored by Jeremy Cline's avatar Jeremy Cline Committed by Karol Herbst
Browse files

drm/nouveau: Add a dedicated mutex for the clients list 



Rather than protecting the nouveau_drm clients list with the lock within
the "client" nouveau_cli, add a dedicated lock to serialize access to
the list. This is both clearer and necessary to avoid lockdep being
upset with us when we need to iterate through all the clients in the
list and potentially lock their mutex, which is the same class as the
lock protecting the entire list.

Cc: stable@vger.kernel.org # 5.4+
Signed-off-by: default avatarJeremy Cline <jcline@redhat.com>
Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Reviewed-by: default avatarBen Skeggs <bskeggs@redhat.com>
Tested-by: default avatarKarol Herbst <kherbst@redhat.com>
Signed-off-by: default avatarKarol Herbst <kherbst@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201125202648.5220-3-jcline@redhat.com
Link: https://gitlab.freedesktop.org/drm/nouveau/-/merge_requests/14
parent aff2299e

drivers/gpu/drm/nouveau/nouveau_drm.c

+6 −4
Original line number Diff line number Diff line
@@ -562,6 +562,7 @@ nouveau_drm_device_init(struct drm_device *dev) 
		nvkm_dbgopt(nouveau_debug, "DRM");



	INIT_LIST_HEAD(&drm->clients);

	mutex_init(&drm->clients_lock);

	spin_lock_init(&drm->tile.lock);



	/* workaround an odd issue on nvc1 by disabling the device's
@@ -659,6 +660,7 @@ nouveau_drm_device_fini(struct drm_device *dev) 
	nouveau_cli_fini(&drm->client);

	nouveau_cli_fini(&drm->master);

	nvif_parent_dtor(&drm->parent);

	mutex_destroy(&drm->clients_lock);

	kfree(drm);

}
@@ -1090,9 +1092,9 @@ nouveau_drm_open(struct drm_device *dev, struct drm_file *fpriv) 


	fpriv->driver_priv = cli;



	mutex_lock(&drm->client.mutex);

	mutex_lock(&drm->clients_lock);

	list_add(&cli->head, &drm->clients);

	mutex_unlock(&drm->client.mutex);

	mutex_unlock(&drm->clients_lock);



done:

	if (ret && cli) {
@@ -1118,9 +1120,9 @@ nouveau_drm_postclose(struct drm_device *dev, struct drm_file *fpriv) 
		nouveau_abi16_fini(cli->abi16);

	mutex_unlock(&cli->mutex);



	mutex_lock(&drm->client.mutex);

	mutex_lock(&drm->clients_lock);

	list_del(&cli->head);

	mutex_unlock(&drm->client.mutex);

	mutex_unlock(&drm->clients_lock);



	nouveau_cli_fini(cli);

	kfree(cli);

drivers/gpu/drm/nouveau/nouveau_drv.h

+5 −0
Original line number Diff line number Diff line
@@ -139,6 +139,11 @@ struct nouveau_drm { 


	struct list_head clients;



	/**

	 * @clients_lock: Protects access to the @clients list of &struct nouveau_cli.

	 */

	struct mutex clients_lock;



	u8 old_pm_cap;



	struct {