From: Jeremy Cline Date: Wed, 25 Nov 2020 20:26:47 +0000 (-0500) Subject: drm/nouveau: Add a dedicated mutex for the clients list X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=4ee6807a1ad756ca151eaa4ac57c96ffbbac926f;p=linux.git drm/nouveau: Add a dedicated mutex for the clients list commit abae9164a421bc4a41a3769f01ebcd1f9d955e0e upstream. 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: Jeremy Cline Reviewed-by: Lyude Paul Reviewed-by: Ben Skeggs Tested-by: Karol Herbst Signed-off-by: Karol Herbst Link: https://patchwork.freedesktop.org/patch/msgid/20201125202648.5220-3-jcline@redhat.com Link: https://gitlab.freedesktop.org/drm/nouveau/-/merge_requests/14 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c index 6109cd9e33991..a420320439f26 100644 --- a/drivers/gpu/drm/nouveau/nouveau_drm.c +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c @@ -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); diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h index ba65f136cf481..b2a970aa9bf4b 100644 --- a/drivers/gpu/drm/nouveau/nouveau_drv.h +++ b/drivers/gpu/drm/nouveau/nouveau_drv.h @@ -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 {