From 9221aff33edb627ea52a51379862f46e63e7c0c9 Mon Sep 17 00:00:00 2001 From: Jeremy Cline Date: Wed, 25 Nov 2020 15:26:47 -0500 Subject: [PATCH] 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 --- drivers/gpu/drm/nouveau/nouveau_drm.c | 10 ++++++---- drivers/gpu/drm/nouveau/nouveau_drv.h | 5 +++++ 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c index 42fc5c8..89f72b91 100644 --- a/drivers/gpu/drm/nouveau/nouveau_drm.c +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c @@ -557,6 +557,7 @@ 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 @@ -654,6 +655,7 @@ 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); } @@ -1086,9 +1088,9 @@ 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) { @@ -1114,9 +1116,9 @@ 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 b802550..8b252dc 100644 --- a/drivers/gpu/drm/nouveau/nouveau_drv.h +++ b/drivers/gpu/drm/nouveau/nouveau_drv.h @@ -142,6 +142,11 @@ 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 { -- 2.7.4