This is a note to let you know that I've just added the patch titled
drm/nouveau: Add a dedicated mutex for the clients list
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-nouveau-add-a-dedicated-mutex-for-the-clients-list.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From abae9164a421bc4a41a3769f01ebcd1f9d955e0e Mon Sep 17 00:00:00 2001
From: Jeremy Cline <jcline@xxxxxxxxxx>
Date: Wed, 25 Nov 2020 15:26:47 -0500
Subject: drm/nouveau: Add a dedicated mutex for the clients list
From: Jeremy Cline <jcline@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx # 5.4+
Signed-off-by: Jeremy Cline <jcline@xxxxxxxxxx>
Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
Reviewed-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
Tested-by: Karol Herbst <kherbst@xxxxxxxxxx>
Signed-off-by: Karol Herbst <kherbst@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20201125202648.5220-3-jcline@xxxxxxxxxx
Link: https://gitlab.freedesktop.org/drm/nouveau/-/merge_requests/14
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/nouveau/nouveau_drm.c | 10 ++++++----
drivers/gpu/drm/nouveau/nouveau_drv.h | 5 +++++
2 files changed, 11 insertions(+), 4 deletions(-)
--- 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_devic
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_devic
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,
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
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);
--- 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 {
Patches currently in stable-queue which might be from jcline@xxxxxxxxxx are
queue-5.10/drm-nouveau-add-a-dedicated-mutex-for-the-clients-list.patch
queue-5.10/drm-nouveau-clean-up-all-clients-on-device-removal.patch
queue-5.10/drm-nouveau-use-drm_dev_unplug-during-device-removal.patch
