On 17/01/2023 16:03, Stanislaw Gruszka wrote:
Hi
On Thu, Jan 12, 2023 at 04:56:01PM +0000, Tvrtko Ursulin wrote:
From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
To enable propagation of settings from the cgroup drm controller to drm we
need to start tracking which processes own which drm clients.
Implement that by tracking the struct pid pointer of the owning process in
a new XArray, pointing to a structure containing a list of associated
struct drm_file pointers.
Clients are added and removed under the filelist mutex and RCU list
operations are used below it to allow for lockless lookup.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
<snip>
+int drm_clients_open(struct drm_file *file_priv)
+{
+ struct drm_device *dev = file_priv->minor->dev;
+ struct drm_pid_clients *clients;
+ bool new_client = false;
+ unsigned long pid;
+
+ lockdep_assert_held(&dev->filelist_mutex);
+
+ pid = (unsigned long)rcu_access_pointer(file_priv->pid);
+ clients = xa_load(&drm_pid_clients, pid);
+ if (!clients) {
+ clients = __alloc_clients();
+ if (!clients)
+ return -ENOMEM;
+ new_client = true;
+ }
+ atomic_inc(&clients->num);
+ list_add_tail_rcu(&file_priv->clink, &clients->file_list);
+ if (new_client) {
+ void *xret;
+
+ xret = xa_store(&drm_pid_clients, pid, clients, GFP_KERNEL);
+ if (xa_err(xret)) {
+ list_del_init(&file_priv->clink);
+ kfree(clients);
+ return PTR_ERR(clients);
This looks incorrect, rather xa_err(xret) should be returned.
Thanks, looks like a copy & paste error. Noted to correct before next
public post.
Regards,
Tvrtko
