drm: use drm_file client_name in fdinfo

Add an optional drm-client-name field to drm fdinfo's output.

Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241003124506.470931-3-pierre-eric.pelloux-prayer@amd.com
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>

Documentation/gpu/drm-usage-stats.rst

@@ -73,6 +73,11 @@ scope of each device, in which case `drm-pdev` shall be present as well.
 Userspace should make sure to not double account any usage statistics by using
 the above described criteria in order to associate data to individual clients.
 
+- drm-client-name: <valstr>
+
+String optionally set by userspace using DRM_IOCTL_SET_CLIENT_NAME.
+
+
 Utilization
 ^^^^^^^^^^^
 

drivers/gpu/drm/drm_file.c

@@ -955,6 +955,11 @@ void drm_show_fdinfo(struct seq_file *m, struct file *f)
 			   PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
 	}
 
+	mutex_lock(&file->client_name_lock);
+	if (file->client_name)
+		drm_printf(&p, "drm-client-name:\t%s\n", file->client_name);
+	mutex_unlock(&file->client_name_lock);
+
 	if (dev->driver->show_fdinfo)
 		dev->driver->show_fdinfo(&p, file);
 }