[PATCH v4 2/4] drm: add debugfs support on per client-id basis

[Sunil Khatri]

add support to add a directory for each client-id
with root at the dri level. Since the clients are
unique and not just related to one single drm device,
so it makes more sense to add all the client based
nodes with root as dri.

Also create a symlink back to the parent drm device
from each client.

Signed-off-by: Sunil Khatri <sunil.khatri at amd.com>
---
 drivers/gpu/drm/drm_debugfs.c | 32 ++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_file.c    | 10 ++++++++++
 include/drm/drm_debugfs.h     | 12 ++++++++++++
 include/drm/drm_file.h        |  7 +++++++
 4 files changed, 61 insertions(+)

diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
index 5a33ec299c04..875276d5fb9f 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/drivers/gpu/drm/drm_debugfs.c
@@ -298,6 +298,38 @@ void drm_debugfs_remove_dir(void)
 	debugfs_remove(drm_debugfs_root);
 }
 
+int drm_debugfs_clients_add(struct drm_file *file)
+{
+	struct drm_device *dev;
+	char *client_dir, *symlink;
+
+	dev = file->minor->dev;
+
+	client_dir = kasprintf(GFP_KERNEL, "client-%llu", file->client_id);
+	if (!client_dir)
+		return -ENOMEM;
+
+	/* Create a debugfs directory for the client in root on drm debugfs */
+	file->debugfs_client = debugfs_create_dir(client_dir, drm_debugfs_root);
+	kfree(client_dir);
+
+	symlink = kasprintf(GFP_KERNEL, "../%s", dev->unique);
+	if (!symlink)
+		return -ENOMEM;
+
+	/* Create a link from client_id to the drm device this client id belongs to */
+	debugfs_create_symlink("device", file->debugfs_client, symlink);
+	kfree(symlink);
+
+	return 0;
+}
+
+void drm_debugfs_clients_remove(struct drm_file *file)
+{
+	debugfs_remove_recursive(file->debugfs_client);
+	file->debugfs_client = NULL;
+}
+
 /**
  * drm_debugfs_dev_init - create debugfs directory for the device
  * @dev: the device which we want to create the directory for
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 06ba6dcbf5ae..8502c5a630b1 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -39,12 +39,14 @@
 #include <linux/poll.h>
 #include <linux/slab.h>
 #include <linux/vga_switcheroo.h>
+#include <linux/debugfs.h>
 
 #include <drm/drm_client_event.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_file.h>
 #include <drm/drm_gem.h>
 #include <drm/drm_print.h>
+#include <drm/drm_debugfs.h>
 
 #include "drm_crtc_internal.h"
 #include "drm_internal.h"
@@ -143,6 +145,13 @@ struct drm_file *drm_file_alloc(struct drm_minor *minor)
 	rcu_assign_pointer(file->pid, get_pid(task_tgid(current)));
 	file->minor = minor;
 
+	ret = drm_debugfs_clients_add(file);
+	if (ret) {
+		put_pid(rcu_access_pointer(file->pid));
+		kfree(file);
+		return ERR_PTR(ret);
+	}
+
 	/* for compatibility root is always authenticated */
 	file->authenticated = capable(CAP_SYS_ADMIN);
 
@@ -236,6 +245,7 @@ void drm_file_free(struct drm_file *file)
 		     atomic_read(&dev->open_count));
 
 	drm_events_release(file);
+	drm_debugfs_clients_remove(file);
 
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 		drm_fb_release(file);
diff --git a/include/drm/drm_debugfs.h b/include/drm/drm_debugfs.h
index cf06cee4343f..4bd6cc1d0900 100644
--- a/include/drm/drm_debugfs.h
+++ b/include/drm/drm_debugfs.h
@@ -153,6 +153,9 @@ void drm_debugfs_add_files(struct drm_device *dev,
 
 int drm_debugfs_gpuva_info(struct seq_file *m,
 			   struct drm_gpuvm *gpuvm);
+
+int drm_debugfs_clients_add(struct drm_file *file);
+void drm_debugfs_clients_remove(struct drm_file *file);
 #else
 static inline void drm_debugfs_create_files(const struct drm_info_list *files,
 					    int count, struct dentry *root,
@@ -181,6 +184,15 @@ static inline int drm_debugfs_gpuva_info(struct seq_file *m,
 {
 	return 0;
 }
+
+int drm_debugfs_clients_add(struct drm_file *file)
+{
+	return 0;
+}
+
+void drm_debugfs_clients_remove(struct drm_file *file)
+{
+}
 #endif
 
 #endif /* _DRM_DEBUGFS_H_ */
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 5c3b2aa3e69d..eab7546aad79 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -400,6 +400,13 @@ struct drm_file {
 	 * @client_name_lock: Protects @client_name.
 	 */
 	struct mutex client_name_lock;
+
+	/**
+	 * @debugfs_client:
+	 *
+	 * debugfs directory for each client under a drm node.
+	 */
+	struct dentry *debugfs_client;
 };
 
 /**
-- 
2.34.1