drm/debugfs: rework drm_debugfs_create_files implementation v2

Use managed memory allocation for this. That allows us to not keep
track of all the files any more.

v2: keep drm_debugfs_cleanup(), but rename to drm_debugfs_unregister(),
    we still need to cleanup the symlink

Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230829110115.3442-6-christian.koenig@amd.com
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>

drivers/accel/drm_accel.c

@@ -99,8 +99,6 @@ void accel_debugfs_register(struct drm_device *dev)
 {
 	struct drm_minor *minor = dev->accel;
 
-	INIT_LIST_HEAD(&minor->debugfs_list);
-	mutex_init(&minor->debugfs_lock);
 	minor->debugfs_root = dev->debugfs_root;
 
 	drm_debugfs_create_files(accel_debugfs_list, ACCEL_DEBUGFS_ENTRIES,

drivers/gpu/drm/drm_debugfs.c

@@ -234,7 +234,7 @@ EXPORT_SYMBOL(drm_debugfs_gpuva_info);
  *
  * Create a given set of debugfs files represented by an array of
  * &struct drm_info_list in the given root directory. These files will be removed
- * automatically on drm_debugfs_cleanup().
+ * automatically on drm_debugfs_dev_fini().
  */
 void drm_debugfs_create_files(const struct drm_info_list *files, int count,
 			      struct dentry *root, struct drm_minor *minor)
@@ -249,7 +249,7 @@ void drm_debugfs_create_files(const struct drm_info_list *files, int count,
 		if (features && !drm_core_check_all_features(dev, features))
 			continue;
 
-		tmp = kmalloc(sizeof(struct drm_info_node), GFP_KERNEL);
+		tmp = drmm_kzalloc(dev, sizeof(*tmp), GFP_KERNEL);
 		if (tmp == NULL)
 			continue;
 
@@ -258,14 +258,28 @@ void drm_debugfs_create_files(const struct drm_info_list *files, int count,
 						0444, root, tmp,
 						&drm_debugfs_fops);
 		tmp->info_ent = &files[i];
-
-		mutex_lock(&minor->debugfs_lock);
-		list_add(&tmp->list, &minor->debugfs_list);
-		mutex_unlock(&minor->debugfs_lock);
 	}
 }
 EXPORT_SYMBOL(drm_debugfs_create_files);
 
+int drm_debugfs_remove_files(const struct drm_info_list *files, int count,
+			     struct dentry *root, struct drm_minor *minor)
+{
+	int i;
+
+	for (i = 0; i < count; i++) {
+		struct dentry *dent = debugfs_lookup(files[i].name, root);
+
+		if (!dent)
+			continue;
+
+		drmm_kfree(minor->dev, d_inode(dent)->i_private);
+		debugfs_remove(dent);
+	}
+	return 0;
+}
+EXPORT_SYMBOL(drm_debugfs_remove_files);
+
 /**
  * drm_debugfs_dev_init - create debugfs directory for the device
  * @dev: the device which we want to create the directory for
@@ -310,8 +324,6 @@ int drm_debugfs_register(struct drm_minor *minor, int minor_id,
 	struct drm_device *dev = minor->dev;
 	char name[64];
 
-	INIT_LIST_HEAD(&minor->debugfs_list);
-	mutex_init(&minor->debugfs_lock);
 	sprintf(name, "%d", minor_id);
 	minor->debugfs_symlink = debugfs_create_symlink(name, root,
 							dev->unique);
@@ -325,48 +337,8 @@ int drm_debugfs_register(struct drm_minor *minor, int minor_id,
 	return 0;
 }
 
-int drm_debugfs_remove_files(const struct drm_info_list *files, int count,
-			     struct drm_minor *minor)
+void drm_debugfs_unregister(struct drm_minor *minor)
 {
-	struct list_head *pos, *q;
-	struct drm_info_node *tmp;
-	int i;
-
-	mutex_lock(&minor->debugfs_lock);
-	for (i = 0; i < count; i++) {
-		list_for_each_safe(pos, q, &minor->debugfs_list) {
-			tmp = list_entry(pos, struct drm_info_node, list);
-			if (tmp->info_ent == &files[i]) {
-				debugfs_remove(tmp->dent);
-				list_del(pos);
-				kfree(tmp);
-			}
-		}
-	}
-	mutex_unlock(&minor->debugfs_lock);
-	return 0;
-}
-EXPORT_SYMBOL(drm_debugfs_remove_files);
-
-static void drm_debugfs_remove_all_files(struct drm_minor *minor)
-{
-	struct drm_info_node *node, *tmp;
-
-	mutex_lock(&minor->debugfs_lock);
-	list_for_each_entry_safe(node, tmp, &minor->debugfs_list, list) {
-		debugfs_remove(node->dent);
-		list_del(&node->list);
-		kfree(node);
-	}
-	mutex_unlock(&minor->debugfs_lock);
-}
-
-void drm_debugfs_cleanup(struct drm_minor *minor)
-{
-	if (!minor->debugfs_symlink)
-		return;
-
-	drm_debugfs_remove_all_files(minor);
 	debugfs_remove(minor->debugfs_symlink);
 	minor->debugfs_symlink = NULL;
 }

drivers/gpu/drm/drm_drv.c

@@ -198,7 +198,7 @@ static int drm_minor_register(struct drm_device *dev, enum drm_minor_type type)
 	return 0;
 
 err_debugfs:
-	drm_debugfs_cleanup(minor);
+	drm_debugfs_unregister(minor);
 	return ret;
 }
 
@@ -222,7 +222,7 @@ static void drm_minor_unregister(struct drm_device *dev, enum drm_minor_type typ
 
 	device_del(minor->kdev);
 	dev_set_drvdata(minor->kdev, NULL); /* safety belt */
-	drm_debugfs_cleanup(minor);
+	drm_debugfs_unregister(minor);
 }
 
 /*

drivers/gpu/drm/drm_internal.h

@@ -184,7 +184,7 @@ void drm_debugfs_dev_fini(struct drm_device *dev);
 void drm_debugfs_dev_register(struct drm_device *dev);
 int drm_debugfs_register(struct drm_minor *minor, int minor_id,
 			 struct dentry *root);
-void drm_debugfs_cleanup(struct drm_minor *minor);
+void drm_debugfs_unregister(struct drm_minor *minor);
 void drm_debugfs_connector_add(struct drm_connector *connector);
 void drm_debugfs_connector_remove(struct drm_connector *connector);
 void drm_debugfs_crtc_add(struct drm_crtc *crtc);
@@ -205,7 +205,7 @@ static inline int drm_debugfs_register(struct drm_minor *minor, int minor_id,
 	return 0;
 }
 
-static inline void drm_debugfs_cleanup(struct drm_minor *minor)
+static inline void drm_debugfs_unregister(struct drm_minor *minor)
 {
 }
 

drivers/gpu/drm/tegra/dc.c

@@ -1746,8 +1746,15 @@ static void tegra_dc_early_unregister(struct drm_crtc *crtc)
 	unsigned int count = ARRAY_SIZE(debugfs_files);
 	struct drm_minor *minor = crtc->dev->primary;
 	struct tegra_dc *dc = to_tegra_dc(crtc);
+	struct dentry *root;
 
-	drm_debugfs_remove_files(dc->debugfs_files, count, minor);
+#ifdef CONFIG_DEBUG_FS
+	root = crtc->debugfs_entry;
+#else
+	root = NULL;
+#endif
+
+	drm_debugfs_remove_files(dc->debugfs_files, count, root, minor);
 	kfree(dc->debugfs_files);
 	dc->debugfs_files = NULL;
 }

drivers/gpu/drm/tegra/dsi.c

@@ -256,6 +256,7 @@ static void tegra_dsi_early_unregister(struct drm_connector *connector)
 	struct tegra_dsi *dsi = to_dsi(output);
 
 	drm_debugfs_remove_files(dsi->debugfs_files, count,
+				 connector->debugfs_entry,
 				 connector->dev->primary);
 	kfree(dsi->debugfs_files);
 	dsi->debugfs_files = NULL;

drivers/gpu/drm/tegra/hdmi.c

@@ -1116,7 +1116,8 @@ static void tegra_hdmi_early_unregister(struct drm_connector *connector)
 	unsigned int count = ARRAY_SIZE(debugfs_files);
 	struct tegra_hdmi *hdmi = to_hdmi(output);
 
-	drm_debugfs_remove_files(hdmi->debugfs_files, count, minor);
+	drm_debugfs_remove_files(hdmi->debugfs_files, count,
+				 connector->debugfs_entry, minor);
 	kfree(hdmi->debugfs_files);
 	hdmi->debugfs_files = NULL;
 }

drivers/gpu/drm/tegra/sor.c

@@ -1708,6 +1708,7 @@ static void tegra_sor_early_unregister(struct drm_connector *connector)
 	struct tegra_sor *sor = to_sor(output);
 
 	drm_debugfs_remove_files(sor->debugfs_files, count,
+				 connector->debugfs_entry,
 				 connector->dev->primary);
 	kfree(sor->debugfs_files);
 	sor->debugfs_files = NULL;

include/drm/drm_debugfs.h

@@ -142,8 +142,8 @@ struct drm_debugfs_entry {
 void drm_debugfs_create_files(const struct drm_info_list *files,
 			      int count, struct dentry *root,
 			      struct drm_minor *minor);
-int drm_debugfs_remove_files(const struct drm_info_list *files,
-			     int count, struct drm_minor *minor);
+int drm_debugfs_remove_files(const struct drm_info_list *files, int count,
+			     struct dentry *root, struct drm_minor *minor);
 
 void drm_debugfs_add_file(struct drm_device *dev, const char *name,
 			  int (*show)(struct seq_file*, void*), void *data);

include/drm/drm_file.h

@@ -81,9 +81,6 @@ struct drm_minor {
 
 	struct dentry *debugfs_symlink;
 	struct dentry *debugfs_root;
-
-	struct list_head debugfs_list;
-	struct mutex debugfs_lock; /* Protects debugfs_list. */
 };
 
 /**