[PATCH v6 08/11] devm-helpers: Add resource managed version of debugfs directory create function

["Marek Behún" <kabel@kernel.org>]

A few drivers register a devm action to remove a debugfs directory,
implementing a one-liner function that calls debufs_remove_recursive().
Help drivers avoid this repeated implementations by adding managed
version of debugfs directory create function.

Signed-off-by: Marek Behún <kabel@kernel.org>
---
 include/linux/devm-helpers.h | 40 ++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/include/linux/devm-helpers.h b/include/linux/devm-helpers.h
index fe62b28baf03..58e0a7fbd549 100644
--- a/include/linux/devm-helpers.h
+++ b/include/linux/devm-helpers.h
@@ -23,6 +23,7 @@
  * already ran.
  */
 
+#include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/kconfig.h>
 #include <linux/irqdomain.h>
@@ -130,4 +131,43 @@ static inline int devm_irq_create_mapping(struct device *dev,
 	return virq;
 }
 
+static inline void devm_debugfs_dir_recursive_drop(void *res)
+{
+	debugfs_remove_recursive(res);
+}
+
+/**
+ * devm_debugfs_create_dir - Resource managed debugfs directory creation
+ * @dev:	Device which lifetime the directory is bound to
+ * @name:	a pointer to a string containing the name of the directory to
+ *		create
+ * @parent:	a pointer to the parent dentry for this file.  This should be a
+ *		directory dentry if set.  If this parameter is NULL, then the
+ *		directory will be created in the root of the debugfs filesystem.
+ *
+ * Create a debugfs directory which is automatically recursively removed when
+ * the driver is detached. A few drivers create debugfs directories which they
+ * want removed before driver is detached.
+ * devm_debugfs_create_dir() can be used to omit the explicit
+ * debugfs_remove_recursive() call when driver is detached.
+ */
+static inline struct dentry *
+devm_debugfs_create_dir(struct device *dev, const char *name,
+			struct dentry *parent)
+{
+	struct dentry *dentry;
+	int err;
+
+	dentry = debugfs_create_dir(name, parent);
+	if (IS_ERR(dentry))
+		return dentry;
+
+	err = devm_add_action_or_reset(dev, devm_debugfs_dir_recursive_drop,
+				       dentry);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	return dentry;
+}
+
 #endif
-- 
2.43.2