On Tue, May 19, 2020 at 03:52:10PM +0000, Luis Chamberlain wrote:

On Tue, May 19, 2020 at 04:44:08PM +0200, Greg KH wrote:

quoted

On Sat, May 16, 2020 at 03:19:54AM +0000, Luis Chamberlain wrote:

quoted

 struct dentry *blk_debugfs_root;
+struct dentry *blk_debugfs_bsg = NULL;

checkpatch didn't complain about "= NULL;"?

Will remove.

quoted

quoted

+static void queue_debugfs_register_type(struct request_queue *q,
+					const char *name,
+					enum blk_debugfs_dir_type type)
+{
+	struct dentry *base_dir = queue_get_base_dir(type);

And it could be a simple if statement instead.

Oh well, I don't have to maintain this :)

I'll just use that, but yeah I think its a matter of preference.

quoted

quoted

+/**
+ * blk_queue_debugfs_register - register the debugfs_dir for the block device
+ * @q: the associated request_queue of the block device
+ * @name: the name of the block device exposed
+ *
+ * This is used to create the debugfs_dir used by the block layer and blktrace.
+ * Drivers which use any of the *add_disk*() calls or variants have this called
+ * automatically for them. This directory is removed automatically on
+ * blk_release_queue() once the request_queue reference count reaches 0.
+ */
+void blk_queue_debugfs_register(struct request_queue *q, const char *name)
+{
+	queue_debugfs_register_type(q, name, BLK_DBG_DIR_BASE);
+}
+EXPORT_SYMBOL_GPL(blk_queue_debugfs_register);
+
+/**
+ * blk_queue_debugfs_unregister - remove the debugfs_dir for the block device
+ * @q: the associated request_queue of the block device
+ *
+ * Removes the debugfs_dir for the request_queue on the associated block device.
+ * This is handled for you on blk_release_queue(), and that should only be
+ * called once.
+ *
+ * Since we don't care where the debugfs_dir was created this is used for all
+ * types of of enum blk_debugfs_dir_type.
+ */
+void blk_queue_debugfs_unregister(struct request_queue *q)
+{
+	debugfs_remove_recursive(q->debugfs_dir);
+}

Why is register needed to be exported, but unregister does not?  Does
some driver not properly clean things up?

Is the comment on blk_queue_debugfs_register() not sufficient?

Ah, hm, ok, I guess so.

I thought I was going overboard with how clear this was.  Should I also
add a note here on unregister?

Not really, it's fine, thanks.

greg k-h