On Wed, Apr 29, 2020 at 11:45:42AM +0000, Luis Chamberlain wrote:

On Wed, Apr 29, 2020 at 04:26:37AM -0700, Christoph Hellwig wrote:

quoted

I can't say I'm a fan of all these long backtraces in commit logs..

quoted

+static struct dentry *blk_debugfs_dir_register(const char *name)
+{
+	return debugfs_create_dir(name, blk_debugfs_root);
+}

I don't think we really need this helper.

We don't export blk_debugfs_root, didn't think we'd want to, and
since only a few scew funky drivers would use the struct gendisk
and also support BLKTRACE, I didn't think we'd want to export it
now.

A new block private symbol namespace alright?

Err, that function is static and has two callers.

quoted

This could be simplified down to:

	if (bdev && bdev != bdev->bd_contains)
		return bdev->bd_part->debugfs_dir;
	return q->debugfs_dir;

Given that bd_part is in __blkdev_get very near bd_contains.

Ah neat.

quoted

Also given that this patch completely rewrites blk_trace_debugfs_dir is
there any point in the previous patch?

Still think it helps with making this patch easier to read, but I don't
care, lemme know if I should just fold it.

In fact I'm not even sure we need the helper.  Modulo the comment
this just becomes a:

	if (bdev && bdev != bdev->bd_contains)
 		dir = bdev->bd_part->debugfs_dir;
	else
	 	dir = q->debugfs_dir;

in do_blk_trace_setup.