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Commit 6ac93117 authored by Omar Sandoval's avatar Omar Sandoval Committed by Jens Axboe
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blktrace: use existing disk debugfs directory 



We may already have a directory to put the blktrace stuff in if

1. The disk uses blk-mq
2. CONFIG_BLK_DEBUG_FS is enabled
3. We are tracing the whole disk and not a partition

Instead of hardcoding this very specific case, let's use the new
debugfs_lookup(). If the directory exists, we use it, otherwise we
create one and clean it up later.

Fixes: 07e4fead ("blk-mq: create debugfs directory tree")
Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 62ebce16

kernel/trace/blktrace.c

+8 −5
Original line number Diff line number Diff line
@@ -470,12 +470,12 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
	if (!blk_debugfs_root)

		goto err;



	dir = debugfs_create_dir(buts->name, blk_debugfs_root);



	dir = debugfs_lookup(buts->name, blk_debugfs_root);

	if (!dir)

		bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);

	if (!dir)

		goto err;



	bt->dir = dir;

	bt->dev = dev;

	atomic_set(&bt->dropped, 0);

	INIT_LIST_HEAD(&bt->running_list);
@@ -517,8 +517,11 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
	if (atomic_inc_return(&blk_probes_ref) == 1)

		blk_register_tracepoints();



	return 0;

	ret = 0;

err:

	if (dir && !bt->dir)

		dput(dir);

	if (ret)

		blk_trace_free(bt);

	return ret;

}