blktrace: use existing disk debugfs directory (6ac93117) · Commits · 戴 / test

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: ("blk-mq: create debugfs directory tree") Signed-off-by:

Omar Sandoval <osandov@fb.com> Signed-off-by:

Jens Axboe <axboe@fb.com>

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;
		}

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