Re: [PATCH] block: rename 'q->debugfs_dir' in blk_unregister_queue()

[yukuai (C)]

On 2020/2/12 11:27, Bart Van Assche wrote:
> What is the behavior of this loop if multiple block devices are being
> removed concurrently? Does it perhaps change remove block device removal
> from an O(1) into an O(n) operation?
Yes, there may be performance overhead.(I thought it's minimal) However,
I can change the name of dir form "read_to_remove_%d" to
"read_to_remove_%s(dev_name)_%d" to fix that.
> Since this scenario may only matter to syzbot tests: has it been
> considered to delay block device creation if the debugfs directory from
> a previous incarnation of the block device still exists?
I think it's a bug device creation succeed when the debugfs directory
exist. Of course delay block device creation can fix the problem, but I
haven't come up with a good solution. And by renaming the dir, there is
no need to delay cration.

Thanks!
Yu Kuai