Re: [PATCH v5 04/10] blk-mq: Only unregister hctxs for which registration succeeded

Omar Sandoval
2017-04-25T21:18:16Z

On Tue, Apr 25, 2017 at 01:37:39PM -0700, Bart Van Assche wrote:
> Hctx unregistration involves calling kobject_del(). kobject_del()
> must not be called if kobject_add() has not been called. Hence in
> the error path only unregister hctxs for which registration succeeded.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Cc: Omar Sandoval <osandov@fb.com>
> Cc: Hannes Reinecke <hare@suse.com>
> ---
> block/blk-mq-sysfs.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
> index c2cac20d981d..053549a32778 100644
> --- a/block/blk-mq-sysfs.c
> +++ b/block/blk-mq-sysfs.c
> @@ -323,16 +323,24 @@ int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
> queue_for_each_hw_ctx(q, hctx, i) {
> ret = blk_mq_register_hctx(hctx);
> if (ret)
> - break;
> + goto unreg;
> }
>
> - if (ret)
> - __blk_mq_unregister_dev(dev, q);
> - else
> - q->mq_sysfs_init_done = true;
> + q->mq_sysfs_init_done = true;
>
> out:
> return ret;
> +
> +unreg:
> + while (--i >= 0)
> + blk_mq_unregister_hctx(hctx);

Missed this in your last submission, won't this unregister the same hctx
repeatedly?

> + blk_mq_debugfs_unregister_mq(q);
> +
> + kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
> + kobject_del(&q->mq_kobj);
> + kobject_put(&dev->kobj);
> + goto out;

The out label doesn't do anything interesting, can we just return ret?

> }
>
> int blk_mq_register_dev(struct device *dev, struct request_queue *q)
> --
> 2.12.2
>