Re: [PATCH 17/26] nvdimm-pmem: convert to blk_alloc_disk/blk_cleanup_disk

[Dan Williams <dan.j.williams@intel.com>]

[ add Sachin who reported this commit in -next ]

On Thu, May 20, 2021 at 10:52 PM Christoph Hellwig <hch@lst.de> wrote:
>
> Convert the nvdimm-pmem driver to use the blk_alloc_disk and
> blk_cleanup_disk helpers to simplify gendisk and request_queue
> allocation.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/nvdimm/pmem.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 968b8483c763..9fcd05084564 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -338,7 +338,7 @@ static void pmem_pagemap_cleanup(struct dev_pagemap *pgmap)
>         struct request_queue *q =
>                 container_of(pgmap->ref, struct request_queue, q_usage_counter);
>
> -       blk_cleanup_queue(q);
> +       blk_cleanup_disk(queue_to_disk(q));

This is broken. This comes after del_gendisk() which means the queue
device is no longer associated with its disk parent. Perhaps @pmem
could be stashed in pgmap->owner and then this can use pmem->disk? Not
see any other readily available ways to get back to the disk from here
after del_gendisk().