Re: [PATCH 14/26] md: convert to blk_alloc_disk/blk_cleanup_disk

From: Hannes Reinecke <hare@suse.de>
To: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Chris Zankel <chris@zankel.net>,
	Max Filippov <jcmvbkbc@gmail.com>,
	Philipp Reisner <philipp.reisner@linbit.com>,
	Lars Ellenberg <lars.ellenberg@linbit.com>,
	Jim Paris <jim@jtan.com>,
	Joshua Morris <josh.h.morris@us.ibm.com>,
	Philip Kelleher <pjk1939@linux.ibm.com>,
	Minchan Kim <minchan@kernel.org>, Nitin Gupta <ngupta@vflare.org>,
	Matias Bjorling <mb@lightnvm.io>, Coly Li <colyli@suse.de>,
	Mike Snitzer <snitzer@redhat.com>, Song Liu <song@kernel.org>,
	Maxim Levitsky <maximlevitsky@gmail.com>,
	Alex Dubov <oakad@yahoo.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>
Cc: linux-block@vger.kernel.org, dm-devel@redhat.com,
	linux-m68k@lists.linux-m68k.org, linux-xtensa@linux-xtensa.org,
	drbd-dev@lists.linbit.com, linuxppc-dev@lists.ozlabs.org,
	linux-bcache@vger.kernel.org, linux-raid@vger.kernel.org,
	linux-mmc@vger.kernel.org, nvdimm@lists.linux.dev,
	linux-nvme@lists.infradead.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH 14/26] md: convert to blk_alloc_disk/blk_cleanup_disk
Date: Sun, 23 May 2021 10:12:49 +0200	[thread overview]
Message-ID: <e65de9e6-337c-3e41-b5c2-d033ff236582@suse.de> (raw)
In-Reply-To: <20210521055116.1053587-15-hch@lst.de>

On 5/21/21 7:51 AM, Christoph Hellwig wrote:
> Convert the md 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/md/md.c | 25 +++++++++----------------
>   1 file changed, 9 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 49f897fbb89b..d806be8cc210 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -5598,12 +5598,10 @@ static void md_free(struct kobject *ko)
>   	if (mddev->sysfs_level)
>   		sysfs_put(mddev->sysfs_level);
>   
> -	if (mddev->gendisk)
> +	if (mddev->gendisk) {
>   		del_gendisk(mddev->gendisk);
> -	if (mddev->queue)
> -		blk_cleanup_queue(mddev->queue);
> -	if (mddev->gendisk)
> -		put_disk(mddev->gendisk);
> +		blk_cleanup_disk(mddev->gendisk);
> +	}
>   	percpu_ref_exit(&mddev->writes_pending);
>   
>   	bioset_exit(&mddev->bio_set);
> @@ -5711,20 +5709,13 @@ static int md_alloc(dev_t dev, char *name)
>   		goto abort;
>   
>   	error = -ENOMEM;
> -	mddev->queue = blk_alloc_queue(NUMA_NO_NODE);
> -	if (!mddev->queue)
> +	disk = blk_alloc_disk(NUMA_NO_NODE);
> +	if (!disk)
>   		goto abort;
>   
> -	blk_set_stacking_limits(&mddev->queue->limits);
> -
> -	disk = alloc_disk(1 << shift);
> -	if (!disk) {
> -		blk_cleanup_queue(mddev->queue);
> -		mddev->queue = NULL;
> -		goto abort;
> -	}
>   	disk->major = MAJOR(mddev->unit);
>   	disk->first_minor = unit << shift;
> +	disk->minors = 1 << shift;
>   	if (name)
>   		strcpy(disk->disk_name, name);
>   	else if (partitioned)
> @@ -5733,7 +5724,9 @@ static int md_alloc(dev_t dev, char *name)
>   		sprintf(disk->disk_name, "md%d", unit);
>   	disk->fops = &md_fops;
>   	disk->private_data = mddev;
> -	disk->queue = mddev->queue;
> +
> +	mddev->queue = disk->queue;
> +	blk_set_stacking_limits(&mddev->queue->limits);
>   	blk_queue_write_cache(mddev->queue, true, true);
>   	/* Allow extended partitions.  This makes the
>   	 * 'mdp' device redundant, but we can't really
> 
Wouldn't it make sense to introduce a helper 'blk_queue_from_disk()' or 
somesuch to avoid having to keep an explicit 'queue' pointer?


Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
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