From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Martin K. Petersen" <martin.petersen@oracle.com>
Subject: Re: [PATCH v4 11/11] block: Introduce
	blk_revalidate_disk_zones()
Date: Tue, 16 Oct 2018 01:00:16 -0400
Message-ID: <yq1r2gqtrj3.fsf@oracle.com>
References: <20181012100850.23316-1-damien.lemoal@wdc.com>
	<20181012100850.23316-12-damien.lemoal@wdc.com>
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To: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Jens Axboe <axboe@kernel.dk>, "Martin K . Petersen" <martin.petersen@oracle.com>, Mike Snitzer <snitzer@redhat.com>, linux-block@vger.kernel.org, dm-devel@redhat.com, linux-scsi@vger.kernel.org, Christoph Hellwig <hch@lst.de>, Matias Bjorling <matias.bjorling@wdc.com>
List-Id: linux-scsi@vger.kernel.org


Damien,

> Drivers exposing zoned block devices have to initialize and maintain
> correctness (i.e. revalidate) of the device zone bitmaps attached to
> the device request queue (seq_zones_bitmap and seq_zones_wlock).
>
> To simplify coding this, introduce a generic helper function
> blk_revalidate_disk_zones() suitable for most (and likely all) cases.
> This new function always update the seq_zones_bitmap and seq_zones_wlock
> bitmaps as well as the queue nr_zones field when called for a disk
> using a request based queue. For a disk using a BIO based queue, only
> the number of zones is updated since these queues do not have
> schedulers and so do not need the zone bitmaps.
>
> With this change, the zone bitmap initialization code in sd_zbc.c can be
> replaced with a call to this function in sd_zbc_read_zones(), which is
> called from the disk revalidate block operation method.
>
> A call to blk_revalidate_disk_zones() is also added to the null_blk
> driver for devices created with the zoned mode enabled.
>
> Finally, to ensure that zoned devices created with dm-linear or
> dm-flakey expose the correct number of zones through sysfs, a call to
> blk_revalidate_disk_zones() is added to dm_table_set_restrictions().
>
> The zone bitmaps allocated and initialized with
> blk_revalidate_disk_zones() are freed automatically from
> __blk_release_queue() using the block internal function
> blk_queue_free_zone_bitmaps().

Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

-- 
Martin K. Petersen	Oracle Linux Engineering