Messages in this thread | | | Date | Fri, 26 Aug 2022 14:09:22 -0600 | Subject | Re: [PATCH v12 03/13] block: allow blk-zoned devices to have non-power-of-2 zone size | From | Jonathan Derrick <> |
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On 8/26/2022 2:06 PM, Jonathan Derrick wrote: > > > On 8/23/2022 6:18 AM, Pankaj Raghav wrote: >> Checking if a given sector is aligned to a zone is a common >> operation that is performed for zoned devices. Add >> bdev_is_zone_start helper to check for this instead of opencoding it >> everywhere. >> >> Convert the calculations on zone size to be generic instead of relying on >> power-of-2(po2) based arithmetic in the block layer using the helpers >> wherever possible. >> >> The only hot path affected by this change for zoned devices with po2 >> zone size is in blk_check_zone_append() but bdev_is_zone_start() >> helper is >> used to optimize the calculation for po2 zone sizes. >> >> Finally, allow zoned devices with non po2 zone sizes provided that their >> zone capacity and zone size are equal. The main motivation to allow zoned >> devices with non po2 zone size is to remove the unmapped LBA between >> zone capcity and zone size for devices that cannot have a po2 zone >> capacity. >> >> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> >> Reviewed-by: Hannes Reinecke <hare@suse.de> >> Reviewed-by: Bart Van Assche <bvanassche@acm.org> >> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> >> --- >> block/blk-core.c | 2 +- >> block/blk-zoned.c | 24 ++++++++++++++++++------ >> include/linux/blkdev.h | 30 ++++++++++++++++++++++++++++++ >> 3 files changed, 49 insertions(+), 7 deletions(-) >> >> diff --git a/block/blk-core.c b/block/blk-core.c >> index a0d1104c5590..1cb519220ffb 100644 >> --- a/block/blk-core.c >> +++ b/block/blk-core.c >> @@ -563,7 +563,7 @@ static inline blk_status_t >> blk_check_zone_append(struct request_queue *q, >> return BLK_STS_NOTSUPP; >> /* The bio sector must point to the start of a sequential zone */ >> - if (bio->bi_iter.bi_sector & (bdev_zone_sectors(bio->bi_bdev) - >> 1) || >> + if (!bdev_is_zone_start(bio->bi_bdev, bio->bi_iter.bi_sector) || >> !bio_zone_is_seq(bio)) >> return BLK_STS_IOERR; >> diff --git a/block/blk-zoned.c b/block/blk-zoned.c >> index dce9c95b4bcd..6806c69c81dc 100644 >> --- a/block/blk-zoned.c >> +++ b/block/blk-zoned.c >> @@ -285,10 +285,10 @@ int blkdev_zone_mgmt(struct block_device *bdev, >> enum req_op op, >> return -EINVAL; >> /* Check alignment (handle eventual smaller last zone) */ >> - if (sector & (zone_sectors - 1)) >> + if (!bdev_is_zone_start(bdev, sector)) >> return -EINVAL; >> - if ((nr_sectors & (zone_sectors - 1)) && end_sector != capacity) >> + if (!bdev_is_zone_start(bdev, nr_sectors) && end_sector != capacity) >> return -EINVAL; >> /* >> @@ -486,14 +486,26 @@ static int blk_revalidate_zone_cb(struct >> blk_zone *zone, unsigned int idx, >> * smaller last zone. >> */ >> if (zone->start == 0) { >> - if (zone->len == 0 || !is_power_of_2(zone->len)) { >> - pr_warn("%s: Invalid zoned device with non power of two >> zone size (%llu)\n", >> - disk->disk_name, zone->len); >> + if (zone->len == 0) { >> + pr_warn("%s: Invalid zero zone size", disk->disk_name); >> + return -ENODEV; >> + } >> + >> + /* >> + * Non power-of-2 zone size support was added to remove the >> + * gap between zone capacity and zone size. Though it is >> technically >> + * possible to have gaps in a non power-of-2 device, Linux >> requires >> + * the zone size to be equal to zone capacity for non power-of-2 >> + * zoned devices. >> + */ >> + if (!is_power_of_2(zone->len) && zone->capacity < zone->len) { >> + pr_err("%s: Invalid zone capacity %lld with non >> power-of-2 zone size %lld", >> + disk->disk_name, zone->capacity, zone->len); >> return -ENODEV; >> } >> args->zone_sectors = zone->len; >> - args->nr_zones = (capacity + zone->len - 1) >> ilog2(zone->len); >> + args->nr_zones = div64_u64(capacity + zone->len - 1, zone->len); >> } else if (zone->start + args->zone_sectors < capacity) { >> if (zone->len != args->zone_sectors) { >> pr_warn("%s: Invalid zoned device with non constant zone >> size\n", >> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h >> index 84e7881262e3..d0d66a0db224 100644 >> --- a/include/linux/blkdev.h >> +++ b/include/linux/blkdev.h >> @@ -704,6 +704,30 @@ static inline unsigned int disk_zone_no(struct >> gendisk *disk, sector_t sector) >> return div64_u64(sector, zone_sectors); >> } >> +static inline sector_t bdev_offset_from_zone_start(struct >> block_device *bdev, >> + sector_t sec) >> +{ >> + sector_t zone_sectors = bdev_zone_sectors(bdev); >> + u64 remainder = 0; >> + >> + if (!bdev_is_zoned(bdev)) >> + return 0; > See below > >> + >> + if (is_power_of_2(zone_sectors)) >> + return sec & (zone_sectors - 1); >> + >> + div64_u64_rem(sec, zone_sectors, &remainder); >> + return remainder; >> +} >> + >> +static inline bool bdev_is_zone_start(struct block_device *bdev, >> sector_t sec) >> +{ >> + if (!bdev_is_zoned(bdev)) >> + return false; > Duplicating the same check above, and the check above is less clear in > the case of !zoned since it returns 0 and not some warning that makes > sense in the case of zoned check on !zoned bdev. > Can you simply exclude above check? Nevermind, just noticed bdev_offset_from_zone_start is used in later patches.
> > >> + >> + return bdev_offset_from_zone_start(bdev, sec) == 0; >> +} >> + >> static inline bool disk_zone_is_seq(struct gendisk *disk, sector_t >> sector) >> { >> if (!blk_queue_is_zoned(disk->queue)) >> @@ -748,6 +772,12 @@ static inline unsigned int disk_zone_no(struct >> gendisk *disk, sector_t sector) >> { >> return 0; >> } >> + >> +static inline bool bdev_is_zone_start(struct block_device *bdev, >> sector_t sec) >> +{ >> + return false; >> +} >> + >> static inline unsigned int bdev_max_open_zones(struct block_device >> *bdev) >> { >> return 0;
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