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Adds support for exposing a null_blk device through the zone device interface. The interface is managed with the parameters zoned and zone_size. If zoned is set, the null_blk instance registers as a zoned block device. The zone_size parameter defines how big each zone will be. Signed-off-by: Matias Bjørling <[email protected]> Signed-off-by: Bart Van Assche <[email protected]> Signed-off-by: Damien Le Moal <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
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// SPDX-License-Identifier: GPL-2.0 | ||
#include <linux/vmalloc.h> | ||
#include "null_blk.h" | ||
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/* zone_size in MBs to sectors. */ | ||
#define ZONE_SIZE_SHIFT 11 | ||
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static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect) | ||
{ | ||
return sect >> ilog2(dev->zone_size_sects); | ||
} | ||
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int null_zone_init(struct nullb_device *dev) | ||
{ | ||
sector_t dev_size = (sector_t)dev->size * 1024 * 1024; | ||
sector_t sector = 0; | ||
unsigned int i; | ||
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if (!is_power_of_2(dev->zone_size)) { | ||
pr_err("null_blk: zone_size must be power-of-two\n"); | ||
return -EINVAL; | ||
} | ||
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dev->zone_size_sects = dev->zone_size << ZONE_SIZE_SHIFT; | ||
dev->nr_zones = dev_size >> | ||
(SECTOR_SHIFT + ilog2(dev->zone_size_sects)); | ||
dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct blk_zone), | ||
GFP_KERNEL | __GFP_ZERO); | ||
if (!dev->zones) | ||
return -ENOMEM; | ||
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for (i = 0; i < dev->nr_zones; i++) { | ||
struct blk_zone *zone = &dev->zones[i]; | ||
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zone->start = zone->wp = sector; | ||
zone->len = dev->zone_size_sects; | ||
zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ; | ||
zone->cond = BLK_ZONE_COND_EMPTY; | ||
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sector += dev->zone_size_sects; | ||
} | ||
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return 0; | ||
} | ||
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void null_zone_exit(struct nullb_device *dev) | ||
{ | ||
kvfree(dev->zones); | ||
} | ||
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static void null_zone_fill_rq(struct nullb_device *dev, struct request *rq, | ||
unsigned int zno, unsigned int nr_zones) | ||
{ | ||
struct blk_zone_report_hdr *hdr = NULL; | ||
struct bio_vec bvec; | ||
struct bvec_iter iter; | ||
void *addr; | ||
unsigned int zones_to_cpy; | ||
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bio_for_each_segment(bvec, rq->bio, iter) { | ||
addr = kmap_atomic(bvec.bv_page); | ||
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zones_to_cpy = bvec.bv_len / sizeof(struct blk_zone); | ||
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if (!hdr) { | ||
hdr = (struct blk_zone_report_hdr *)addr; | ||
hdr->nr_zones = nr_zones; | ||
zones_to_cpy--; | ||
addr += sizeof(struct blk_zone_report_hdr); | ||
} | ||
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zones_to_cpy = min_t(unsigned int, zones_to_cpy, nr_zones); | ||
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memcpy(addr, &dev->zones[zno], | ||
zones_to_cpy * sizeof(struct blk_zone)); | ||
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kunmap_atomic(addr); | ||
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nr_zones -= zones_to_cpy; | ||
zno += zones_to_cpy; | ||
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if (!nr_zones) | ||
break; | ||
} | ||
} | ||
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blk_status_t null_zone_report(struct nullb *nullb, | ||
struct nullb_cmd *cmd) | ||
{ | ||
struct nullb_device *dev = nullb->dev; | ||
struct request *rq = cmd->rq; | ||
unsigned int zno = null_zone_no(dev, blk_rq_pos(rq)); | ||
unsigned int nr_zones = dev->nr_zones - zno; | ||
unsigned int max_zones = (blk_rq_bytes(rq) / | ||
sizeof(struct blk_zone)) - 1; | ||
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nr_zones = min_t(unsigned int, nr_zones, max_zones); | ||
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null_zone_fill_rq(nullb->dev, rq, zno, nr_zones); | ||
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return BLK_STS_OK; | ||
} | ||
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void null_zone_write(struct nullb_cmd *cmd) | ||
{ | ||
struct nullb_device *dev = cmd->nq->dev; | ||
struct request *rq = cmd->rq; | ||
sector_t sector = blk_rq_pos(rq); | ||
unsigned int rq_sectors = blk_rq_sectors(rq); | ||
unsigned int zno = null_zone_no(dev, sector); | ||
struct blk_zone *zone = &dev->zones[zno]; | ||
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switch (zone->cond) { | ||
case BLK_ZONE_COND_FULL: | ||
/* Cannot write to a full zone */ | ||
cmd->error = BLK_STS_IOERR; | ||
break; | ||
case BLK_ZONE_COND_EMPTY: | ||
case BLK_ZONE_COND_IMP_OPEN: | ||
/* Writes must be at the write pointer position */ | ||
if (blk_rq_pos(rq) != zone->wp) { | ||
cmd->error = BLK_STS_IOERR; | ||
break; | ||
} | ||
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if (zone->cond == BLK_ZONE_COND_EMPTY) | ||
zone->cond = BLK_ZONE_COND_IMP_OPEN; | ||
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zone->wp += rq_sectors; | ||
if (zone->wp == zone->start + zone->len) | ||
zone->cond = BLK_ZONE_COND_FULL; | ||
break; | ||
default: | ||
/* Invalid zone condition */ | ||
cmd->error = BLK_STS_IOERR; | ||
break; | ||
} | ||
} | ||
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void null_zone_reset(struct nullb_cmd *cmd) | ||
{ | ||
struct nullb_device *dev = cmd->nq->dev; | ||
struct request *rq = cmd->rq; | ||
unsigned int zno = null_zone_no(dev, blk_rq_pos(rq)); | ||
struct blk_zone *zone = &dev->zones[zno]; | ||
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zone->cond = BLK_ZONE_COND_EMPTY; | ||
zone->wp = zone->start; | ||
} |