150 строки
3.5 KiB
C
150 строки
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/vmalloc.h>
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#include "null_blk.h"
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/* zone_size in MBs to sectors. */
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#define ZONE_SIZE_SHIFT 11
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static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect)
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{
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return sect >> ilog2(dev->zone_size_sects);
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}
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int null_zone_init(struct nullb_device *dev)
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{
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sector_t dev_size = (sector_t)dev->size * 1024 * 1024;
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sector_t sector = 0;
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unsigned int i;
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if (!is_power_of_2(dev->zone_size)) {
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pr_err("null_blk: zone_size must be power-of-two\n");
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return -EINVAL;
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}
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dev->zone_size_sects = dev->zone_size << ZONE_SIZE_SHIFT;
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dev->nr_zones = dev_size >>
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(SECTOR_SHIFT + ilog2(dev->zone_size_sects));
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dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct blk_zone),
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GFP_KERNEL | __GFP_ZERO);
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if (!dev->zones)
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return -ENOMEM;
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for (i = 0; i < dev->nr_zones; i++) {
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struct blk_zone *zone = &dev->zones[i];
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zone->start = zone->wp = sector;
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zone->len = dev->zone_size_sects;
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zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ;
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zone->cond = BLK_ZONE_COND_EMPTY;
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sector += dev->zone_size_sects;
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}
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return 0;
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}
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void null_zone_exit(struct nullb_device *dev)
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{
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kvfree(dev->zones);
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}
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static void null_zone_fill_rq(struct nullb_device *dev, struct request *rq,
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unsigned int zno, unsigned int nr_zones)
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{
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struct blk_zone_report_hdr *hdr = NULL;
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struct bio_vec bvec;
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struct bvec_iter iter;
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void *addr;
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unsigned int zones_to_cpy;
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bio_for_each_segment(bvec, rq->bio, iter) {
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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) {
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hdr = (struct blk_zone_report_hdr *)addr;
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hdr->nr_zones = nr_zones;
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zones_to_cpy--;
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addr += sizeof(struct blk_zone_report_hdr);
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}
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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],
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zones_to_cpy * sizeof(struct blk_zone));
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kunmap_atomic(addr);
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nr_zones -= zones_to_cpy;
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zno += zones_to_cpy;
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if (!nr_zones)
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break;
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}
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}
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blk_status_t null_zone_report(struct nullb *nullb,
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struct nullb_cmd *cmd)
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{
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struct nullb_device *dev = nullb->dev;
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struct request *rq = cmd->rq;
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unsigned int zno = null_zone_no(dev, blk_rq_pos(rq));
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unsigned int nr_zones = dev->nr_zones - zno;
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unsigned int max_zones = (blk_rq_bytes(rq) /
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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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}
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void null_zone_write(struct nullb_cmd *cmd)
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{
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struct nullb_device *dev = cmd->nq->dev;
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struct request *rq = cmd->rq;
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sector_t sector = blk_rq_pos(rq);
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unsigned int rq_sectors = blk_rq_sectors(rq);
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unsigned int zno = null_zone_no(dev, sector);
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struct blk_zone *zone = &dev->zones[zno];
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switch (zone->cond) {
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case BLK_ZONE_COND_FULL:
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/* Cannot write to a full zone */
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cmd->error = BLK_STS_IOERR;
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break;
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case BLK_ZONE_COND_EMPTY:
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case BLK_ZONE_COND_IMP_OPEN:
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/* Writes must be at the write pointer position */
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if (blk_rq_pos(rq) != zone->wp) {
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cmd->error = BLK_STS_IOERR;
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break;
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}
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if (zone->cond == BLK_ZONE_COND_EMPTY)
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zone->cond = BLK_ZONE_COND_IMP_OPEN;
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zone->wp += rq_sectors;
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if (zone->wp == zone->start + zone->len)
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zone->cond = BLK_ZONE_COND_FULL;
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break;
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default:
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/* Invalid zone condition */
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cmd->error = BLK_STS_IOERR;
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break;
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}
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}
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void null_zone_reset(struct nullb_cmd *cmd)
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{
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struct nullb_device *dev = cmd->nq->dev;
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struct request *rq = cmd->rq;
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unsigned int zno = null_zone_no(dev, blk_rq_pos(rq));
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struct blk_zone *zone = &dev->zones[zno];
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zone->cond = BLK_ZONE_COND_EMPTY;
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zone->wp = zone->start;
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}
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