drivers/block/null_blk_zoned.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/vmalloc.h>
   3 #include "null_blk.h"
   4
   5 /* zone_size in MBs to sectors. */
   6 #define ZONE_SIZE_SHIFT         11
   7
   8 static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect)
   9 {
  10         return sect >> ilog2(dev->zone_size_sects);
  11 }
  12
  13 int null_zone_init(struct nullb_device *dev)
  14 {
  15         sector_t dev_size = (sector_t)dev->size * 1024 * 1024;
  16         sector_t sector = 0;
  17         unsigned int i;
  18
  19         if (!is_power_of_2(dev->zone_size)) {
  20                 pr_err("null_blk: zone_size must be power-of-two\n");
  21                 return -EINVAL;
  22         }
  23
  24         dev->zone_size_sects = dev->zone_size << ZONE_SIZE_SHIFT;
  25         dev->nr_zones = dev_size >>
  26                                 (SECTOR_SHIFT + ilog2(dev->zone_size_sects));
  27         dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct blk_zone),
  28                         GFP_KERNEL | __GFP_ZERO);
  29         if (!dev->zones)
  30                 return -ENOMEM;
  31
  32         for (i = 0; i < dev->nr_zones; i++) {
  33                 struct blk_zone *zone = &dev->zones[i];
  34
  35                 zone->start = zone->wp = sector;
  36                 zone->len = dev->zone_size_sects;
  37                 zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ;
  38                 zone->cond = BLK_ZONE_COND_EMPTY;
  39
  40                 sector += dev->zone_size_sects;
  41         }
  42
  43         return 0;
  44 }
  45
  46 void null_zone_exit(struct nullb_device *dev)
  47 {
  48         kvfree(dev->zones);
  49 }
  50
  51 static void null_zone_fill_rq(struct nullb_device *dev, struct request *rq,
  52                               unsigned int zno, unsigned int nr_zones)
  53 {
  54         struct blk_zone_report_hdr *hdr = NULL;
  55         struct bio_vec bvec;
  56         struct bvec_iter iter;
  57         void *addr;
  58         unsigned int zones_to_cpy;
  59
  60         bio_for_each_segment(bvec, rq->bio, iter) {
  61                 addr = kmap_atomic(bvec.bv_page);
  62
  63                 zones_to_cpy = bvec.bv_len / sizeof(struct blk_zone);
  64
  65                 if (!hdr) {
  66                         hdr = (struct blk_zone_report_hdr *)addr;
  67                         hdr->nr_zones = nr_zones;
  68                         zones_to_cpy--;
  69                         addr += sizeof(struct blk_zone_report_hdr);
  70                 }
  71
  72                 zones_to_cpy = min_t(unsigned int, zones_to_cpy, nr_zones);
  73
  74                 memcpy(addr, &dev->zones[zno],
  75                                 zones_to_cpy * sizeof(struct blk_zone));
  76
  77                 kunmap_atomic(addr);
  78
  79                 nr_zones -= zones_to_cpy;
  80                 zno += zones_to_cpy;
  81
  82                 if (!nr_zones)
  83                         break;
  84         }
  85 }
  86
  87 blk_status_t null_zone_report(struct nullb *nullb,
  88                                      struct nullb_cmd *cmd)
  89 {
  90         struct nullb_device *dev = nullb->dev;
  91         struct request *rq = cmd->rq;
  92         unsigned int zno = null_zone_no(dev, blk_rq_pos(rq));
  93         unsigned int nr_zones = dev->nr_zones - zno;
  94         unsigned int max_zones = (blk_rq_bytes(rq) /
  95                                         sizeof(struct blk_zone)) - 1;
  96
  97         nr_zones = min_t(unsigned int, nr_zones, max_zones);
  98
  99         null_zone_fill_rq(nullb->dev, rq, zno, nr_zones);
 100
 101         return BLK_STS_OK;
 102 }
 103
 104 void null_zone_write(struct nullb_cmd *cmd)
 105 {
 106         struct nullb_device *dev = cmd->nq->dev;
 107         struct request *rq = cmd->rq;
 108         sector_t sector = blk_rq_pos(rq);
 109         unsigned int rq_sectors = blk_rq_sectors(rq);
 110         unsigned int zno = null_zone_no(dev, sector);
 111         struct blk_zone *zone = &dev->zones[zno];
 112
 113         switch (zone->cond) {
 114         case BLK_ZONE_COND_FULL:
 115                 /* Cannot write to a full zone */
 116                 cmd->error = BLK_STS_IOERR;
 117                 break;
 118         case BLK_ZONE_COND_EMPTY:
 119         case BLK_ZONE_COND_IMP_OPEN:
 120                 /* Writes must be at the write pointer position */
 121                 if (blk_rq_pos(rq) != zone->wp) {
 122                         cmd->error = BLK_STS_IOERR;
 123                         break;
 124                 }
 125
 126                 if (zone->cond == BLK_ZONE_COND_EMPTY)
 127                         zone->cond = BLK_ZONE_COND_IMP_OPEN;
 128
 129                 zone->wp += rq_sectors;
 130                 if (zone->wp == zone->start + zone->len)
 131                         zone->cond = BLK_ZONE_COND_FULL;
 132                 break;
 133         default:
 134                 /* Invalid zone condition */
 135                 cmd->error = BLK_STS_IOERR;
 136                 break;
 137         }
 138 }
 139
 140 void null_zone_reset(struct nullb_cmd *cmd)
 141 {
 142         struct nullb_device *dev = cmd->nq->dev;
 143         struct request *rq = cmd->rq;
 144         unsigned int zno = null_zone_no(dev, blk_rq_pos(rq));
 145         struct blk_zone *zone = &dev->zones[zno];
 146
 147         zone->cond = BLK_ZONE_COND_EMPTY;
 148         zone->wp = zone->start;
 149 }