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_bio(struct nullb_device *dev, struct bio *bio,
  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, 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, struct bio *bio)
  88 {
  89         struct nullb_device *dev = nullb->dev;
  90         unsigned int zno = null_zone_no(dev, bio->bi_iter.bi_sector);
  91         unsigned int nr_zones = dev->nr_zones - zno;
  92         unsigned int max_zones;
  93
  94         max_zones = (bio->bi_iter.bi_size / sizeof(struct blk_zone)) - 1;
  95         nr_zones = min_t(unsigned int, nr_zones, max_zones);
  96         null_zone_fill_bio(nullb->dev, bio, zno, nr_zones);
  97
  98         return BLK_STS_OK;
  99 }
 100
 101 void null_zone_write(struct nullb_cmd *cmd, sector_t sector,
 102                      unsigned int nr_sectors)
 103 {
 104         struct nullb_device *dev = cmd->nq->dev;
 105         unsigned int zno = null_zone_no(dev, sector);
 106         struct blk_zone *zone = &dev->zones[zno];
 107
 108         switch (zone->cond) {
 109         case BLK_ZONE_COND_FULL:
 110                 /* Cannot write to a full zone */
 111                 cmd->error = BLK_STS_IOERR;
 112                 break;
 113         case BLK_ZONE_COND_EMPTY:
 114         case BLK_ZONE_COND_IMP_OPEN:
 115                 /* Writes must be at the write pointer position */
 116                 if (sector != zone->wp) {
 117                         cmd->error = BLK_STS_IOERR;
 118                         break;
 119                 }
 120
 121                 if (zone->cond == BLK_ZONE_COND_EMPTY)
 122                         zone->cond = BLK_ZONE_COND_IMP_OPEN;
 123
 124                 zone->wp += nr_sectors;
 125                 if (zone->wp == zone->start + zone->len)
 126                         zone->cond = BLK_ZONE_COND_FULL;
 127                 break;
 128         default:
 129                 /* Invalid zone condition */
 130                 cmd->error = BLK_STS_IOERR;
 131                 break;
 132         }
 133 }
 134
 135 void null_zone_reset(struct nullb_cmd *cmd, sector_t sector)
 136 {
 137         struct nullb_device *dev = cmd->nq->dev;
 138         unsigned int zno = null_zone_no(dev, sector);
 139         struct blk_zone *zone = &dev->zones[zno];
 140
 141         zone->cond = BLK_ZONE_COND_EMPTY;
 142         zone->wp = zone->start;
 143 }