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         if (dev->zone_size > dev->size) {
  24                 pr_err("Zone size larger than device capacity\n");
  25                 return -EINVAL;
  26         }
  27
  28         dev->zone_size_sects = dev->zone_size << ZONE_SIZE_SHIFT;
  29         dev->nr_zones = dev_size >>
  30                                 (SECTOR_SHIFT + ilog2(dev->zone_size_sects));
  31         dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct blk_zone),
  32                         GFP_KERNEL | __GFP_ZERO);
  33         if (!dev->zones)
  34                 return -ENOMEM;
  35
  36         for (i = 0; i < dev->nr_zones; i++) {
  37                 struct blk_zone *zone = &dev->zones[i];
  38
  39                 zone->start = zone->wp = sector;
  40                 zone->len = dev->zone_size_sects;
  41                 zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ;
  42                 zone->cond = BLK_ZONE_COND_EMPTY;
  43
  44                 sector += dev->zone_size_sects;
  45         }
  46
  47         return 0;
  48 }
  49
  50 void null_zone_exit(struct nullb_device *dev)
  51 {
  52         kvfree(dev->zones);
  53 }
  54
  55 static void null_zone_fill_bio(struct nullb_device *dev, struct bio *bio,
  56                                unsigned int zno, unsigned int nr_zones)
  57 {
  58         struct blk_zone_report_hdr *hdr = NULL;
  59         struct bio_vec bvec;
  60         struct bvec_iter iter;
  61         void *addr;
  62         unsigned int zones_to_cpy;
  63
  64         bio_for_each_segment(bvec, bio, iter) {
  65                 addr = kmap_atomic(bvec.bv_page);
  66
  67                 zones_to_cpy = bvec.bv_len / sizeof(struct blk_zone);
  68
  69                 if (!hdr) {
  70                         hdr = (struct blk_zone_report_hdr *)addr;
  71                         hdr->nr_zones = nr_zones;
  72                         zones_to_cpy--;
  73                         addr += sizeof(struct blk_zone_report_hdr);
  74                 }
  75
  76                 zones_to_cpy = min_t(unsigned int, zones_to_cpy, nr_zones);
  77
  78                 memcpy(addr, &dev->zones[zno],
  79                                 zones_to_cpy * sizeof(struct blk_zone));
  80
  81                 kunmap_atomic(addr);
  82
  83                 nr_zones -= zones_to_cpy;
  84                 zno += zones_to_cpy;
  85
  86                 if (!nr_zones)
  87                         break;
  88         }
  89 }
  90
  91 blk_status_t null_zone_report(struct nullb *nullb, struct bio *bio)
  92 {
  93         struct nullb_device *dev = nullb->dev;
  94         unsigned int zno = null_zone_no(dev, bio->bi_iter.bi_sector);
  95         unsigned int nr_zones = dev->nr_zones - zno;
  96         unsigned int max_zones;
  97
  98         max_zones = (bio->bi_iter.bi_size / sizeof(struct blk_zone)) - 1;
  99         nr_zones = min_t(unsigned int, nr_zones, max_zones);
 100         null_zone_fill_bio(nullb->dev, bio, zno, nr_zones);
 101
 102         return BLK_STS_OK;
 103 }
 104
 105 void null_zone_write(struct nullb_cmd *cmd, sector_t sector,
 106                      unsigned int nr_sectors)
 107 {
 108         struct nullb_device *dev = cmd->nq->dev;
 109         unsigned int zno = null_zone_no(dev, sector);
 110         struct blk_zone *zone = &dev->zones[zno];
 111
 112         switch (zone->cond) {
 113         case BLK_ZONE_COND_FULL:
 114                 /* Cannot write to a full zone */
 115                 cmd->error = BLK_STS_IOERR;
 116                 break;
 117         case BLK_ZONE_COND_EMPTY:
 118         case BLK_ZONE_COND_IMP_OPEN:
 119                 /* Writes must be at the write pointer position */
 120                 if (sector != zone->wp) {
 121                         cmd->error = BLK_STS_IOERR;
 122                         break;
 123                 }
 124
 125                 if (zone->cond == BLK_ZONE_COND_EMPTY)
 126                         zone->cond = BLK_ZONE_COND_IMP_OPEN;
 127
 128                 zone->wp += nr_sectors;
 129                 if (zone->wp == zone->start + zone->len)
 130                         zone->cond = BLK_ZONE_COND_FULL;
 131                 break;
 132         default:
 133                 /* Invalid zone condition */
 134                 cmd->error = BLK_STS_IOERR;
 135                 break;
 136         }
 137 }
 138
 139 void null_zone_reset(struct nullb_cmd *cmd, sector_t sector)
 140 {
 141         struct nullb_device *dev = cmd->nq->dev;
 142         unsigned int zno = null_zone_no(dev, sector);
 143         struct blk_zone *zone = &dev->zones[zno];
 144
 145         zone->cond = BLK_ZONE_COND_EMPTY;
 146         zone->wp = zone->start;
 147 }