1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/vmalloc.h>
3 #include <linux/sizes.h>
6 #define MB_TO_SECTS(mb) (((sector_t)mb * SZ_1M) >> SECTOR_SHIFT)
8 static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect)
10 return sect >> ilog2(dev->zone_size_sects);
13 int null_zone_init(struct nullb_device *dev)
15 sector_t dev_capacity_sects;
19 if (!is_power_of_2(dev->zone_size)) {
20 pr_err("null_blk: zone_size must be power-of-two\n");
23 if (dev->zone_size > dev->size) {
24 pr_err("Zone size larger than device capacity\n");
28 dev_capacity_sects = MB_TO_SECTS(dev->size);
29 dev->zone_size_sects = MB_TO_SECTS(dev->zone_size);
30 dev->nr_zones = dev_capacity_sects >> ilog2(dev->zone_size_sects);
31 if (dev_capacity_sects & (dev->zone_size_sects - 1))
34 dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct blk_zone),
35 GFP_KERNEL | __GFP_ZERO);
39 for (i = 0; i < dev->nr_zones; i++) {
40 struct blk_zone *zone = &dev->zones[i];
42 zone->start = zone->wp = sector;
43 if (zone->start + dev->zone_size_sects > dev_capacity_sects)
44 zone->len = dev_capacity_sects - zone->start;
46 zone->len = dev->zone_size_sects;
47 zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ;
48 zone->cond = BLK_ZONE_COND_EMPTY;
50 sector += dev->zone_size_sects;
56 void null_zone_exit(struct nullb_device *dev)
62 static void null_zone_fill_bio(struct nullb_device *dev, struct bio *bio,
63 unsigned int zno, unsigned int nr_zones)
65 struct blk_zone_report_hdr *hdr = NULL;
67 struct bvec_iter iter;
69 unsigned int zones_to_cpy;
71 bio_for_each_segment(bvec, bio, iter) {
72 addr = kmap_atomic(bvec.bv_page);
74 zones_to_cpy = bvec.bv_len / sizeof(struct blk_zone);
77 hdr = (struct blk_zone_report_hdr *)addr;
78 hdr->nr_zones = nr_zones;
80 addr += sizeof(struct blk_zone_report_hdr);
83 zones_to_cpy = min_t(unsigned int, zones_to_cpy, nr_zones);
85 memcpy(addr, &dev->zones[zno],
86 zones_to_cpy * sizeof(struct blk_zone));
90 nr_zones -= zones_to_cpy;
98 blk_status_t null_zone_report(struct nullb *nullb, struct bio *bio)
100 struct nullb_device *dev = nullb->dev;
101 unsigned int zno = null_zone_no(dev, bio->bi_iter.bi_sector);
102 unsigned int nr_zones = dev->nr_zones - zno;
103 unsigned int max_zones;
105 max_zones = (bio->bi_iter.bi_size / sizeof(struct blk_zone)) - 1;
106 nr_zones = min_t(unsigned int, nr_zones, max_zones);
107 null_zone_fill_bio(nullb->dev, bio, zno, nr_zones);
112 void null_zone_write(struct nullb_cmd *cmd, sector_t sector,
113 unsigned int nr_sectors)
115 struct nullb_device *dev = cmd->nq->dev;
116 unsigned int zno = null_zone_no(dev, sector);
117 struct blk_zone *zone = &dev->zones[zno];
119 switch (zone->cond) {
120 case BLK_ZONE_COND_FULL:
121 /* Cannot write to a full zone */
122 cmd->error = BLK_STS_IOERR;
124 case BLK_ZONE_COND_EMPTY:
125 case BLK_ZONE_COND_IMP_OPEN:
126 /* Writes must be at the write pointer position */
127 if (sector != zone->wp) {
128 cmd->error = BLK_STS_IOERR;
132 if (zone->cond == BLK_ZONE_COND_EMPTY)
133 zone->cond = BLK_ZONE_COND_IMP_OPEN;
135 zone->wp += nr_sectors;
136 if (zone->wp == zone->start + zone->len)
137 zone->cond = BLK_ZONE_COND_FULL;
140 /* Invalid zone condition */
141 cmd->error = BLK_STS_IOERR;
146 void null_zone_reset(struct nullb_cmd *cmd, sector_t sector)
148 struct nullb_device *dev = cmd->nq->dev;
149 unsigned int zno = null_zone_no(dev, sector);
150 struct blk_zone *zone = &dev->zones[zno];
152 zone->cond = BLK_ZONE_COND_EMPTY;
153 zone->wp = zone->start;