1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/vmalloc.h>
5 /* zone_size in MBs to sectors. */
6 #define ZONE_SIZE_SHIFT 11
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_size = (sector_t)dev->size * 1024 * 1024;
19 if (!is_power_of_2(dev->zone_size)) {
20 pr_err("null_blk: zone_size must be power-of-two\n");
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);
32 for (i = 0; i < dev->nr_zones; i++) {
33 struct blk_zone *zone = &dev->zones[i];
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;
40 sector += dev->zone_size_sects;
46 void null_zone_exit(struct nullb_device *dev)
51 static void null_zone_fill_rq(struct nullb_device *dev, struct request *rq,
52 unsigned int zno, unsigned int nr_zones)
54 struct blk_zone_report_hdr *hdr = NULL;
56 struct bvec_iter iter;
58 unsigned int zones_to_cpy;
60 bio_for_each_segment(bvec, rq->bio, iter) {
61 addr = kmap_atomic(bvec.bv_page);
63 zones_to_cpy = bvec.bv_len / sizeof(struct blk_zone);
66 hdr = (struct blk_zone_report_hdr *)addr;
67 hdr->nr_zones = nr_zones;
69 addr += sizeof(struct blk_zone_report_hdr);
72 zones_to_cpy = min_t(unsigned int, zones_to_cpy, nr_zones);
74 memcpy(addr, &dev->zones[zno],
75 zones_to_cpy * sizeof(struct blk_zone));
79 nr_zones -= zones_to_cpy;
87 blk_status_t null_zone_report(struct nullb *nullb,
88 struct nullb_cmd *cmd)
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;
97 nr_zones = min_t(unsigned int, nr_zones, max_zones);
99 null_zone_fill_rq(nullb->dev, rq, zno, nr_zones);
104 void null_zone_write(struct nullb_cmd *cmd)
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];
113 switch (zone->cond) {
114 case BLK_ZONE_COND_FULL:
115 /* Cannot write to a full zone */
116 cmd->error = BLK_STS_IOERR;
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;
126 if (zone->cond == BLK_ZONE_COND_EMPTY)
127 zone->cond = BLK_ZONE_COND_IMP_OPEN;
129 zone->wp += rq_sectors;
130 if (zone->wp == zone->start + zone->len)
131 zone->cond = BLK_ZONE_COND_FULL;
134 /* Invalid zone condition */
135 cmd->error = BLK_STS_IOERR;
140 void null_zone_reset(struct nullb_cmd *cmd)
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];
147 zone->cond = BLK_ZONE_COND_EMPTY;
148 zone->wp = zone->start;