1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * blk-integrity.c - Block layer data integrity extensions 4 * 5 * Copyright (C) 2007, 2008 Oracle Corporation 6 * Written by: Martin K. Petersen <martin.petersen@oracle.com> 7 */ 8 9 #include <linux/blk-integrity.h> 10 #include <linux/backing-dev.h> 11 #include <linux/mempool.h> 12 #include <linux/bio.h> 13 #include <linux/scatterlist.h> 14 #include <linux/export.h> 15 #include <linux/slab.h> 16 17 #include "blk.h" 18 19 /** 20 * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements 21 * @q: request queue 22 * @bio: bio with integrity metadata attached 23 * 24 * Description: Returns the number of elements required in a 25 * scatterlist corresponding to the integrity metadata in a bio. 26 */ 27 int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio) 28 { 29 struct bio_vec iv, ivprv = { NULL }; 30 unsigned int segments = 0; 31 unsigned int seg_size = 0; 32 struct bvec_iter iter; 33 int prev = 0; 34 35 bio_for_each_integrity_vec(iv, bio, iter) { 36 37 if (prev) { 38 if (!biovec_phys_mergeable(q, &ivprv, &iv)) 39 goto new_segment; 40 if (seg_size + iv.bv_len > queue_max_segment_size(q)) 41 goto new_segment; 42 43 seg_size += iv.bv_len; 44 } else { 45 new_segment: 46 segments++; 47 seg_size = iv.bv_len; 48 } 49 50 prev = 1; 51 ivprv = iv; 52 } 53 54 return segments; 55 } 56 57 /** 58 * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist 59 * @q: request queue 60 * @bio: bio with integrity metadata attached 61 * @sglist: target scatterlist 62 * 63 * Description: Map the integrity vectors in request into a 64 * scatterlist. The scatterlist must be big enough to hold all 65 * elements. I.e. sized using blk_rq_count_integrity_sg() or 66 * rq->nr_integrity_segments. 67 */ 68 int blk_rq_map_integrity_sg(struct request *rq, struct scatterlist *sglist) 69 { 70 struct bio_vec iv, ivprv = { NULL }; 71 struct request_queue *q = rq->q; 72 struct scatterlist *sg = NULL; 73 struct bio *bio = rq->bio; 74 unsigned int segments = 0; 75 struct bvec_iter iter; 76 int prev = 0; 77 78 bio_for_each_integrity_vec(iv, bio, iter) { 79 if (prev) { 80 if (!biovec_phys_mergeable(q, &ivprv, &iv)) 81 goto new_segment; 82 if (sg->length + iv.bv_len > queue_max_segment_size(q)) 83 goto new_segment; 84 85 sg->length += iv.bv_len; 86 } else { 87 new_segment: 88 if (!sg) 89 sg = sglist; 90 else { 91 sg_unmark_end(sg); 92 sg = sg_next(sg); 93 } 94 95 sg_set_page(sg, iv.bv_page, iv.bv_len, iv.bv_offset); 96 segments++; 97 } 98 99 prev = 1; 100 ivprv = iv; 101 } 102 103 if (sg) 104 sg_mark_end(sg); 105 106 /* 107 * Something must have been wrong if the figured number of segment 108 * is bigger than number of req's physical integrity segments 109 */ 110 BUG_ON(segments > rq->nr_integrity_segments); 111 BUG_ON(segments > queue_max_integrity_segments(q)); 112 return segments; 113 } 114 EXPORT_SYMBOL(blk_rq_map_integrity_sg); 115 116 int blk_rq_integrity_map_user(struct request *rq, void __user *ubuf, 117 ssize_t bytes, u32 seed) 118 { 119 int ret = bio_integrity_map_user(rq->bio, ubuf, bytes, seed); 120 121 if (ret) 122 return ret; 123 124 rq->nr_integrity_segments = blk_rq_count_integrity_sg(rq->q, rq->bio); 125 rq->cmd_flags |= REQ_INTEGRITY; 126 return 0; 127 } 128 EXPORT_SYMBOL_GPL(blk_rq_integrity_map_user); 129 130 bool blk_integrity_merge_rq(struct request_queue *q, struct request *req, 131 struct request *next) 132 { 133 if (blk_integrity_rq(req) == 0 && blk_integrity_rq(next) == 0) 134 return true; 135 136 if (blk_integrity_rq(req) == 0 || blk_integrity_rq(next) == 0) 137 return false; 138 139 if (bio_integrity(req->bio)->bip_flags != 140 bio_integrity(next->bio)->bip_flags) 141 return false; 142 143 if (req->nr_integrity_segments + next->nr_integrity_segments > 144 q->limits.max_integrity_segments) 145 return false; 146 147 if (integrity_req_gap_back_merge(req, next->bio)) 148 return false; 149 150 return true; 151 } 152 153 bool blk_integrity_merge_bio(struct request_queue *q, struct request *req, 154 struct bio *bio) 155 { 156 int nr_integrity_segs; 157 158 if (blk_integrity_rq(req) == 0 && bio_integrity(bio) == NULL) 159 return true; 160 161 if (blk_integrity_rq(req) == 0 || bio_integrity(bio) == NULL) 162 return false; 163 164 if (bio_integrity(req->bio)->bip_flags != bio_integrity(bio)->bip_flags) 165 return false; 166 167 nr_integrity_segs = blk_rq_count_integrity_sg(q, bio); 168 if (req->nr_integrity_segments + nr_integrity_segs > 169 q->limits.max_integrity_segments) 170 return false; 171 172 return true; 173 } 174 175 static inline struct blk_integrity *dev_to_bi(struct device *dev) 176 { 177 return &dev_to_disk(dev)->queue->limits.integrity; 178 } 179 180 const char *blk_integrity_profile_name(struct blk_integrity *bi) 181 { 182 switch (bi->csum_type) { 183 case BLK_INTEGRITY_CSUM_IP: 184 if (bi->flags & BLK_INTEGRITY_REF_TAG) 185 return "T10-DIF-TYPE1-IP"; 186 return "T10-DIF-TYPE3-IP"; 187 case BLK_INTEGRITY_CSUM_CRC: 188 if (bi->flags & BLK_INTEGRITY_REF_TAG) 189 return "T10-DIF-TYPE1-CRC"; 190 return "T10-DIF-TYPE3-CRC"; 191 case BLK_INTEGRITY_CSUM_CRC64: 192 if (bi->flags & BLK_INTEGRITY_REF_TAG) 193 return "EXT-DIF-TYPE1-CRC64"; 194 return "EXT-DIF-TYPE3-CRC64"; 195 case BLK_INTEGRITY_CSUM_NONE: 196 break; 197 } 198 199 return "nop"; 200 } 201 EXPORT_SYMBOL_GPL(blk_integrity_profile_name); 202 203 static ssize_t flag_store(struct device *dev, const char *page, size_t count, 204 unsigned char flag) 205 { 206 struct request_queue *q = dev_to_disk(dev)->queue; 207 struct queue_limits lim; 208 unsigned long val; 209 int err; 210 211 err = kstrtoul(page, 10, &val); 212 if (err) 213 return err; 214 215 /* note that the flags are inverted vs the values in the sysfs files */ 216 lim = queue_limits_start_update(q); 217 if (val) 218 lim.integrity.flags &= ~flag; 219 else 220 lim.integrity.flags |= flag; 221 222 blk_mq_freeze_queue(q); 223 err = queue_limits_commit_update(q, &lim); 224 blk_mq_unfreeze_queue(q); 225 if (err) 226 return err; 227 return count; 228 } 229 230 static ssize_t flag_show(struct device *dev, char *page, unsigned char flag) 231 { 232 struct blk_integrity *bi = dev_to_bi(dev); 233 234 return sysfs_emit(page, "%d\n", !(bi->flags & flag)); 235 } 236 237 static ssize_t format_show(struct device *dev, struct device_attribute *attr, 238 char *page) 239 { 240 struct blk_integrity *bi = dev_to_bi(dev); 241 242 if (!bi->tuple_size) 243 return sysfs_emit(page, "none\n"); 244 return sysfs_emit(page, "%s\n", blk_integrity_profile_name(bi)); 245 } 246 247 static ssize_t tag_size_show(struct device *dev, struct device_attribute *attr, 248 char *page) 249 { 250 struct blk_integrity *bi = dev_to_bi(dev); 251 252 return sysfs_emit(page, "%u\n", bi->tag_size); 253 } 254 255 static ssize_t protection_interval_bytes_show(struct device *dev, 256 struct device_attribute *attr, 257 char *page) 258 { 259 struct blk_integrity *bi = dev_to_bi(dev); 260 261 return sysfs_emit(page, "%u\n", 262 bi->interval_exp ? 1 << bi->interval_exp : 0); 263 } 264 265 static ssize_t read_verify_store(struct device *dev, 266 struct device_attribute *attr, 267 const char *page, size_t count) 268 { 269 return flag_store(dev, page, count, BLK_INTEGRITY_NOVERIFY); 270 } 271 272 static ssize_t read_verify_show(struct device *dev, 273 struct device_attribute *attr, char *page) 274 { 275 return flag_show(dev, page, BLK_INTEGRITY_NOVERIFY); 276 } 277 278 static ssize_t write_generate_store(struct device *dev, 279 struct device_attribute *attr, 280 const char *page, size_t count) 281 { 282 return flag_store(dev, page, count, BLK_INTEGRITY_NOGENERATE); 283 } 284 285 static ssize_t write_generate_show(struct device *dev, 286 struct device_attribute *attr, char *page) 287 { 288 return flag_show(dev, page, BLK_INTEGRITY_NOGENERATE); 289 } 290 291 static ssize_t device_is_integrity_capable_show(struct device *dev, 292 struct device_attribute *attr, 293 char *page) 294 { 295 struct blk_integrity *bi = dev_to_bi(dev); 296 297 return sysfs_emit(page, "%u\n", 298 !!(bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE)); 299 } 300 301 static DEVICE_ATTR_RO(format); 302 static DEVICE_ATTR_RO(tag_size); 303 static DEVICE_ATTR_RO(protection_interval_bytes); 304 static DEVICE_ATTR_RW(read_verify); 305 static DEVICE_ATTR_RW(write_generate); 306 static DEVICE_ATTR_RO(device_is_integrity_capable); 307 308 static struct attribute *integrity_attrs[] = { 309 &dev_attr_format.attr, 310 &dev_attr_tag_size.attr, 311 &dev_attr_protection_interval_bytes.attr, 312 &dev_attr_read_verify.attr, 313 &dev_attr_write_generate.attr, 314 &dev_attr_device_is_integrity_capable.attr, 315 NULL 316 }; 317 318 const struct attribute_group blk_integrity_attr_group = { 319 .name = "integrity", 320 .attrs = integrity_attrs, 321 }; 322