| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * Block device concurrent positioning ranges. |
| 4 | * |
| 5 | * Copyright (C) 2021 Western Digital Corporation or its Affiliates. |
| 6 | */ |
| 7 | #include <linux/kernel.h> |
| 8 | #include <linux/blkdev.h> |
| 9 | #include <linux/slab.h> |
| 10 | #include <linux/init.h> |
| 11 | |
| 12 | #include "blk.h" |
| 13 | |
| 14 | static ssize_t |
| 15 | blk_ia_range_sector_show(struct blk_independent_access_range *iar, |
| 16 | char *buf) |
| 17 | { |
| 18 | return sprintf(buf, "%llu\n", iar->sector); |
| 19 | } |
| 20 | |
| 21 | static ssize_t |
| 22 | blk_ia_range_nr_sectors_show(struct blk_independent_access_range *iar, |
| 23 | char *buf) |
| 24 | { |
| 25 | return sprintf(buf, "%llu\n", iar->nr_sectors); |
| 26 | } |
| 27 | |
| 28 | struct blk_ia_range_sysfs_entry { |
| 29 | struct attribute attr; |
| 30 | ssize_t (*show)(struct blk_independent_access_range *iar, char *buf); |
| 31 | }; |
| 32 | |
| 33 | static struct blk_ia_range_sysfs_entry blk_ia_range_sector_entry = { |
| 34 | .attr = { .name = "sector", .mode = 0444 }, |
| 35 | .show = blk_ia_range_sector_show, |
| 36 | }; |
| 37 | |
| 38 | static struct blk_ia_range_sysfs_entry blk_ia_range_nr_sectors_entry = { |
| 39 | .attr = { .name = "nr_sectors", .mode = 0444 }, |
| 40 | .show = blk_ia_range_nr_sectors_show, |
| 41 | }; |
| 42 | |
| 43 | static struct attribute *blk_ia_range_attrs[] = { |
| 44 | &blk_ia_range_sector_entry.attr, |
| 45 | &blk_ia_range_nr_sectors_entry.attr, |
| 46 | NULL, |
| 47 | }; |
| 48 | ATTRIBUTE_GROUPS(blk_ia_range); |
| 49 | |
| 50 | static ssize_t blk_ia_range_sysfs_show(struct kobject *kobj, |
| 51 | struct attribute *attr, char *buf) |
| 52 | { |
| 53 | struct blk_ia_range_sysfs_entry *entry = |
| 54 | container_of(attr, struct blk_ia_range_sysfs_entry, attr); |
| 55 | struct blk_independent_access_range *iar = |
| 56 | container_of(kobj, struct blk_independent_access_range, kobj); |
| 57 | |
| 58 | return entry->show(iar, buf); |
| 59 | } |
| 60 | |
| 61 | static const struct sysfs_ops blk_ia_range_sysfs_ops = { |
| 62 | .show = blk_ia_range_sysfs_show, |
| 63 | }; |
| 64 | |
| 65 | /* |
| 66 | * Independent access range entries are not freed individually, but alltogether |
| 67 | * with struct blk_independent_access_ranges and its array of ranges. Since |
| 68 | * kobject_add() takes a reference on the parent kobject contained in |
| 69 | * struct blk_independent_access_ranges, the array of independent access range |
| 70 | * entries cannot be freed until kobject_del() is called for all entries. |
| 71 | * So we do not need to do anything here, but still need this no-op release |
| 72 | * operation to avoid complaints from the kobject code. |
| 73 | */ |
| 74 | static void blk_ia_range_sysfs_nop_release(struct kobject *kobj) |
| 75 | { |
| 76 | } |
| 77 | |
| 78 | static const struct kobj_type blk_ia_range_ktype = { |
| 79 | .sysfs_ops = &blk_ia_range_sysfs_ops, |
| 80 | .default_groups = blk_ia_range_groups, |
| 81 | .release = blk_ia_range_sysfs_nop_release, |
| 82 | }; |
| 83 | |
| 84 | /* |
| 85 | * This will be executed only after all independent access range entries are |
| 86 | * removed with kobject_del(), at which point, it is safe to free everything, |
| 87 | * including the array of ranges. |
| 88 | */ |
| 89 | static void blk_ia_ranges_sysfs_release(struct kobject *kobj) |
| 90 | { |
| 91 | struct blk_independent_access_ranges *iars = |
| 92 | container_of(kobj, struct blk_independent_access_ranges, kobj); |
| 93 | |
| 94 | kfree(iars); |
| 95 | } |
| 96 | |
| 97 | static const struct kobj_type blk_ia_ranges_ktype = { |
| 98 | .release = blk_ia_ranges_sysfs_release, |
| 99 | }; |
| 100 | |
| 101 | /** |
| 102 | * disk_register_independent_access_ranges - register with sysfs a set of |
| 103 | * independent access ranges |
| 104 | * @disk: Target disk |
| 105 | * |
| 106 | * Register with sysfs a set of independent access ranges for @disk. |
| 107 | */ |
| 108 | int disk_register_independent_access_ranges(struct gendisk *disk) |
| 109 | { |
| 110 | struct blk_independent_access_ranges *iars = disk->ia_ranges; |
| 111 | struct request_queue *q = disk->queue; |
| 112 | int i, ret; |
| 113 | |
| 114 | lockdep_assert_held(&q->sysfs_dir_lock); |
| 115 | lockdep_assert_held(&q->sysfs_lock); |
| 116 | |
| 117 | if (!iars) |
| 118 | return 0; |
| 119 | |
| 120 | /* |
| 121 | * At this point, iars is the new set of sector access ranges that needs |
| 122 | * to be registered with sysfs. |
| 123 | */ |
| 124 | WARN_ON(iars->sysfs_registered); |
| 125 | ret = kobject_init_and_add(&iars->kobj, &blk_ia_ranges_ktype, |
| 126 | &disk->queue_kobj, "%s", |
| 127 | "independent_access_ranges"); |
| 128 | if (ret) { |
| 129 | disk->ia_ranges = NULL; |
| 130 | kobject_put(&iars->kobj); |
| 131 | return ret; |
| 132 | } |
| 133 | |
| 134 | for (i = 0; i < iars->nr_ia_ranges; i++) { |
| 135 | ret = kobject_init_and_add(&iars->ia_range[i].kobj, |
| 136 | &blk_ia_range_ktype, &iars->kobj, |
| 137 | "%d", i); |
| 138 | if (ret) { |
| 139 | while (--i >= 0) |
| 140 | kobject_del(&iars->ia_range[i].kobj); |
| 141 | kobject_del(&iars->kobj); |
| 142 | kobject_put(&iars->kobj); |
| 143 | return ret; |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | iars->sysfs_registered = true; |
| 148 | |
| 149 | return 0; |
| 150 | } |
| 151 | |
| 152 | void disk_unregister_independent_access_ranges(struct gendisk *disk) |
| 153 | { |
| 154 | struct request_queue *q = disk->queue; |
| 155 | struct blk_independent_access_ranges *iars = disk->ia_ranges; |
| 156 | int i; |
| 157 | |
| 158 | lockdep_assert_held(&q->sysfs_dir_lock); |
| 159 | lockdep_assert_held(&q->sysfs_lock); |
| 160 | |
| 161 | if (!iars) |
| 162 | return; |
| 163 | |
| 164 | if (iars->sysfs_registered) { |
| 165 | for (i = 0; i < iars->nr_ia_ranges; i++) |
| 166 | kobject_del(&iars->ia_range[i].kobj); |
| 167 | kobject_del(&iars->kobj); |
| 168 | kobject_put(&iars->kobj); |
| 169 | } else { |
| 170 | kfree(iars); |
| 171 | } |
| 172 | |
| 173 | disk->ia_ranges = NULL; |
| 174 | } |
| 175 | |
| 176 | static struct blk_independent_access_range * |
| 177 | disk_find_ia_range(struct blk_independent_access_ranges *iars, |
| 178 | sector_t sector) |
| 179 | { |
| 180 | struct blk_independent_access_range *iar; |
| 181 | int i; |
| 182 | |
| 183 | for (i = 0; i < iars->nr_ia_ranges; i++) { |
| 184 | iar = &iars->ia_range[i]; |
| 185 | if (sector >= iar->sector && |
| 186 | sector < iar->sector + iar->nr_sectors) |
| 187 | return iar; |
| 188 | } |
| 189 | |
| 190 | return NULL; |
| 191 | } |
| 192 | |
| 193 | static bool disk_check_ia_ranges(struct gendisk *disk, |
| 194 | struct blk_independent_access_ranges *iars) |
| 195 | { |
| 196 | struct blk_independent_access_range *iar, *tmp; |
| 197 | sector_t capacity = get_capacity(disk); |
| 198 | sector_t sector = 0; |
| 199 | int i; |
| 200 | |
| 201 | if (WARN_ON_ONCE(!iars->nr_ia_ranges)) |
| 202 | return false; |
| 203 | |
| 204 | /* |
| 205 | * While sorting the ranges in increasing LBA order, check that the |
| 206 | * ranges do not overlap, that there are no sector holes and that all |
| 207 | * sectors belong to one range. |
| 208 | */ |
| 209 | for (i = 0; i < iars->nr_ia_ranges; i++) { |
| 210 | tmp = disk_find_ia_range(iars, sector); |
| 211 | if (!tmp || tmp->sector != sector) { |
| 212 | pr_warn("Invalid non-contiguous independent access ranges\n"); |
| 213 | return false; |
| 214 | } |
| 215 | |
| 216 | iar = &iars->ia_range[i]; |
| 217 | if (tmp != iar) { |
| 218 | swap(iar->sector, tmp->sector); |
| 219 | swap(iar->nr_sectors, tmp->nr_sectors); |
| 220 | } |
| 221 | |
| 222 | sector += iar->nr_sectors; |
| 223 | } |
| 224 | |
| 225 | if (sector != capacity) { |
| 226 | pr_warn("Independent access ranges do not match disk capacity\n"); |
| 227 | return false; |
| 228 | } |
| 229 | |
| 230 | return true; |
| 231 | } |
| 232 | |
| 233 | static bool disk_ia_ranges_changed(struct gendisk *disk, |
| 234 | struct blk_independent_access_ranges *new) |
| 235 | { |
| 236 | struct blk_independent_access_ranges *old = disk->ia_ranges; |
| 237 | int i; |
| 238 | |
| 239 | if (!old) |
| 240 | return true; |
| 241 | |
| 242 | if (old->nr_ia_ranges != new->nr_ia_ranges) |
| 243 | return true; |
| 244 | |
| 245 | for (i = 0; i < old->nr_ia_ranges; i++) { |
| 246 | if (new->ia_range[i].sector != old->ia_range[i].sector || |
| 247 | new->ia_range[i].nr_sectors != old->ia_range[i].nr_sectors) |
| 248 | return true; |
| 249 | } |
| 250 | |
| 251 | return false; |
| 252 | } |
| 253 | |
| 254 | /** |
| 255 | * disk_alloc_independent_access_ranges - Allocate an independent access ranges |
| 256 | * data structure |
| 257 | * @disk: target disk |
| 258 | * @nr_ia_ranges: Number of independent access ranges |
| 259 | * |
| 260 | * Allocate a struct blk_independent_access_ranges structure with @nr_ia_ranges |
| 261 | * access range descriptors. |
| 262 | */ |
| 263 | struct blk_independent_access_ranges * |
| 264 | disk_alloc_independent_access_ranges(struct gendisk *disk, int nr_ia_ranges) |
| 265 | { |
| 266 | struct blk_independent_access_ranges *iars; |
| 267 | |
| 268 | iars = kzalloc_node(struct_size(iars, ia_range, nr_ia_ranges), |
| 269 | GFP_KERNEL, disk->queue->node); |
| 270 | if (iars) |
| 271 | iars->nr_ia_ranges = nr_ia_ranges; |
| 272 | return iars; |
| 273 | } |
| 274 | EXPORT_SYMBOL_GPL(disk_alloc_independent_access_ranges); |
| 275 | |
| 276 | /** |
| 277 | * disk_set_independent_access_ranges - Set a disk independent access ranges |
| 278 | * @disk: target disk |
| 279 | * @iars: independent access ranges structure |
| 280 | * |
| 281 | * Set the independent access ranges information of the request queue |
| 282 | * of @disk to @iars. If @iars is NULL and the independent access ranges |
| 283 | * structure already set is cleared. If there are no differences between |
| 284 | * @iars and the independent access ranges structure already set, @iars |
| 285 | * is freed. |
| 286 | */ |
| 287 | void disk_set_independent_access_ranges(struct gendisk *disk, |
| 288 | struct blk_independent_access_ranges *iars) |
| 289 | { |
| 290 | struct request_queue *q = disk->queue; |
| 291 | |
| 292 | mutex_lock(&q->sysfs_dir_lock); |
| 293 | mutex_lock(&q->sysfs_lock); |
| 294 | if (iars && !disk_check_ia_ranges(disk, iars)) { |
| 295 | kfree(iars); |
| 296 | iars = NULL; |
| 297 | } |
| 298 | if (iars && !disk_ia_ranges_changed(disk, iars)) { |
| 299 | kfree(iars); |
| 300 | goto unlock; |
| 301 | } |
| 302 | |
| 303 | /* |
| 304 | * This may be called for a registered queue. E.g. during a device |
| 305 | * revalidation. If that is the case, we need to unregister the old |
| 306 | * set of independent access ranges and register the new set. If the |
| 307 | * queue is not registered, registration of the device request queue |
| 308 | * will register the independent access ranges. |
| 309 | */ |
| 310 | disk_unregister_independent_access_ranges(disk); |
| 311 | disk->ia_ranges = iars; |
| 312 | if (blk_queue_registered(q)) |
| 313 | disk_register_independent_access_ranges(disk); |
| 314 | unlock: |
| 315 | mutex_unlock(&q->sysfs_lock); |
| 316 | mutex_unlock(&q->sysfs_dir_lock); |
| 317 | } |
| 318 | EXPORT_SYMBOL_GPL(disk_set_independent_access_ranges); |