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 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 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); 319