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 &q->kobj, "%s", "independent_access_ranges"); 127 if (ret) { 128 disk->ia_ranges = NULL; 129 kobject_put(&iars->kobj); 130 return ret; 131 } 132 133 for (i = 0; i < iars->nr_ia_ranges; i++) { 134 ret = kobject_init_and_add(&iars->ia_range[i].kobj, 135 &blk_ia_range_ktype, &iars->kobj, 136 "%d", i); 137 if (ret) { 138 while (--i >= 0) 139 kobject_del(&iars->ia_range[i].kobj); 140 kobject_del(&iars->kobj); 141 kobject_put(&iars->kobj); 142 return ret; 143 } 144 } 145 146 iars->sysfs_registered = true; 147 148 return 0; 149 } 150 151 void disk_unregister_independent_access_ranges(struct gendisk *disk) 152 { 153 struct request_queue *q = disk->queue; 154 struct blk_independent_access_ranges *iars = disk->ia_ranges; 155 int i; 156 157 lockdep_assert_held(&q->sysfs_dir_lock); 158 lockdep_assert_held(&q->sysfs_lock); 159 160 if (!iars) 161 return; 162 163 if (iars->sysfs_registered) { 164 for (i = 0; i < iars->nr_ia_ranges; i++) 165 kobject_del(&iars->ia_range[i].kobj); 166 kobject_del(&iars->kobj); 167 kobject_put(&iars->kobj); 168 } else { 169 kfree(iars); 170 } 171 172 disk->ia_ranges = NULL; 173 } 174 175 static struct blk_independent_access_range * 176 disk_find_ia_range(struct blk_independent_access_ranges *iars, 177 sector_t sector) 178 { 179 struct blk_independent_access_range *iar; 180 int i; 181 182 for (i = 0; i < iars->nr_ia_ranges; i++) { 183 iar = &iars->ia_range[i]; 184 if (sector >= iar->sector && 185 sector < iar->sector + iar->nr_sectors) 186 return iar; 187 } 188 189 return NULL; 190 } 191 192 static bool disk_check_ia_ranges(struct gendisk *disk, 193 struct blk_independent_access_ranges *iars) 194 { 195 struct blk_independent_access_range *iar, *tmp; 196 sector_t capacity = get_capacity(disk); 197 sector_t sector = 0; 198 int i; 199 200 if (WARN_ON_ONCE(!iars->nr_ia_ranges)) 201 return false; 202 203 /* 204 * While sorting the ranges in increasing LBA order, check that the 205 * ranges do not overlap, that there are no sector holes and that all 206 * sectors belong to one range. 207 */ 208 for (i = 0; i < iars->nr_ia_ranges; i++) { 209 tmp = disk_find_ia_range(iars, sector); 210 if (!tmp || tmp->sector != sector) { 211 pr_warn("Invalid non-contiguous independent access ranges\n"); 212 return false; 213 } 214 215 iar = &iars->ia_range[i]; 216 if (tmp != iar) { 217 swap(iar->sector, tmp->sector); 218 swap(iar->nr_sectors, tmp->nr_sectors); 219 } 220 221 sector += iar->nr_sectors; 222 } 223 224 if (sector != capacity) { 225 pr_warn("Independent access ranges do not match disk capacity\n"); 226 return false; 227 } 228 229 return true; 230 } 231 232 static bool disk_ia_ranges_changed(struct gendisk *disk, 233 struct blk_independent_access_ranges *new) 234 { 235 struct blk_independent_access_ranges *old = disk->ia_ranges; 236 int i; 237 238 if (!old) 239 return true; 240 241 if (old->nr_ia_ranges != new->nr_ia_ranges) 242 return true; 243 244 for (i = 0; i < old->nr_ia_ranges; i++) { 245 if (new->ia_range[i].sector != old->ia_range[i].sector || 246 new->ia_range[i].nr_sectors != old->ia_range[i].nr_sectors) 247 return true; 248 } 249 250 return false; 251 } 252 253 /** 254 * disk_alloc_independent_access_ranges - Allocate an independent access ranges 255 * data structure 256 * @disk: target disk 257 * @nr_ia_ranges: Number of independent access ranges 258 * 259 * Allocate a struct blk_independent_access_ranges structure with @nr_ia_ranges 260 * access range descriptors. 261 */ 262 struct blk_independent_access_ranges * 263 disk_alloc_independent_access_ranges(struct gendisk *disk, int nr_ia_ranges) 264 { 265 struct blk_independent_access_ranges *iars; 266 267 iars = kzalloc_node(struct_size(iars, ia_range, nr_ia_ranges), 268 GFP_KERNEL, disk->queue->node); 269 if (iars) 270 iars->nr_ia_ranges = nr_ia_ranges; 271 return iars; 272 } 273 EXPORT_SYMBOL_GPL(disk_alloc_independent_access_ranges); 274 275 /** 276 * disk_set_independent_access_ranges - Set a disk independent access ranges 277 * @disk: target disk 278 * @iars: independent access ranges structure 279 * 280 * Set the independent access ranges information of the request queue 281 * of @disk to @iars. If @iars is NULL and the independent access ranges 282 * structure already set is cleared. If there are no differences between 283 * @iars and the independent access ranges structure already set, @iars 284 * is freed. 285 */ 286 void disk_set_independent_access_ranges(struct gendisk *disk, 287 struct blk_independent_access_ranges *iars) 288 { 289 struct request_queue *q = disk->queue; 290 291 mutex_lock(&q->sysfs_dir_lock); 292 mutex_lock(&q->sysfs_lock); 293 if (iars && !disk_check_ia_ranges(disk, iars)) { 294 kfree(iars); 295 iars = NULL; 296 } 297 if (iars && !disk_ia_ranges_changed(disk, iars)) { 298 kfree(iars); 299 goto unlock; 300 } 301 302 /* 303 * This may be called for a registered queue. E.g. during a device 304 * revalidation. If that is the case, we need to unregister the old 305 * set of independent access ranges and register the new set. If the 306 * queue is not registered, registration of the device request queue 307 * will register the independent access ranges. 308 */ 309 disk_unregister_independent_access_ranges(disk); 310 disk->ia_ranges = iars; 311 if (blk_queue_registered(q)) 312 disk_register_independent_access_ranges(disk); 313 unlock: 314 mutex_unlock(&q->sysfs_lock); 315 mutex_unlock(&q->sysfs_dir_lock); 316 } 317 EXPORT_SYMBOL_GPL(disk_set_independent_access_ranges); 318