1 /* 2 * Functions related to sysfs handling 3 */ 4 #include <linux/kernel.h> 5 #include <linux/module.h> 6 #include <linux/bio.h> 7 #include <linux/blkdev.h> 8 #include <linux/blktrace_api.h> 9 10 #include "blk.h" 11 12 struct queue_sysfs_entry { 13 struct attribute attr; 14 ssize_t (*show)(struct request_queue *, char *); 15 ssize_t (*store)(struct request_queue *, const char *, size_t); 16 }; 17 18 static ssize_t 19 queue_var_show(unsigned int var, char *page) 20 { 21 return sprintf(page, "%d\n", var); 22 } 23 24 static ssize_t 25 queue_var_store(unsigned long *var, const char *page, size_t count) 26 { 27 char *p = (char *) page; 28 29 *var = simple_strtoul(p, &p, 10); 30 return count; 31 } 32 33 static ssize_t queue_requests_show(struct request_queue *q, char *page) 34 { 35 return queue_var_show(q->nr_requests, (page)); 36 } 37 38 static ssize_t 39 queue_requests_store(struct request_queue *q, const char *page, size_t count) 40 { 41 struct request_list *rl = &q->rq; 42 unsigned long nr; 43 int ret = queue_var_store(&nr, page, count); 44 if (nr < BLKDEV_MIN_RQ) 45 nr = BLKDEV_MIN_RQ; 46 47 spin_lock_irq(q->queue_lock); 48 q->nr_requests = nr; 49 blk_queue_congestion_threshold(q); 50 51 if (rl->count[READ] >= queue_congestion_on_threshold(q)) 52 blk_set_queue_congested(q, READ); 53 else if (rl->count[READ] < queue_congestion_off_threshold(q)) 54 blk_clear_queue_congested(q, READ); 55 56 if (rl->count[WRITE] >= queue_congestion_on_threshold(q)) 57 blk_set_queue_congested(q, WRITE); 58 else if (rl->count[WRITE] < queue_congestion_off_threshold(q)) 59 blk_clear_queue_congested(q, WRITE); 60 61 if (rl->count[READ] >= q->nr_requests) { 62 blk_set_queue_full(q, READ); 63 } else if (rl->count[READ]+1 <= q->nr_requests) { 64 blk_clear_queue_full(q, READ); 65 wake_up(&rl->wait[READ]); 66 } 67 68 if (rl->count[WRITE] >= q->nr_requests) { 69 blk_set_queue_full(q, WRITE); 70 } else if (rl->count[WRITE]+1 <= q->nr_requests) { 71 blk_clear_queue_full(q, WRITE); 72 wake_up(&rl->wait[WRITE]); 73 } 74 spin_unlock_irq(q->queue_lock); 75 return ret; 76 } 77 78 static ssize_t queue_ra_show(struct request_queue *q, char *page) 79 { 80 int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10); 81 82 return queue_var_show(ra_kb, (page)); 83 } 84 85 static ssize_t 86 queue_ra_store(struct request_queue *q, const char *page, size_t count) 87 { 88 unsigned long ra_kb; 89 ssize_t ret = queue_var_store(&ra_kb, page, count); 90 91 q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10); 92 93 return ret; 94 } 95 96 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page) 97 { 98 int max_sectors_kb = q->max_sectors >> 1; 99 100 return queue_var_show(max_sectors_kb, (page)); 101 } 102 103 static ssize_t queue_hw_sector_size_show(struct request_queue *q, char *page) 104 { 105 return queue_var_show(q->hardsect_size, page); 106 } 107 108 static ssize_t 109 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) 110 { 111 unsigned long max_sectors_kb, 112 max_hw_sectors_kb = q->max_hw_sectors >> 1, 113 page_kb = 1 << (PAGE_CACHE_SHIFT - 10); 114 ssize_t ret = queue_var_store(&max_sectors_kb, page, count); 115 116 if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb) 117 return -EINVAL; 118 119 spin_lock_irq(q->queue_lock); 120 q->max_sectors = max_sectors_kb << 1; 121 spin_unlock_irq(q->queue_lock); 122 123 return ret; 124 } 125 126 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page) 127 { 128 int max_hw_sectors_kb = q->max_hw_sectors >> 1; 129 130 return queue_var_show(max_hw_sectors_kb, (page)); 131 } 132 133 static ssize_t queue_nonrot_show(struct request_queue *q, char *page) 134 { 135 return queue_var_show(!blk_queue_nonrot(q), page); 136 } 137 138 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page, 139 size_t count) 140 { 141 unsigned long nm; 142 ssize_t ret = queue_var_store(&nm, page, count); 143 144 spin_lock_irq(q->queue_lock); 145 if (nm) 146 queue_flag_clear(QUEUE_FLAG_NONROT, q); 147 else 148 queue_flag_set(QUEUE_FLAG_NONROT, q); 149 spin_unlock_irq(q->queue_lock); 150 151 return ret; 152 } 153 154 static ssize_t queue_nomerges_show(struct request_queue *q, char *page) 155 { 156 return queue_var_show(blk_queue_nomerges(q), page); 157 } 158 159 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page, 160 size_t count) 161 { 162 unsigned long nm; 163 ssize_t ret = queue_var_store(&nm, page, count); 164 165 spin_lock_irq(q->queue_lock); 166 if (nm) 167 queue_flag_set(QUEUE_FLAG_NOMERGES, q); 168 else 169 queue_flag_clear(QUEUE_FLAG_NOMERGES, q); 170 spin_unlock_irq(q->queue_lock); 171 172 return ret; 173 } 174 175 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page) 176 { 177 unsigned int set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags); 178 179 return queue_var_show(set != 0, page); 180 } 181 182 static ssize_t 183 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count) 184 { 185 ssize_t ret = -EINVAL; 186 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS) 187 unsigned long val; 188 189 ret = queue_var_store(&val, page, count); 190 spin_lock_irq(q->queue_lock); 191 if (val) 192 queue_flag_set(QUEUE_FLAG_SAME_COMP, q); 193 else 194 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q); 195 spin_unlock_irq(q->queue_lock); 196 #endif 197 return ret; 198 } 199 200 static ssize_t queue_iostats_show(struct request_queue *q, char *page) 201 { 202 return queue_var_show(blk_queue_io_stat(q), page); 203 } 204 205 static ssize_t queue_iostats_store(struct request_queue *q, const char *page, 206 size_t count) 207 { 208 unsigned long stats; 209 ssize_t ret = queue_var_store(&stats, page, count); 210 211 spin_lock_irq(q->queue_lock); 212 if (stats) 213 queue_flag_set(QUEUE_FLAG_IO_STAT, q); 214 else 215 queue_flag_clear(QUEUE_FLAG_IO_STAT, q); 216 spin_unlock_irq(q->queue_lock); 217 218 return ret; 219 } 220 221 static struct queue_sysfs_entry queue_requests_entry = { 222 .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR }, 223 .show = queue_requests_show, 224 .store = queue_requests_store, 225 }; 226 227 static struct queue_sysfs_entry queue_ra_entry = { 228 .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR }, 229 .show = queue_ra_show, 230 .store = queue_ra_store, 231 }; 232 233 static struct queue_sysfs_entry queue_max_sectors_entry = { 234 .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR }, 235 .show = queue_max_sectors_show, 236 .store = queue_max_sectors_store, 237 }; 238 239 static struct queue_sysfs_entry queue_max_hw_sectors_entry = { 240 .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO }, 241 .show = queue_max_hw_sectors_show, 242 }; 243 244 static struct queue_sysfs_entry queue_iosched_entry = { 245 .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR }, 246 .show = elv_iosched_show, 247 .store = elv_iosched_store, 248 }; 249 250 static struct queue_sysfs_entry queue_hw_sector_size_entry = { 251 .attr = {.name = "hw_sector_size", .mode = S_IRUGO }, 252 .show = queue_hw_sector_size_show, 253 }; 254 255 static struct queue_sysfs_entry queue_nonrot_entry = { 256 .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR }, 257 .show = queue_nonrot_show, 258 .store = queue_nonrot_store, 259 }; 260 261 static struct queue_sysfs_entry queue_nomerges_entry = { 262 .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR }, 263 .show = queue_nomerges_show, 264 .store = queue_nomerges_store, 265 }; 266 267 static struct queue_sysfs_entry queue_rq_affinity_entry = { 268 .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR }, 269 .show = queue_rq_affinity_show, 270 .store = queue_rq_affinity_store, 271 }; 272 273 static struct queue_sysfs_entry queue_iostats_entry = { 274 .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR }, 275 .show = queue_iostats_show, 276 .store = queue_iostats_store, 277 }; 278 279 static struct attribute *default_attrs[] = { 280 &queue_requests_entry.attr, 281 &queue_ra_entry.attr, 282 &queue_max_hw_sectors_entry.attr, 283 &queue_max_sectors_entry.attr, 284 &queue_iosched_entry.attr, 285 &queue_hw_sector_size_entry.attr, 286 &queue_nonrot_entry.attr, 287 &queue_nomerges_entry.attr, 288 &queue_rq_affinity_entry.attr, 289 &queue_iostats_entry.attr, 290 NULL, 291 }; 292 293 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr) 294 295 static ssize_t 296 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page) 297 { 298 struct queue_sysfs_entry *entry = to_queue(attr); 299 struct request_queue *q = 300 container_of(kobj, struct request_queue, kobj); 301 ssize_t res; 302 303 if (!entry->show) 304 return -EIO; 305 mutex_lock(&q->sysfs_lock); 306 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) { 307 mutex_unlock(&q->sysfs_lock); 308 return -ENOENT; 309 } 310 res = entry->show(q, page); 311 mutex_unlock(&q->sysfs_lock); 312 return res; 313 } 314 315 static ssize_t 316 queue_attr_store(struct kobject *kobj, struct attribute *attr, 317 const char *page, size_t length) 318 { 319 struct queue_sysfs_entry *entry = to_queue(attr); 320 struct request_queue *q; 321 ssize_t res; 322 323 if (!entry->store) 324 return -EIO; 325 326 q = container_of(kobj, struct request_queue, kobj); 327 mutex_lock(&q->sysfs_lock); 328 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) { 329 mutex_unlock(&q->sysfs_lock); 330 return -ENOENT; 331 } 332 res = entry->store(q, page, length); 333 mutex_unlock(&q->sysfs_lock); 334 return res; 335 } 336 337 /** 338 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed 339 * @kobj: the kobj belonging of the request queue to be released 340 * 341 * Description: 342 * blk_cleanup_queue is the pair to blk_init_queue() or 343 * blk_queue_make_request(). It should be called when a request queue is 344 * being released; typically when a block device is being de-registered. 345 * Currently, its primary task it to free all the &struct request 346 * structures that were allocated to the queue and the queue itself. 347 * 348 * Caveat: 349 * Hopefully the low level driver will have finished any 350 * outstanding requests first... 351 **/ 352 static void blk_release_queue(struct kobject *kobj) 353 { 354 struct request_queue *q = 355 container_of(kobj, struct request_queue, kobj); 356 struct request_list *rl = &q->rq; 357 358 blk_sync_queue(q); 359 360 if (rl->rq_pool) 361 mempool_destroy(rl->rq_pool); 362 363 if (q->queue_tags) 364 __blk_queue_free_tags(q); 365 366 blk_trace_shutdown(q); 367 368 bdi_destroy(&q->backing_dev_info); 369 kmem_cache_free(blk_requestq_cachep, q); 370 } 371 372 static struct sysfs_ops queue_sysfs_ops = { 373 .show = queue_attr_show, 374 .store = queue_attr_store, 375 }; 376 377 struct kobj_type blk_queue_ktype = { 378 .sysfs_ops = &queue_sysfs_ops, 379 .default_attrs = default_attrs, 380 .release = blk_release_queue, 381 }; 382 383 int blk_register_queue(struct gendisk *disk) 384 { 385 int ret; 386 387 struct request_queue *q = disk->queue; 388 389 if (WARN_ON(!q)) 390 return -ENXIO; 391 392 if (!q->request_fn) 393 return 0; 394 395 ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj), 396 "%s", "queue"); 397 if (ret < 0) 398 return ret; 399 400 kobject_uevent(&q->kobj, KOBJ_ADD); 401 402 ret = elv_register_queue(q); 403 if (ret) { 404 kobject_uevent(&q->kobj, KOBJ_REMOVE); 405 kobject_del(&q->kobj); 406 return ret; 407 } 408 409 return 0; 410 } 411 412 void blk_unregister_queue(struct gendisk *disk) 413 { 414 struct request_queue *q = disk->queue; 415 416 if (WARN_ON(!q)) 417 return; 418 419 if (q->request_fn) { 420 elv_unregister_queue(q); 421 422 kobject_uevent(&q->kobj, KOBJ_REMOVE); 423 kobject_del(&q->kobj); 424 kobject_put(&disk_to_dev(disk)->kobj); 425 } 426 } 427