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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 spin_lock_irq(q->queue_lock); 92 q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10); 93 spin_unlock_irq(q->queue_lock); 94 95 return ret; 96 } 97 98 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page) 99 { 100 int max_sectors_kb = q->max_sectors >> 1; 101 102 return queue_var_show(max_sectors_kb, (page)); 103 } 104 105 static ssize_t queue_hw_sector_size_show(struct request_queue *q, char *page) 106 { 107 return queue_var_show(q->hardsect_size, page); 108 } 109 110 static ssize_t 111 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) 112 { 113 unsigned long max_sectors_kb, 114 max_hw_sectors_kb = q->max_hw_sectors >> 1, 115 page_kb = 1 << (PAGE_CACHE_SHIFT - 10); 116 ssize_t ret = queue_var_store(&max_sectors_kb, page, count); 117 118 if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb) 119 return -EINVAL; 120 /* 121 * Take the queue lock to update the readahead and max_sectors 122 * values synchronously: 123 */ 124 spin_lock_irq(q->queue_lock); 125 q->max_sectors = max_sectors_kb << 1; 126 spin_unlock_irq(q->queue_lock); 127 128 return ret; 129 } 130 131 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page) 132 { 133 int max_hw_sectors_kb = q->max_hw_sectors >> 1; 134 135 return queue_var_show(max_hw_sectors_kb, (page)); 136 } 137 138 static ssize_t queue_nomerges_show(struct request_queue *q, char *page) 139 { 140 return queue_var_show(blk_queue_nomerges(q), page); 141 } 142 143 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page, 144 size_t count) 145 { 146 unsigned long nm; 147 ssize_t ret = queue_var_store(&nm, page, count); 148 149 spin_lock_irq(q->queue_lock); 150 if (nm) 151 queue_flag_set(QUEUE_FLAG_NOMERGES, q); 152 else 153 queue_flag_clear(QUEUE_FLAG_NOMERGES, q); 154 155 spin_unlock_irq(q->queue_lock); 156 return ret; 157 } 158 159 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page) 160 { 161 unsigned int set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags); 162 163 return queue_var_show(set != 0, page); 164 } 165 166 static ssize_t 167 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count) 168 { 169 ssize_t ret = -EINVAL; 170 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS) 171 unsigned long val; 172 173 ret = queue_var_store(&val, page, count); 174 spin_lock_irq(q->queue_lock); 175 if (val) 176 queue_flag_set(QUEUE_FLAG_SAME_COMP, q); 177 else 178 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q); 179 spin_unlock_irq(q->queue_lock); 180 #endif 181 return ret; 182 } 183 184 static struct queue_sysfs_entry queue_requests_entry = { 185 .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR }, 186 .show = queue_requests_show, 187 .store = queue_requests_store, 188 }; 189 190 static struct queue_sysfs_entry queue_ra_entry = { 191 .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR }, 192 .show = queue_ra_show, 193 .store = queue_ra_store, 194 }; 195 196 static struct queue_sysfs_entry queue_max_sectors_entry = { 197 .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR }, 198 .show = queue_max_sectors_show, 199 .store = queue_max_sectors_store, 200 }; 201 202 static struct queue_sysfs_entry queue_max_hw_sectors_entry = { 203 .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO }, 204 .show = queue_max_hw_sectors_show, 205 }; 206 207 static struct queue_sysfs_entry queue_iosched_entry = { 208 .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR }, 209 .show = elv_iosched_show, 210 .store = elv_iosched_store, 211 }; 212 213 static struct queue_sysfs_entry queue_hw_sector_size_entry = { 214 .attr = {.name = "hw_sector_size", .mode = S_IRUGO }, 215 .show = queue_hw_sector_size_show, 216 }; 217 218 static struct queue_sysfs_entry queue_nomerges_entry = { 219 .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR }, 220 .show = queue_nomerges_show, 221 .store = queue_nomerges_store, 222 }; 223 224 static struct queue_sysfs_entry queue_rq_affinity_entry = { 225 .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR }, 226 .show = queue_rq_affinity_show, 227 .store = queue_rq_affinity_store, 228 }; 229 230 static struct attribute *default_attrs[] = { 231 &queue_requests_entry.attr, 232 &queue_ra_entry.attr, 233 &queue_max_hw_sectors_entry.attr, 234 &queue_max_sectors_entry.attr, 235 &queue_iosched_entry.attr, 236 &queue_hw_sector_size_entry.attr, 237 &queue_nomerges_entry.attr, 238 &queue_rq_affinity_entry.attr, 239 NULL, 240 }; 241 242 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr) 243 244 static ssize_t 245 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page) 246 { 247 struct queue_sysfs_entry *entry = to_queue(attr); 248 struct request_queue *q = 249 container_of(kobj, struct request_queue, kobj); 250 ssize_t res; 251 252 if (!entry->show) 253 return -EIO; 254 mutex_lock(&q->sysfs_lock); 255 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) { 256 mutex_unlock(&q->sysfs_lock); 257 return -ENOENT; 258 } 259 res = entry->show(q, page); 260 mutex_unlock(&q->sysfs_lock); 261 return res; 262 } 263 264 static ssize_t 265 queue_attr_store(struct kobject *kobj, struct attribute *attr, 266 const char *page, size_t length) 267 { 268 struct queue_sysfs_entry *entry = to_queue(attr); 269 struct request_queue *q; 270 ssize_t res; 271 272 if (!entry->store) 273 return -EIO; 274 275 q = container_of(kobj, struct request_queue, kobj); 276 mutex_lock(&q->sysfs_lock); 277 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) { 278 mutex_unlock(&q->sysfs_lock); 279 return -ENOENT; 280 } 281 res = entry->store(q, page, length); 282 mutex_unlock(&q->sysfs_lock); 283 return res; 284 } 285 286 /** 287 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed 288 * @kobj: the kobj belonging of the request queue to be released 289 * 290 * Description: 291 * blk_cleanup_queue is the pair to blk_init_queue() or 292 * blk_queue_make_request(). It should be called when a request queue is 293 * being released; typically when a block device is being de-registered. 294 * Currently, its primary task it to free all the &struct request 295 * structures that were allocated to the queue and the queue itself. 296 * 297 * Caveat: 298 * Hopefully the low level driver will have finished any 299 * outstanding requests first... 300 **/ 301 static void blk_release_queue(struct kobject *kobj) 302 { 303 struct request_queue *q = 304 container_of(kobj, struct request_queue, kobj); 305 struct request_list *rl = &q->rq; 306 307 blk_sync_queue(q); 308 309 if (rl->rq_pool) 310 mempool_destroy(rl->rq_pool); 311 312 if (q->queue_tags) 313 __blk_queue_free_tags(q); 314 315 blk_trace_shutdown(q); 316 317 bdi_destroy(&q->backing_dev_info); 318 kmem_cache_free(blk_requestq_cachep, q); 319 } 320 321 static struct sysfs_ops queue_sysfs_ops = { 322 .show = queue_attr_show, 323 .store = queue_attr_store, 324 }; 325 326 struct kobj_type blk_queue_ktype = { 327 .sysfs_ops = &queue_sysfs_ops, 328 .default_attrs = default_attrs, 329 .release = blk_release_queue, 330 }; 331 332 int blk_register_queue(struct gendisk *disk) 333 { 334 int ret; 335 336 struct request_queue *q = disk->queue; 337 338 if (WARN_ON(!q)) 339 return -ENXIO; 340 341 if (!q->request_fn) 342 return 0; 343 344 ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj), 345 "%s", "queue"); 346 if (ret < 0) 347 return ret; 348 349 kobject_uevent(&q->kobj, KOBJ_ADD); 350 351 ret = elv_register_queue(q); 352 if (ret) { 353 kobject_uevent(&q->kobj, KOBJ_REMOVE); 354 kobject_del(&q->kobj); 355 return ret; 356 } 357 358 return 0; 359 } 360 361 void blk_unregister_queue(struct gendisk *disk) 362 { 363 struct request_queue *q = disk->queue; 364 365 if (WARN_ON(!q)) 366 return; 367 368 if (q->request_fn) { 369 elv_unregister_queue(q); 370 371 kobject_uevent(&q->kobj, KOBJ_REMOVE); 372 kobject_del(&q->kobj); 373 kobject_put(&disk_to_dev(disk)->kobj); 374 } 375 } 376
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