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