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