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 } 137 138 139 static struct queue_sysfs_entry queue_requests_entry = { 140 .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR }, 141 .show = queue_requests_show, 142 .store = queue_requests_store, 143 }; 144 145 static struct queue_sysfs_entry queue_ra_entry = { 146 .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR }, 147 .show = queue_ra_show, 148 .store = queue_ra_store, 149 }; 150 151 static struct queue_sysfs_entry queue_max_sectors_entry = { 152 .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR }, 153 .show = queue_max_sectors_show, 154 .store = queue_max_sectors_store, 155 }; 156 157 static struct queue_sysfs_entry queue_max_hw_sectors_entry = { 158 .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO }, 159 .show = queue_max_hw_sectors_show, 160 }; 161 162 static struct queue_sysfs_entry queue_iosched_entry = { 163 .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR }, 164 .show = elv_iosched_show, 165 .store = elv_iosched_store, 166 }; 167 168 static struct queue_sysfs_entry queue_hw_sector_size_entry = { 169 .attr = {.name = "hw_sector_size", .mode = S_IRUGO }, 170 .show = queue_hw_sector_size_show, 171 }; 172 173 static struct attribute *default_attrs[] = { 174 &queue_requests_entry.attr, 175 &queue_ra_entry.attr, 176 &queue_max_hw_sectors_entry.attr, 177 &queue_max_sectors_entry.attr, 178 &queue_iosched_entry.attr, 179 &queue_hw_sector_size_entry.attr, 180 NULL, 181 }; 182 183 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr) 184 185 static ssize_t 186 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page) 187 { 188 struct queue_sysfs_entry *entry = to_queue(attr); 189 struct request_queue *q = 190 container_of(kobj, struct request_queue, kobj); 191 ssize_t res; 192 193 if (!entry->show) 194 return -EIO; 195 mutex_lock(&q->sysfs_lock); 196 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) { 197 mutex_unlock(&q->sysfs_lock); 198 return -ENOENT; 199 } 200 res = entry->show(q, page); 201 mutex_unlock(&q->sysfs_lock); 202 return res; 203 } 204 205 static ssize_t 206 queue_attr_store(struct kobject *kobj, struct attribute *attr, 207 const char *page, size_t length) 208 { 209 struct queue_sysfs_entry *entry = to_queue(attr); 210 struct request_queue *q; 211 ssize_t res; 212 213 if (!entry->store) 214 return -EIO; 215 216 q = container_of(kobj, struct request_queue, kobj); 217 mutex_lock(&q->sysfs_lock); 218 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) { 219 mutex_unlock(&q->sysfs_lock); 220 return -ENOENT; 221 } 222 res = entry->store(q, page, length); 223 mutex_unlock(&q->sysfs_lock); 224 return res; 225 } 226 227 /** 228 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed 229 * @kobj: the kobj belonging of the request queue to be released 230 * 231 * Description: 232 * blk_cleanup_queue is the pair to blk_init_queue() or 233 * blk_queue_make_request(). It should be called when a request queue is 234 * being released; typically when a block device is being de-registered. 235 * Currently, its primary task it to free all the &struct request 236 * structures that were allocated to the queue and the queue itself. 237 * 238 * Caveat: 239 * Hopefully the low level driver will have finished any 240 * outstanding requests first... 241 **/ 242 static void blk_release_queue(struct kobject *kobj) 243 { 244 struct request_queue *q = 245 container_of(kobj, struct request_queue, kobj); 246 struct request_list *rl = &q->rq; 247 248 blk_sync_queue(q); 249 250 if (rl->rq_pool) 251 mempool_destroy(rl->rq_pool); 252 253 if (q->queue_tags) 254 __blk_queue_free_tags(q); 255 256 blk_trace_shutdown(q); 257 258 bdi_destroy(&q->backing_dev_info); 259 kmem_cache_free(blk_requestq_cachep, q); 260 } 261 262 static struct sysfs_ops queue_sysfs_ops = { 263 .show = queue_attr_show, 264 .store = queue_attr_store, 265 }; 266 267 struct kobj_type blk_queue_ktype = { 268 .sysfs_ops = &queue_sysfs_ops, 269 .default_attrs = default_attrs, 270 .release = blk_release_queue, 271 }; 272 273 int blk_register_queue(struct gendisk *disk) 274 { 275 int ret; 276 277 struct request_queue *q = disk->queue; 278 279 if (!q || !q->request_fn) 280 return -ENXIO; 281 282 ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj), 283 "%s", "queue"); 284 if (ret < 0) 285 return ret; 286 287 kobject_uevent(&q->kobj, KOBJ_ADD); 288 289 ret = elv_register_queue(q); 290 if (ret) { 291 kobject_uevent(&q->kobj, KOBJ_REMOVE); 292 kobject_del(&q->kobj); 293 return ret; 294 } 295 296 return 0; 297 } 298 299 void blk_unregister_queue(struct gendisk *disk) 300 { 301 struct request_queue *q = disk->queue; 302 303 if (q && q->request_fn) { 304 elv_unregister_queue(q); 305 306 kobject_uevent(&q->kobj, KOBJ_REMOVE); 307 kobject_del(&q->kobj); 308 kobject_put(&disk->dev.kobj); 309 } 310 } 311