2 * Functions related to sysfs handling
4 #include <linux/kernel.h>
5 #include <linux/module.h>
7 #include <linux/blkdev.h>
8 #include <linux/blktrace_api.h>
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);
19 queue_var_show(unsigned int var, char *page)
21 return sprintf(page, "%d\n", var);
25 queue_var_store(unsigned long *var, const char *page, size_t count)
27 char *p = (char *) page;
29 *var = simple_strtoul(p, &p, 10);
33 static ssize_t queue_requests_show(struct request_queue *q, char *page)
35 return queue_var_show(q->nr_requests, (page));
39 queue_requests_store(struct request_queue *q, const char *page, size_t count)
41 struct request_list *rl = &q->rq;
43 int ret = queue_var_store(&nr, page, count);
44 if (nr < BLKDEV_MIN_RQ)
47 spin_lock_irq(q->queue_lock);
49 blk_queue_congestion_threshold(q);
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);
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);
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]);
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]);
74 spin_unlock_irq(q->queue_lock);
78 static ssize_t queue_ra_show(struct request_queue *q, char *page)
80 int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
82 return queue_var_show(ra_kb, (page));
86 queue_ra_store(struct request_queue *q, const char *page, size_t count)
89 ssize_t ret = queue_var_store(&ra_kb, page, count);
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);
98 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
100 int max_sectors_kb = q->max_sectors >> 1;
102 return queue_var_show(max_sectors_kb, (page));
106 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
108 unsigned long max_sectors_kb,
109 max_hw_sectors_kb = q->max_hw_sectors >> 1,
110 page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
111 ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
113 if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
116 * Take the queue lock to update the readahead and max_sectors
117 * values synchronously:
119 spin_lock_irq(q->queue_lock);
120 q->max_sectors = max_sectors_kb << 1;
121 spin_unlock_irq(q->queue_lock);
126 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
128 int max_hw_sectors_kb = q->max_hw_sectors >> 1;
130 return queue_var_show(max_hw_sectors_kb, (page));
134 static struct queue_sysfs_entry queue_requests_entry = {
135 .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
136 .show = queue_requests_show,
137 .store = queue_requests_store,
140 static struct queue_sysfs_entry queue_ra_entry = {
141 .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
142 .show = queue_ra_show,
143 .store = queue_ra_store,
146 static struct queue_sysfs_entry queue_max_sectors_entry = {
147 .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
148 .show = queue_max_sectors_show,
149 .store = queue_max_sectors_store,
152 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
153 .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
154 .show = queue_max_hw_sectors_show,
157 static struct queue_sysfs_entry queue_iosched_entry = {
158 .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
159 .show = elv_iosched_show,
160 .store = elv_iosched_store,
163 static struct attribute *default_attrs[] = {
164 &queue_requests_entry.attr,
165 &queue_ra_entry.attr,
166 &queue_max_hw_sectors_entry.attr,
167 &queue_max_sectors_entry.attr,
168 &queue_iosched_entry.attr,
172 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
175 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
177 struct queue_sysfs_entry *entry = to_queue(attr);
178 struct request_queue *q =
179 container_of(kobj, struct request_queue, kobj);
184 mutex_lock(&q->sysfs_lock);
185 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
186 mutex_unlock(&q->sysfs_lock);
189 res = entry->show(q, page);
190 mutex_unlock(&q->sysfs_lock);
195 queue_attr_store(struct kobject *kobj, struct attribute *attr,
196 const char *page, size_t length)
198 struct queue_sysfs_entry *entry = to_queue(attr);
199 struct request_queue *q = container_of(kobj, struct request_queue, kobj);
205 mutex_lock(&q->sysfs_lock);
206 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
207 mutex_unlock(&q->sysfs_lock);
210 res = entry->store(q, page, length);
211 mutex_unlock(&q->sysfs_lock);
216 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
217 * @kobj: the kobj belonging of the request queue to be released
220 * blk_cleanup_queue is the pair to blk_init_queue() or
221 * blk_queue_make_request(). It should be called when a request queue is
222 * being released; typically when a block device is being de-registered.
223 * Currently, its primary task it to free all the &struct request
224 * structures that were allocated to the queue and the queue itself.
227 * Hopefully the low level driver will have finished any
228 * outstanding requests first...
230 static void blk_release_queue(struct kobject *kobj)
232 struct request_queue *q =
233 container_of(kobj, struct request_queue, kobj);
234 struct request_list *rl = &q->rq;
239 mempool_destroy(rl->rq_pool);
242 __blk_queue_free_tags(q);
244 blk_trace_shutdown(q);
246 bdi_destroy(&q->backing_dev_info);
247 kmem_cache_free(blk_requestq_cachep, q);
250 static struct sysfs_ops queue_sysfs_ops = {
251 .show = queue_attr_show,
252 .store = queue_attr_store,
255 struct kobj_type blk_queue_ktype = {
256 .sysfs_ops = &queue_sysfs_ops,
257 .default_attrs = default_attrs,
258 .release = blk_release_queue,
261 int blk_register_queue(struct gendisk *disk)
265 struct request_queue *q = disk->queue;
267 if (!q || !q->request_fn)
270 ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
275 kobject_uevent(&q->kobj, KOBJ_ADD);
277 ret = elv_register_queue(q);
279 kobject_uevent(&q->kobj, KOBJ_REMOVE);
280 kobject_del(&q->kobj);
287 void blk_unregister_queue(struct gendisk *disk)
289 struct request_queue *q = disk->queue;
291 if (q && q->request_fn) {
292 elv_unregister_queue(q);
294 kobject_uevent(&q->kobj, KOBJ_REMOVE);
295 kobject_del(&q->kobj);
296 kobject_put(&disk->dev.kobj);