eventfd: remove fput() call from possible IRQ context
[linux/fpc-iii.git] / block / blk-sysfs.c
blob304ec73ab8215f270cbea1a50e870fd8b5b7bf54
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>
10 #include "blk.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);
18 static ssize_t
19 queue_var_show(unsigned int var, char *page)
21 return sprintf(page, "%d\n", var);
24 static ssize_t
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);
30 return count;
33 static ssize_t queue_requests_show(struct request_queue *q, char *page)
35 return queue_var_show(q->nr_requests, (page));
38 static ssize_t
39 queue_requests_store(struct request_queue *q, const char *page, size_t count)
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;
47 spin_lock_irq(q->queue_lock);
48 q->nr_requests = nr;
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);
75 return ret;
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));
85 static ssize_t
86 queue_ra_store(struct request_queue *q, const char *page, size_t count)
88 unsigned long ra_kb;
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);
95 return ret;
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));
105 static ssize_t queue_hw_sector_size_show(struct request_queue *q, char *page)
107 return queue_var_show(q->hardsect_size, page);
110 static ssize_t
111 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
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);
118 if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
119 return -EINVAL;
121 * Take the queue lock to update the readahead and max_sectors
122 * values synchronously:
124 spin_lock_irq(q->queue_lock);
125 q->max_sectors = max_sectors_kb << 1;
126 spin_unlock_irq(q->queue_lock);
128 return ret;
131 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
133 int max_hw_sectors_kb = q->max_hw_sectors >> 1;
135 return queue_var_show(max_hw_sectors_kb, (page));
138 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
140 return queue_var_show(blk_queue_nomerges(q), page);
143 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
144 size_t count)
146 unsigned long nm;
147 ssize_t ret = queue_var_store(&nm, page, count);
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);
155 spin_unlock_irq(q->queue_lock);
156 return ret;
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,
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,
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,
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,
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,
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,
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,
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,
211 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
213 static ssize_t
214 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
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;
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;
228 res = entry->show(q, page);
229 mutex_unlock(&q->sysfs_lock);
230 return res;
233 static ssize_t
234 queue_attr_store(struct kobject *kobj, struct attribute *attr,
235 const char *page, size_t length)
237 struct queue_sysfs_entry *entry = to_queue(attr);
238 struct request_queue *q;
239 ssize_t res;
241 if (!entry->store)
242 return -EIO;
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;
250 res = entry->store(q, page, length);
251 mutex_unlock(&q->sysfs_lock);
252 return res;
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
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.
266 * Caveat:
267 * Hopefully the low level driver will have finished any
268 * outstanding requests first...
270 static void blk_release_queue(struct kobject *kobj)
272 struct request_queue *q =
273 container_of(kobj, struct request_queue, kobj);
274 struct request_list *rl = &q->rq;
276 blk_sync_queue(q);
278 if (rl->rq_pool)
279 mempool_destroy(rl->rq_pool);
281 if (q->queue_tags)
282 __blk_queue_free_tags(q);
284 blk_trace_shutdown(q);
286 bdi_destroy(&q->backing_dev_info);
287 kmem_cache_free(blk_requestq_cachep, q);
290 static struct sysfs_ops queue_sysfs_ops = {
291 .show = queue_attr_show,
292 .store = queue_attr_store,
295 struct kobj_type blk_queue_ktype = {
296 .sysfs_ops = &queue_sysfs_ops,
297 .default_attrs = default_attrs,
298 .release = blk_release_queue,
301 int blk_register_queue(struct gendisk *disk)
303 int ret;
305 struct request_queue *q = disk->queue;
307 if (WARN_ON(!q))
308 return -ENXIO;
310 if (!q->request_fn)
311 return 0;
313 ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
314 "%s", "queue");
315 if (ret < 0)
316 return ret;
318 kobject_uevent(&q->kobj, KOBJ_ADD);
320 ret = elv_register_queue(q);
321 if (ret) {
322 kobject_uevent(&q->kobj, KOBJ_REMOVE);
323 kobject_del(&q->kobj);
324 return ret;
327 return 0;
330 void blk_unregister_queue(struct gendisk *disk)
332 struct request_queue *q = disk->queue;
334 if (WARN_ON(!q))
335 return;
337 if (q->request_fn) {
338 elv_unregister_queue(q);
340 kobject_uevent(&q->kobj, KOBJ_REMOVE);
341 kobject_del(&q->kobj);
342 kobject_put(&disk->dev.kobj);