Expose hardware sector size
[linux-2.6] / block / blk-sysfs.c
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 = container_of(kobj, struct request_queue, kobj);
211
212         ssize_t res;
213
214         if (!entry->store)
215                 return -EIO;
216         mutex_lock(&q->sysfs_lock);
217         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
218                 mutex_unlock(&q->sysfs_lock);
219                 return -ENOENT;
220         }
221         res = entry->store(q, page, length);
222         mutex_unlock(&q->sysfs_lock);
223         return res;
224 }
225
226 /**
227  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
228  * @kobj:    the kobj belonging of the request queue to be released
229  *
230  * Description:
231  *     blk_cleanup_queue is the pair to blk_init_queue() or
232  *     blk_queue_make_request().  It should be called when a request queue is
233  *     being released; typically when a block device is being de-registered.
234  *     Currently, its primary task it to free all the &struct request
235  *     structures that were allocated to the queue and the queue itself.
236  *
237  * Caveat:
238  *     Hopefully the low level driver will have finished any
239  *     outstanding requests first...
240  **/
241 static void blk_release_queue(struct kobject *kobj)
242 {
243         struct request_queue *q =
244                 container_of(kobj, struct request_queue, kobj);
245         struct request_list *rl = &q->rq;
246
247         blk_sync_queue(q);
248
249         if (rl->rq_pool)
250                 mempool_destroy(rl->rq_pool);
251
252         if (q->queue_tags)
253                 __blk_queue_free_tags(q);
254
255         blk_trace_shutdown(q);
256
257         bdi_destroy(&q->backing_dev_info);
258         kmem_cache_free(blk_requestq_cachep, q);
259 }
260
261 static struct sysfs_ops queue_sysfs_ops = {
262         .show   = queue_attr_show,
263         .store  = queue_attr_store,
264 };
265
266 struct kobj_type blk_queue_ktype = {
267         .sysfs_ops      = &queue_sysfs_ops,
268         .default_attrs  = default_attrs,
269         .release        = blk_release_queue,
270 };
271
272 int blk_register_queue(struct gendisk *disk)
273 {
274         int ret;
275
276         struct request_queue *q = disk->queue;
277
278         if (!q || !q->request_fn)
279                 return -ENXIO;
280
281         ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
282                           "%s", "queue");
283         if (ret < 0)
284                 return ret;
285
286         kobject_uevent(&q->kobj, KOBJ_ADD);
287
288         ret = elv_register_queue(q);
289         if (ret) {
290                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
291                 kobject_del(&q->kobj);
292                 return ret;
293         }
294
295         return 0;
296 }
297
298 void blk_unregister_queue(struct gendisk *disk)
299 {
300         struct request_queue *q = disk->queue;
301
302         if (q && q->request_fn) {
303                 elv_unregister_queue(q);
304
305                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
306                 kobject_del(&q->kobj);
307                 kobject_put(&disk->dev.kobj);
308         }
309 }