block: Allow changing max_sectors_kb above the default 512
[linux-2.6.git] / 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 long var, char *page)
20 {
21         return sprintf(page, "%lu\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[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
52                 blk_set_queue_congested(q, BLK_RW_SYNC);
53         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
54                 blk_clear_queue_congested(q, BLK_RW_SYNC);
55
56         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
57                 blk_set_queue_congested(q, BLK_RW_ASYNC);
58         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
59                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
60
61         if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
62                 blk_set_queue_full(q, BLK_RW_SYNC);
63         } else if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
64                 blk_clear_queue_full(q, BLK_RW_SYNC);
65                 wake_up(&rl->wait[BLK_RW_SYNC]);
66         }
67
68         if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
69                 blk_set_queue_full(q, BLK_RW_ASYNC);
70         } else if (rl->count[BLK_RW_ASYNC]+1 <= q->nr_requests) {
71                 blk_clear_queue_full(q, BLK_RW_ASYNC);
72                 wake_up(&rl->wait[BLK_RW_ASYNC]);
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         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
81                                         (PAGE_CACHE_SHIFT - 10);
82
83         return queue_var_show(ra_kb, (page));
84 }
85
86 static ssize_t
87 queue_ra_store(struct request_queue *q, const char *page, size_t count)
88 {
89         unsigned long ra_kb;
90         ssize_t ret = queue_var_store(&ra_kb, page, count);
91
92         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
93
94         return ret;
95 }
96
97 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
98 {
99         int max_sectors_kb = queue_max_sectors(q) >> 1;
100
101         return queue_var_show(max_sectors_kb, (page));
102 }
103
104 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
105 {
106         return queue_var_show(queue_logical_block_size(q), page);
107 }
108
109 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
110 {
111         return queue_var_show(queue_physical_block_size(q), page);
112 }
113
114 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
115 {
116         return queue_var_show(queue_io_min(q), page);
117 }
118
119 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
120 {
121         return queue_var_show(queue_io_opt(q), page);
122 }
123
124 static ssize_t
125 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
126 {
127         unsigned long max_sectors_kb,
128                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
129                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
130         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
131
132         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
133                 return -EINVAL;
134
135         spin_lock_irq(q->queue_lock);
136         q->limits.max_sectors = max_sectors_kb << 1;
137         spin_unlock_irq(q->queue_lock);
138
139         return ret;
140 }
141
142 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
143 {
144         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
145
146         return queue_var_show(max_hw_sectors_kb, (page));
147 }
148
149 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
150 {
151         return queue_var_show(!blk_queue_nonrot(q), page);
152 }
153
154 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
155                                   size_t count)
156 {
157         unsigned long nm;
158         ssize_t ret = queue_var_store(&nm, page, count);
159
160         spin_lock_irq(q->queue_lock);
161         if (nm)
162                 queue_flag_clear(QUEUE_FLAG_NONROT, q);
163         else
164                 queue_flag_set(QUEUE_FLAG_NONROT, q);
165         spin_unlock_irq(q->queue_lock);
166
167         return ret;
168 }
169
170 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
171 {
172         return queue_var_show(blk_queue_nomerges(q), page);
173 }
174
175 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
176                                     size_t count)
177 {
178         unsigned long nm;
179         ssize_t ret = queue_var_store(&nm, page, count);
180
181         spin_lock_irq(q->queue_lock);
182         if (nm)
183                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
184         else
185                 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
186         spin_unlock_irq(q->queue_lock);
187
188         return ret;
189 }
190
191 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
192 {
193         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
194
195         return queue_var_show(set, page);
196 }
197
198 static ssize_t
199 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
200 {
201         ssize_t ret = -EINVAL;
202 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
203         unsigned long val;
204
205         ret = queue_var_store(&val, page, count);
206         spin_lock_irq(q->queue_lock);
207         if (val)
208                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
209         else
210                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
211         spin_unlock_irq(q->queue_lock);
212 #endif
213         return ret;
214 }
215
216 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
217 {
218         return queue_var_show(blk_queue_io_stat(q), page);
219 }
220
221 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
222                                    size_t count)
223 {
224         unsigned long stats;
225         ssize_t ret = queue_var_store(&stats, page, count);
226
227         spin_lock_irq(q->queue_lock);
228         if (stats)
229                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
230         else
231                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
232         spin_unlock_irq(q->queue_lock);
233
234         return ret;
235 }
236
237 static struct queue_sysfs_entry queue_requests_entry = {
238         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
239         .show = queue_requests_show,
240         .store = queue_requests_store,
241 };
242
243 static struct queue_sysfs_entry queue_ra_entry = {
244         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
245         .show = queue_ra_show,
246         .store = queue_ra_store,
247 };
248
249 static struct queue_sysfs_entry queue_max_sectors_entry = {
250         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
251         .show = queue_max_sectors_show,
252         .store = queue_max_sectors_store,
253 };
254
255 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
256         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
257         .show = queue_max_hw_sectors_show,
258 };
259
260 static struct queue_sysfs_entry queue_iosched_entry = {
261         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
262         .show = elv_iosched_show,
263         .store = elv_iosched_store,
264 };
265
266 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
267         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
268         .show = queue_logical_block_size_show,
269 };
270
271 static struct queue_sysfs_entry queue_logical_block_size_entry = {
272         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
273         .show = queue_logical_block_size_show,
274 };
275
276 static struct queue_sysfs_entry queue_physical_block_size_entry = {
277         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
278         .show = queue_physical_block_size_show,
279 };
280
281 static struct queue_sysfs_entry queue_io_min_entry = {
282         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
283         .show = queue_io_min_show,
284 };
285
286 static struct queue_sysfs_entry queue_io_opt_entry = {
287         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
288         .show = queue_io_opt_show,
289 };
290
291 static struct queue_sysfs_entry queue_nonrot_entry = {
292         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
293         .show = queue_nonrot_show,
294         .store = queue_nonrot_store,
295 };
296
297 static struct queue_sysfs_entry queue_nomerges_entry = {
298         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
299         .show = queue_nomerges_show,
300         .store = queue_nomerges_store,
301 };
302
303 static struct queue_sysfs_entry queue_rq_affinity_entry = {
304         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
305         .show = queue_rq_affinity_show,
306         .store = queue_rq_affinity_store,
307 };
308
309 static struct queue_sysfs_entry queue_iostats_entry = {
310         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
311         .show = queue_iostats_show,
312         .store = queue_iostats_store,
313 };
314
315 static struct attribute *default_attrs[] = {
316         &queue_requests_entry.attr,
317         &queue_ra_entry.attr,
318         &queue_max_hw_sectors_entry.attr,
319         &queue_max_sectors_entry.attr,
320         &queue_iosched_entry.attr,
321         &queue_hw_sector_size_entry.attr,
322         &queue_logical_block_size_entry.attr,
323         &queue_physical_block_size_entry.attr,
324         &queue_io_min_entry.attr,
325         &queue_io_opt_entry.attr,
326         &queue_nonrot_entry.attr,
327         &queue_nomerges_entry.attr,
328         &queue_rq_affinity_entry.attr,
329         &queue_iostats_entry.attr,
330         NULL,
331 };
332
333 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
334
335 static ssize_t
336 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
337 {
338         struct queue_sysfs_entry *entry = to_queue(attr);
339         struct request_queue *q =
340                 container_of(kobj, struct request_queue, kobj);
341         ssize_t res;
342
343         if (!entry->show)
344                 return -EIO;
345         mutex_lock(&q->sysfs_lock);
346         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
347                 mutex_unlock(&q->sysfs_lock);
348                 return -ENOENT;
349         }
350         res = entry->show(q, page);
351         mutex_unlock(&q->sysfs_lock);
352         return res;
353 }
354
355 static ssize_t
356 queue_attr_store(struct kobject *kobj, struct attribute *attr,
357                     const char *page, size_t length)
358 {
359         struct queue_sysfs_entry *entry = to_queue(attr);
360         struct request_queue *q;
361         ssize_t res;
362
363         if (!entry->store)
364                 return -EIO;
365
366         q = container_of(kobj, struct request_queue, kobj);
367         mutex_lock(&q->sysfs_lock);
368         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
369                 mutex_unlock(&q->sysfs_lock);
370                 return -ENOENT;
371         }
372         res = entry->store(q, page, length);
373         mutex_unlock(&q->sysfs_lock);
374         return res;
375 }
376
377 /**
378  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
379  * @kobj:    the kobj belonging of the request queue to be released
380  *
381  * Description:
382  *     blk_cleanup_queue is the pair to blk_init_queue() or
383  *     blk_queue_make_request().  It should be called when a request queue is
384  *     being released; typically when a block device is being de-registered.
385  *     Currently, its primary task it to free all the &struct request
386  *     structures that were allocated to the queue and the queue itself.
387  *
388  * Caveat:
389  *     Hopefully the low level driver will have finished any
390  *     outstanding requests first...
391  **/
392 static void blk_release_queue(struct kobject *kobj)
393 {
394         struct request_queue *q =
395                 container_of(kobj, struct request_queue, kobj);
396         struct request_list *rl = &q->rq;
397
398         blk_sync_queue(q);
399
400         if (rl->rq_pool)
401                 mempool_destroy(rl->rq_pool);
402
403         if (q->queue_tags)
404                 __blk_queue_free_tags(q);
405
406         blk_trace_shutdown(q);
407
408         bdi_destroy(&q->backing_dev_info);
409         kmem_cache_free(blk_requestq_cachep, q);
410 }
411
412 static struct sysfs_ops queue_sysfs_ops = {
413         .show   = queue_attr_show,
414         .store  = queue_attr_store,
415 };
416
417 struct kobj_type blk_queue_ktype = {
418         .sysfs_ops      = &queue_sysfs_ops,
419         .default_attrs  = default_attrs,
420         .release        = blk_release_queue,
421 };
422
423 int blk_register_queue(struct gendisk *disk)
424 {
425         int ret;
426         struct device *dev = disk_to_dev(disk);
427
428         struct request_queue *q = disk->queue;
429
430         if (WARN_ON(!q))
431                 return -ENXIO;
432
433         ret = blk_trace_init_sysfs(dev);
434         if (ret)
435                 return ret;
436
437         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
438         if (ret < 0)
439                 return ret;
440
441         kobject_uevent(&q->kobj, KOBJ_ADD);
442
443         if (!q->request_fn)
444                 return 0;
445
446         ret = elv_register_queue(q);
447         if (ret) {
448                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
449                 kobject_del(&q->kobj);
450                 return ret;
451         }
452
453         return 0;
454 }
455
456 void blk_unregister_queue(struct gendisk *disk)
457 {
458         struct request_queue *q = disk->queue;
459
460         if (WARN_ON(!q))
461                 return;
462
463         if (q->request_fn) {
464                 elv_unregister_queue(q);
465
466                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
467                 kobject_del(&q->kobj);
468                 kobject_put(&disk_to_dev(disk)->kobj);
469         }
470 }