00cdc987b5259da2d1832d4418c75f4621571405
[linux-3.10.git] / block / blk-sysfs.c
1 /*
2  * Functions related to sysfs handling
3  */
4 #include <linux/kernel.h>
5 #include <linux/slab.h>
6 #include <linux/module.h>
7 #include <linux/bio.h>
8 #include <linux/blkdev.h>
9 #include <linux/blktrace_api.h>
10
11 #include "blk.h"
12 #include "blk-cgroup.h"
13
14 struct queue_sysfs_entry {
15         struct attribute attr;
16         ssize_t (*show)(struct request_queue *, char *);
17         ssize_t (*store)(struct request_queue *, const char *, size_t);
18 };
19
20 static ssize_t
21 queue_var_show(unsigned long var, char *page)
22 {
23         return sprintf(page, "%lu\n", var);
24 }
25
26 static ssize_t
27 queue_var_store(unsigned long *var, const char *page, size_t count)
28 {
29         char *p = (char *) page;
30
31         *var = simple_strtoul(p, &p, 10);
32         return count;
33 }
34
35 static ssize_t queue_requests_show(struct request_queue *q, char *page)
36 {
37         return queue_var_show(q->nr_requests, (page));
38 }
39
40 static ssize_t
41 queue_requests_store(struct request_queue *q, const char *page, size_t count)
42 {
43         struct request_list *rl = &q->rq;
44         unsigned long nr;
45         int ret;
46
47         if (!q->request_fn)
48                 return -EINVAL;
49
50         ret = queue_var_store(&nr, page, count);
51         if (nr < BLKDEV_MIN_RQ)
52                 nr = BLKDEV_MIN_RQ;
53
54         spin_lock_irq(q->queue_lock);
55         q->nr_requests = nr;
56         blk_queue_congestion_threshold(q);
57
58         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
59                 blk_set_queue_congested(q, BLK_RW_SYNC);
60         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
61                 blk_clear_queue_congested(q, BLK_RW_SYNC);
62
63         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
64                 blk_set_queue_congested(q, BLK_RW_ASYNC);
65         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
66                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
67
68         if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
69                 blk_set_queue_full(q, BLK_RW_SYNC);
70         } else {
71                 blk_clear_queue_full(q, BLK_RW_SYNC);
72                 wake_up(&rl->wait[BLK_RW_SYNC]);
73         }
74
75         if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
76                 blk_set_queue_full(q, BLK_RW_ASYNC);
77         } else {
78                 blk_clear_queue_full(q, BLK_RW_ASYNC);
79                 wake_up(&rl->wait[BLK_RW_ASYNC]);
80         }
81         spin_unlock_irq(q->queue_lock);
82         return ret;
83 }
84
85 static ssize_t queue_ra_show(struct request_queue *q, char *page)
86 {
87         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
88                                         (PAGE_CACHE_SHIFT - 10);
89
90         return queue_var_show(ra_kb, (page));
91 }
92
93 static ssize_t
94 queue_ra_store(struct request_queue *q, const char *page, size_t count)
95 {
96         unsigned long ra_kb;
97         ssize_t ret = queue_var_store(&ra_kb, page, count);
98
99         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
100
101         return ret;
102 }
103
104 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
105 {
106         int max_sectors_kb = queue_max_sectors(q) >> 1;
107
108         return queue_var_show(max_sectors_kb, (page));
109 }
110
111 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
112 {
113         return queue_var_show(queue_max_segments(q), (page));
114 }
115
116 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
117 {
118         return queue_var_show(q->limits.max_integrity_segments, (page));
119 }
120
121 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
122 {
123         if (blk_queue_cluster(q))
124                 return queue_var_show(queue_max_segment_size(q), (page));
125
126         return queue_var_show(PAGE_CACHE_SIZE, (page));
127 }
128
129 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
130 {
131         return queue_var_show(queue_logical_block_size(q), page);
132 }
133
134 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
135 {
136         return queue_var_show(queue_physical_block_size(q), page);
137 }
138
139 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
140 {
141         return queue_var_show(queue_io_min(q), page);
142 }
143
144 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
145 {
146         return queue_var_show(queue_io_opt(q), page);
147 }
148
149 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
150 {
151         return queue_var_show(q->limits.discard_granularity, page);
152 }
153
154 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
155 {
156         return sprintf(page, "%llu\n",
157                        (unsigned long long)q->limits.max_discard_sectors << 9);
158 }
159
160 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
161 {
162         return queue_var_show(queue_discard_zeroes_data(q), page);
163 }
164
165 static ssize_t
166 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
167 {
168         unsigned long max_sectors_kb,
169                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
170                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
171         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
172
173         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
174                 return -EINVAL;
175
176         spin_lock_irq(q->queue_lock);
177         q->limits.max_sectors = max_sectors_kb << 1;
178         spin_unlock_irq(q->queue_lock);
179
180         return ret;
181 }
182
183 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
184 {
185         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
186
187         return queue_var_show(max_hw_sectors_kb, (page));
188 }
189
190 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
191 static ssize_t                                                          \
192 queue_show_##name(struct request_queue *q, char *page)                  \
193 {                                                                       \
194         int bit;                                                        \
195         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
196         return queue_var_show(neg ? !bit : bit, page);                  \
197 }                                                                       \
198 static ssize_t                                                          \
199 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
200 {                                                                       \
201         unsigned long val;                                              \
202         ssize_t ret;                                                    \
203         ret = queue_var_store(&val, page, count);                       \
204         if (neg)                                                        \
205                 val = !val;                                             \
206                                                                         \
207         spin_lock_irq(q->queue_lock);                                   \
208         if (val)                                                        \
209                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
210         else                                                            \
211                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
212         spin_unlock_irq(q->queue_lock);                                 \
213         return ret;                                                     \
214 }
215
216 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
217 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
218 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
219 #undef QUEUE_SYSFS_BIT_FNS
220
221 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
222 {
223         return queue_var_show((blk_queue_nomerges(q) << 1) |
224                                blk_queue_noxmerges(q), page);
225 }
226
227 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
228                                     size_t count)
229 {
230         unsigned long nm;
231         ssize_t ret = queue_var_store(&nm, page, count);
232
233         spin_lock_irq(q->queue_lock);
234         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
235         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
236         if (nm == 2)
237                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
238         else if (nm)
239                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
240         spin_unlock_irq(q->queue_lock);
241
242         return ret;
243 }
244
245 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
246 {
247         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
248         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
249
250         return queue_var_show(set << force, page);
251 }
252
253 static ssize_t
254 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
255 {
256         ssize_t ret = -EINVAL;
257 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
258         unsigned long val;
259
260         ret = queue_var_store(&val, page, count);
261         spin_lock_irq(q->queue_lock);
262         if (val == 2) {
263                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
264                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
265         } else if (val == 1) {
266                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
267                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
268         } else if (val == 0) {
269                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
270                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
271         }
272         spin_unlock_irq(q->queue_lock);
273 #endif
274         return ret;
275 }
276
277 static struct queue_sysfs_entry queue_requests_entry = {
278         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
279         .show = queue_requests_show,
280         .store = queue_requests_store,
281 };
282
283 static struct queue_sysfs_entry queue_ra_entry = {
284         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
285         .show = queue_ra_show,
286         .store = queue_ra_store,
287 };
288
289 static struct queue_sysfs_entry queue_max_sectors_entry = {
290         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
291         .show = queue_max_sectors_show,
292         .store = queue_max_sectors_store,
293 };
294
295 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
296         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
297         .show = queue_max_hw_sectors_show,
298 };
299
300 static struct queue_sysfs_entry queue_max_segments_entry = {
301         .attr = {.name = "max_segments", .mode = S_IRUGO },
302         .show = queue_max_segments_show,
303 };
304
305 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
306         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
307         .show = queue_max_integrity_segments_show,
308 };
309
310 static struct queue_sysfs_entry queue_max_segment_size_entry = {
311         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
312         .show = queue_max_segment_size_show,
313 };
314
315 static struct queue_sysfs_entry queue_iosched_entry = {
316         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
317         .show = elv_iosched_show,
318         .store = elv_iosched_store,
319 };
320
321 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
322         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
323         .show = queue_logical_block_size_show,
324 };
325
326 static struct queue_sysfs_entry queue_logical_block_size_entry = {
327         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
328         .show = queue_logical_block_size_show,
329 };
330
331 static struct queue_sysfs_entry queue_physical_block_size_entry = {
332         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
333         .show = queue_physical_block_size_show,
334 };
335
336 static struct queue_sysfs_entry queue_io_min_entry = {
337         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
338         .show = queue_io_min_show,
339 };
340
341 static struct queue_sysfs_entry queue_io_opt_entry = {
342         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
343         .show = queue_io_opt_show,
344 };
345
346 static struct queue_sysfs_entry queue_discard_granularity_entry = {
347         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
348         .show = queue_discard_granularity_show,
349 };
350
351 static struct queue_sysfs_entry queue_discard_max_entry = {
352         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
353         .show = queue_discard_max_show,
354 };
355
356 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
357         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
358         .show = queue_discard_zeroes_data_show,
359 };
360
361 static struct queue_sysfs_entry queue_nonrot_entry = {
362         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
363         .show = queue_show_nonrot,
364         .store = queue_store_nonrot,
365 };
366
367 static struct queue_sysfs_entry queue_nomerges_entry = {
368         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
369         .show = queue_nomerges_show,
370         .store = queue_nomerges_store,
371 };
372
373 static struct queue_sysfs_entry queue_rq_affinity_entry = {
374         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
375         .show = queue_rq_affinity_show,
376         .store = queue_rq_affinity_store,
377 };
378
379 static struct queue_sysfs_entry queue_iostats_entry = {
380         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
381         .show = queue_show_iostats,
382         .store = queue_store_iostats,
383 };
384
385 static struct queue_sysfs_entry queue_random_entry = {
386         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
387         .show = queue_show_random,
388         .store = queue_store_random,
389 };
390
391 static struct attribute *default_attrs[] = {
392         &queue_requests_entry.attr,
393         &queue_ra_entry.attr,
394         &queue_max_hw_sectors_entry.attr,
395         &queue_max_sectors_entry.attr,
396         &queue_max_segments_entry.attr,
397         &queue_max_integrity_segments_entry.attr,
398         &queue_max_segment_size_entry.attr,
399         &queue_iosched_entry.attr,
400         &queue_hw_sector_size_entry.attr,
401         &queue_logical_block_size_entry.attr,
402         &queue_physical_block_size_entry.attr,
403         &queue_io_min_entry.attr,
404         &queue_io_opt_entry.attr,
405         &queue_discard_granularity_entry.attr,
406         &queue_discard_max_entry.attr,
407         &queue_discard_zeroes_data_entry.attr,
408         &queue_nonrot_entry.attr,
409         &queue_nomerges_entry.attr,
410         &queue_rq_affinity_entry.attr,
411         &queue_iostats_entry.attr,
412         &queue_random_entry.attr,
413         NULL,
414 };
415
416 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
417
418 static ssize_t
419 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
420 {
421         struct queue_sysfs_entry *entry = to_queue(attr);
422         struct request_queue *q =
423                 container_of(kobj, struct request_queue, kobj);
424         ssize_t res;
425
426         if (!entry->show)
427                 return -EIO;
428         mutex_lock(&q->sysfs_lock);
429         if (blk_queue_dead(q)) {
430                 mutex_unlock(&q->sysfs_lock);
431                 return -ENOENT;
432         }
433         res = entry->show(q, page);
434         mutex_unlock(&q->sysfs_lock);
435         return res;
436 }
437
438 static ssize_t
439 queue_attr_store(struct kobject *kobj, struct attribute *attr,
440                     const char *page, size_t length)
441 {
442         struct queue_sysfs_entry *entry = to_queue(attr);
443         struct request_queue *q;
444         ssize_t res;
445
446         if (!entry->store)
447                 return -EIO;
448
449         q = container_of(kobj, struct request_queue, kobj);
450         mutex_lock(&q->sysfs_lock);
451         if (blk_queue_dead(q)) {
452                 mutex_unlock(&q->sysfs_lock);
453                 return -ENOENT;
454         }
455         res = entry->store(q, page, length);
456         mutex_unlock(&q->sysfs_lock);
457         return res;
458 }
459
460 /**
461  * blk_release_queue: - release a &struct request_queue when it is no longer needed
462  * @kobj:    the kobj belonging to the request queue to be released
463  *
464  * Description:
465  *     blk_release_queue is the pair to blk_init_queue() or
466  *     blk_queue_make_request().  It should be called when a request queue is
467  *     being released; typically when a block device is being de-registered.
468  *     Currently, its primary task it to free all the &struct request
469  *     structures that were allocated to the queue and the queue itself.
470  *
471  * Caveat:
472  *     Hopefully the low level driver will have finished any
473  *     outstanding requests first...
474  **/
475 static void blk_release_queue(struct kobject *kobj)
476 {
477         struct request_queue *q =
478                 container_of(kobj, struct request_queue, kobj);
479         struct request_list *rl = &q->rq;
480
481         blk_sync_queue(q);
482
483         if (q->elevator) {
484                 spin_lock_irq(q->queue_lock);
485                 ioc_clear_queue(q);
486                 spin_unlock_irq(q->queue_lock);
487                 elevator_exit(q->elevator);
488         }
489
490         blkcg_exit_queue(q);
491
492         if (rl->rq_pool)
493                 mempool_destroy(rl->rq_pool);
494
495         if (q->queue_tags)
496                 __blk_queue_free_tags(q);
497
498         blk_trace_shutdown(q);
499
500         bdi_destroy(&q->backing_dev_info);
501
502         ida_simple_remove(&blk_queue_ida, q->id);
503         kmem_cache_free(blk_requestq_cachep, q);
504 }
505
506 static const struct sysfs_ops queue_sysfs_ops = {
507         .show   = queue_attr_show,
508         .store  = queue_attr_store,
509 };
510
511 struct kobj_type blk_queue_ktype = {
512         .sysfs_ops      = &queue_sysfs_ops,
513         .default_attrs  = default_attrs,
514         .release        = blk_release_queue,
515 };
516
517 int blk_register_queue(struct gendisk *disk)
518 {
519         int ret;
520         struct device *dev = disk_to_dev(disk);
521         struct request_queue *q = disk->queue;
522
523         if (WARN_ON(!q))
524                 return -ENXIO;
525
526         ret = blk_trace_init_sysfs(dev);
527         if (ret)
528                 return ret;
529
530         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
531         if (ret < 0) {
532                 blk_trace_remove_sysfs(dev);
533                 return ret;
534         }
535
536         kobject_uevent(&q->kobj, KOBJ_ADD);
537
538         if (!q->request_fn)
539                 return 0;
540
541         ret = elv_register_queue(q);
542         if (ret) {
543                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
544                 kobject_del(&q->kobj);
545                 blk_trace_remove_sysfs(dev);
546                 kobject_put(&dev->kobj);
547                 return ret;
548         }
549
550         return 0;
551 }
552
553 void blk_unregister_queue(struct gendisk *disk)
554 {
555         struct request_queue *q = disk->queue;
556
557         if (WARN_ON(!q))
558                 return;
559
560         if (q->request_fn)
561                 elv_unregister_queue(q);
562
563         kobject_uevent(&q->kobj, KOBJ_REMOVE);
564         kobject_del(&q->kobj);
565         blk_trace_remove_sysfs(disk_to_dev(disk));
566         kobject_put(&disk_to_dev(disk)->kobj);
567 }