cfq-iosched: More renaming to better represent wl_class and wl_type
[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         int err;
30         unsigned long v;
31
32         err = strict_strtoul(page, 10, &v);
33         if (err || v > UINT_MAX)
34                 return -EINVAL;
35
36         *var = v;
37
38         return count;
39 }
40
41 static ssize_t queue_requests_show(struct request_queue *q, char *page)
42 {
43         return queue_var_show(q->nr_requests, (page));
44 }
45
46 static ssize_t
47 queue_requests_store(struct request_queue *q, const char *page, size_t count)
48 {
49         struct request_list *rl;
50         unsigned long nr;
51         int ret;
52
53         if (!q->request_fn)
54                 return -EINVAL;
55
56         ret = queue_var_store(&nr, page, count);
57         if (ret < 0)
58                 return ret;
59
60         if (nr < BLKDEV_MIN_RQ)
61                 nr = BLKDEV_MIN_RQ;
62
63         spin_lock_irq(q->queue_lock);
64         q->nr_requests = nr;
65         blk_queue_congestion_threshold(q);
66
67         /* congestion isn't cgroup aware and follows root blkcg for now */
68         rl = &q->root_rl;
69
70         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
71                 blk_set_queue_congested(q, BLK_RW_SYNC);
72         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
73                 blk_clear_queue_congested(q, BLK_RW_SYNC);
74
75         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
76                 blk_set_queue_congested(q, BLK_RW_ASYNC);
77         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
78                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
79
80         blk_queue_for_each_rl(rl, q) {
81                 if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
82                         blk_set_rl_full(rl, BLK_RW_SYNC);
83                 } else {
84                         blk_clear_rl_full(rl, BLK_RW_SYNC);
85                         wake_up(&rl->wait[BLK_RW_SYNC]);
86                 }
87
88                 if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
89                         blk_set_rl_full(rl, BLK_RW_ASYNC);
90                 } else {
91                         blk_clear_rl_full(rl, BLK_RW_ASYNC);
92                         wake_up(&rl->wait[BLK_RW_ASYNC]);
93                 }
94         }
95
96         spin_unlock_irq(q->queue_lock);
97         return ret;
98 }
99
100 static ssize_t queue_ra_show(struct request_queue *q, char *page)
101 {
102         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
103                                         (PAGE_CACHE_SHIFT - 10);
104
105         return queue_var_show(ra_kb, (page));
106 }
107
108 static ssize_t
109 queue_ra_store(struct request_queue *q, const char *page, size_t count)
110 {
111         unsigned long ra_kb;
112         ssize_t ret = queue_var_store(&ra_kb, page, count);
113
114         if (ret < 0)
115                 return ret;
116
117         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
118
119         return ret;
120 }
121
122 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
123 {
124         int max_sectors_kb = queue_max_sectors(q) >> 1;
125
126         return queue_var_show(max_sectors_kb, (page));
127 }
128
129 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
130 {
131         return queue_var_show(queue_max_segments(q), (page));
132 }
133
134 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
135 {
136         return queue_var_show(q->limits.max_integrity_segments, (page));
137 }
138
139 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
140 {
141         if (blk_queue_cluster(q))
142                 return queue_var_show(queue_max_segment_size(q), (page));
143
144         return queue_var_show(PAGE_CACHE_SIZE, (page));
145 }
146
147 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
148 {
149         return queue_var_show(queue_logical_block_size(q), page);
150 }
151
152 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
153 {
154         return queue_var_show(queue_physical_block_size(q), page);
155 }
156
157 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
158 {
159         return queue_var_show(queue_io_min(q), page);
160 }
161
162 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
163 {
164         return queue_var_show(queue_io_opt(q), page);
165 }
166
167 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
168 {
169         return queue_var_show(q->limits.discard_granularity, page);
170 }
171
172 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
173 {
174         return sprintf(page, "%llu\n",
175                        (unsigned long long)q->limits.max_discard_sectors << 9);
176 }
177
178 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
179 {
180         return queue_var_show(queue_discard_zeroes_data(q), page);
181 }
182
183 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
184 {
185         return sprintf(page, "%llu\n",
186                 (unsigned long long)q->limits.max_write_same_sectors << 9);
187 }
188
189
190 static ssize_t
191 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
192 {
193         unsigned long max_sectors_kb,
194                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
195                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
196         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
197
198         if (ret < 0)
199                 return ret;
200
201         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
202                 return -EINVAL;
203
204         spin_lock_irq(q->queue_lock);
205         q->limits.max_sectors = max_sectors_kb << 1;
206         spin_unlock_irq(q->queue_lock);
207
208         return ret;
209 }
210
211 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
212 {
213         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
214
215         return queue_var_show(max_hw_sectors_kb, (page));
216 }
217
218 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
219 static ssize_t                                                          \
220 queue_show_##name(struct request_queue *q, char *page)                  \
221 {                                                                       \
222         int bit;                                                        \
223         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
224         return queue_var_show(neg ? !bit : bit, page);                  \
225 }                                                                       \
226 static ssize_t                                                          \
227 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
228 {                                                                       \
229         unsigned long val;                                              \
230         ssize_t ret;                                                    \
231         ret = queue_var_store(&val, page, count);                       \
232         if (neg)                                                        \
233                 val = !val;                                             \
234                                                                         \
235         spin_lock_irq(q->queue_lock);                                   \
236         if (val)                                                        \
237                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
238         else                                                            \
239                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
240         spin_unlock_irq(q->queue_lock);                                 \
241         return ret;                                                     \
242 }
243
244 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
245 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
246 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
247 #undef QUEUE_SYSFS_BIT_FNS
248
249 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
250 {
251         return queue_var_show((blk_queue_nomerges(q) << 1) |
252                                blk_queue_noxmerges(q), page);
253 }
254
255 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
256                                     size_t count)
257 {
258         unsigned long nm;
259         ssize_t ret = queue_var_store(&nm, page, count);
260
261         if (ret < 0)
262                 return ret;
263
264         spin_lock_irq(q->queue_lock);
265         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
266         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
267         if (nm == 2)
268                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
269         else if (nm)
270                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
271         spin_unlock_irq(q->queue_lock);
272
273         return ret;
274 }
275
276 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
277 {
278         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
279         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
280
281         return queue_var_show(set << force, page);
282 }
283
284 static ssize_t
285 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
286 {
287         ssize_t ret = -EINVAL;
288 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
289         unsigned long val;
290
291         ret = queue_var_store(&val, page, count);
292         if (ret < 0)
293                 return ret;
294
295         spin_lock_irq(q->queue_lock);
296         if (val == 2) {
297                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
298                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
299         } else if (val == 1) {
300                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
301                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
302         } else if (val == 0) {
303                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
304                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
305         }
306         spin_unlock_irq(q->queue_lock);
307 #endif
308         return ret;
309 }
310
311 static struct queue_sysfs_entry queue_requests_entry = {
312         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
313         .show = queue_requests_show,
314         .store = queue_requests_store,
315 };
316
317 static struct queue_sysfs_entry queue_ra_entry = {
318         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
319         .show = queue_ra_show,
320         .store = queue_ra_store,
321 };
322
323 static struct queue_sysfs_entry queue_max_sectors_entry = {
324         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
325         .show = queue_max_sectors_show,
326         .store = queue_max_sectors_store,
327 };
328
329 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
330         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
331         .show = queue_max_hw_sectors_show,
332 };
333
334 static struct queue_sysfs_entry queue_max_segments_entry = {
335         .attr = {.name = "max_segments", .mode = S_IRUGO },
336         .show = queue_max_segments_show,
337 };
338
339 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
340         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
341         .show = queue_max_integrity_segments_show,
342 };
343
344 static struct queue_sysfs_entry queue_max_segment_size_entry = {
345         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
346         .show = queue_max_segment_size_show,
347 };
348
349 static struct queue_sysfs_entry queue_iosched_entry = {
350         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
351         .show = elv_iosched_show,
352         .store = elv_iosched_store,
353 };
354
355 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
356         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
357         .show = queue_logical_block_size_show,
358 };
359
360 static struct queue_sysfs_entry queue_logical_block_size_entry = {
361         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
362         .show = queue_logical_block_size_show,
363 };
364
365 static struct queue_sysfs_entry queue_physical_block_size_entry = {
366         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
367         .show = queue_physical_block_size_show,
368 };
369
370 static struct queue_sysfs_entry queue_io_min_entry = {
371         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
372         .show = queue_io_min_show,
373 };
374
375 static struct queue_sysfs_entry queue_io_opt_entry = {
376         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
377         .show = queue_io_opt_show,
378 };
379
380 static struct queue_sysfs_entry queue_discard_granularity_entry = {
381         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
382         .show = queue_discard_granularity_show,
383 };
384
385 static struct queue_sysfs_entry queue_discard_max_entry = {
386         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
387         .show = queue_discard_max_show,
388 };
389
390 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
391         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
392         .show = queue_discard_zeroes_data_show,
393 };
394
395 static struct queue_sysfs_entry queue_write_same_max_entry = {
396         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
397         .show = queue_write_same_max_show,
398 };
399
400 static struct queue_sysfs_entry queue_nonrot_entry = {
401         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
402         .show = queue_show_nonrot,
403         .store = queue_store_nonrot,
404 };
405
406 static struct queue_sysfs_entry queue_nomerges_entry = {
407         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
408         .show = queue_nomerges_show,
409         .store = queue_nomerges_store,
410 };
411
412 static struct queue_sysfs_entry queue_rq_affinity_entry = {
413         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
414         .show = queue_rq_affinity_show,
415         .store = queue_rq_affinity_store,
416 };
417
418 static struct queue_sysfs_entry queue_iostats_entry = {
419         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
420         .show = queue_show_iostats,
421         .store = queue_store_iostats,
422 };
423
424 static struct queue_sysfs_entry queue_random_entry = {
425         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
426         .show = queue_show_random,
427         .store = queue_store_random,
428 };
429
430 static struct attribute *default_attrs[] = {
431         &queue_requests_entry.attr,
432         &queue_ra_entry.attr,
433         &queue_max_hw_sectors_entry.attr,
434         &queue_max_sectors_entry.attr,
435         &queue_max_segments_entry.attr,
436         &queue_max_integrity_segments_entry.attr,
437         &queue_max_segment_size_entry.attr,
438         &queue_iosched_entry.attr,
439         &queue_hw_sector_size_entry.attr,
440         &queue_logical_block_size_entry.attr,
441         &queue_physical_block_size_entry.attr,
442         &queue_io_min_entry.attr,
443         &queue_io_opt_entry.attr,
444         &queue_discard_granularity_entry.attr,
445         &queue_discard_max_entry.attr,
446         &queue_discard_zeroes_data_entry.attr,
447         &queue_write_same_max_entry.attr,
448         &queue_nonrot_entry.attr,
449         &queue_nomerges_entry.attr,
450         &queue_rq_affinity_entry.attr,
451         &queue_iostats_entry.attr,
452         &queue_random_entry.attr,
453         NULL,
454 };
455
456 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
457
458 static ssize_t
459 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
460 {
461         struct queue_sysfs_entry *entry = to_queue(attr);
462         struct request_queue *q =
463                 container_of(kobj, struct request_queue, kobj);
464         ssize_t res;
465
466         if (!entry->show)
467                 return -EIO;
468         mutex_lock(&q->sysfs_lock);
469         if (blk_queue_dying(q)) {
470                 mutex_unlock(&q->sysfs_lock);
471                 return -ENOENT;
472         }
473         res = entry->show(q, page);
474         mutex_unlock(&q->sysfs_lock);
475         return res;
476 }
477
478 static ssize_t
479 queue_attr_store(struct kobject *kobj, struct attribute *attr,
480                     const char *page, size_t length)
481 {
482         struct queue_sysfs_entry *entry = to_queue(attr);
483         struct request_queue *q;
484         ssize_t res;
485
486         if (!entry->store)
487                 return -EIO;
488
489         q = container_of(kobj, struct request_queue, kobj);
490         mutex_lock(&q->sysfs_lock);
491         if (blk_queue_dying(q)) {
492                 mutex_unlock(&q->sysfs_lock);
493                 return -ENOENT;
494         }
495         res = entry->store(q, page, length);
496         mutex_unlock(&q->sysfs_lock);
497         return res;
498 }
499
500 /**
501  * blk_release_queue: - release a &struct request_queue when it is no longer needed
502  * @kobj:    the kobj belonging to the request queue to be released
503  *
504  * Description:
505  *     blk_release_queue is the pair to blk_init_queue() or
506  *     blk_queue_make_request().  It should be called when a request queue is
507  *     being released; typically when a block device is being de-registered.
508  *     Currently, its primary task it to free all the &struct request
509  *     structures that were allocated to the queue and the queue itself.
510  *
511  * Caveat:
512  *     Hopefully the low level driver will have finished any
513  *     outstanding requests first...
514  **/
515 static void blk_release_queue(struct kobject *kobj)
516 {
517         struct request_queue *q =
518                 container_of(kobj, struct request_queue, kobj);
519
520         blk_sync_queue(q);
521
522         blkcg_exit_queue(q);
523
524         if (q->elevator) {
525                 spin_lock_irq(q->queue_lock);
526                 ioc_clear_queue(q);
527                 spin_unlock_irq(q->queue_lock);
528                 elevator_exit(q->elevator);
529         }
530
531         blk_exit_rl(&q->root_rl);
532
533         if (q->queue_tags)
534                 __blk_queue_free_tags(q);
535
536         blk_trace_shutdown(q);
537
538         bdi_destroy(&q->backing_dev_info);
539
540         ida_simple_remove(&blk_queue_ida, q->id);
541         kmem_cache_free(blk_requestq_cachep, q);
542 }
543
544 static const struct sysfs_ops queue_sysfs_ops = {
545         .show   = queue_attr_show,
546         .store  = queue_attr_store,
547 };
548
549 struct kobj_type blk_queue_ktype = {
550         .sysfs_ops      = &queue_sysfs_ops,
551         .default_attrs  = default_attrs,
552         .release        = blk_release_queue,
553 };
554
555 int blk_register_queue(struct gendisk *disk)
556 {
557         int ret;
558         struct device *dev = disk_to_dev(disk);
559         struct request_queue *q = disk->queue;
560
561         if (WARN_ON(!q))
562                 return -ENXIO;
563
564         /*
565          * Initialization must be complete by now.  Finish the initial
566          * bypass from queue allocation.
567          */
568         blk_queue_bypass_end(q);
569
570         ret = blk_trace_init_sysfs(dev);
571         if (ret)
572                 return ret;
573
574         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
575         if (ret < 0) {
576                 blk_trace_remove_sysfs(dev);
577                 return ret;
578         }
579
580         kobject_uevent(&q->kobj, KOBJ_ADD);
581
582         if (!q->request_fn)
583                 return 0;
584
585         ret = elv_register_queue(q);
586         if (ret) {
587                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
588                 kobject_del(&q->kobj);
589                 blk_trace_remove_sysfs(dev);
590                 kobject_put(&dev->kobj);
591                 return ret;
592         }
593
594         return 0;
595 }
596
597 void blk_unregister_queue(struct gendisk *disk)
598 {
599         struct request_queue *q = disk->queue;
600
601         if (WARN_ON(!q))
602                 return;
603
604         if (q->request_fn)
605                 elv_unregister_queue(q);
606
607         kobject_uevent(&q->kobj, KOBJ_REMOVE);
608         kobject_del(&q->kobj);
609         blk_trace_remove_sysfs(disk_to_dev(disk));
610         kobject_put(&disk_to_dev(disk)->kobj);
611 }