Merge branch 'mailbox-for-next' of git://git.linaro.org/landing-teams/working/fujitsu...
[firefly-linux-kernel-4.4.55.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/backing-dev.h>
10 #include <linux/blktrace_api.h>
11 #include <linux/blk-mq.h>
12 #include <linux/blk-cgroup.h>
13
14 #include "blk.h"
15 #include "blk-mq.h"
16
17 struct queue_sysfs_entry {
18         struct attribute attr;
19         ssize_t (*show)(struct request_queue *, char *);
20         ssize_t (*store)(struct request_queue *, const char *, size_t);
21 };
22
23 static ssize_t
24 queue_var_show(unsigned long var, char *page)
25 {
26         return sprintf(page, "%lu\n", var);
27 }
28
29 static ssize_t
30 queue_var_store(unsigned long *var, const char *page, size_t count)
31 {
32         int err;
33         unsigned long v;
34
35         err = kstrtoul(page, 10, &v);
36         if (err || v > UINT_MAX)
37                 return -EINVAL;
38
39         *var = v;
40
41         return count;
42 }
43
44 static ssize_t queue_requests_show(struct request_queue *q, char *page)
45 {
46         return queue_var_show(q->nr_requests, (page));
47 }
48
49 static ssize_t
50 queue_requests_store(struct request_queue *q, const char *page, size_t count)
51 {
52         unsigned long nr;
53         int ret, err;
54
55         if (!q->request_fn && !q->mq_ops)
56                 return -EINVAL;
57
58         ret = queue_var_store(&nr, page, count);
59         if (ret < 0)
60                 return ret;
61
62         if (nr < BLKDEV_MIN_RQ)
63                 nr = BLKDEV_MIN_RQ;
64
65         if (q->request_fn)
66                 err = blk_update_nr_requests(q, nr);
67         else
68                 err = blk_mq_update_nr_requests(q, nr);
69
70         if (err)
71                 return err;
72
73         return ret;
74 }
75
76 static ssize_t queue_ra_show(struct request_queue *q, char *page)
77 {
78         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
79                                         (PAGE_CACHE_SHIFT - 10);
80
81         return queue_var_show(ra_kb, (page));
82 }
83
84 static ssize_t
85 queue_ra_store(struct request_queue *q, const char *page, size_t count)
86 {
87         unsigned long ra_kb;
88         ssize_t ret = queue_var_store(&ra_kb, page, count);
89
90         if (ret < 0)
91                 return ret;
92
93         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
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 = queue_max_sectors(q) >> 1;
101
102         return queue_var_show(max_sectors_kb, (page));
103 }
104
105 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
106 {
107         return queue_var_show(queue_max_segments(q), (page));
108 }
109
110 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
111 {
112         return queue_var_show(q->limits.max_integrity_segments, (page));
113 }
114
115 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
116 {
117         if (blk_queue_cluster(q))
118                 return queue_var_show(queue_max_segment_size(q), (page));
119
120         return queue_var_show(PAGE_CACHE_SIZE, (page));
121 }
122
123 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
124 {
125         return queue_var_show(queue_logical_block_size(q), page);
126 }
127
128 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
129 {
130         return queue_var_show(queue_physical_block_size(q), page);
131 }
132
133 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
134 {
135         return queue_var_show(queue_io_min(q), page);
136 }
137
138 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
139 {
140         return queue_var_show(queue_io_opt(q), page);
141 }
142
143 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
144 {
145         return queue_var_show(q->limits.discard_granularity, page);
146 }
147
148 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
149 {
150         unsigned long long val;
151
152         val = q->limits.max_hw_discard_sectors << 9;
153         return sprintf(page, "%llu\n", val);
154 }
155
156 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
157 {
158         return sprintf(page, "%llu\n",
159                        (unsigned long long)q->limits.max_discard_sectors << 9);
160 }
161
162 static ssize_t queue_discard_max_store(struct request_queue *q,
163                                        const char *page, size_t count)
164 {
165         unsigned long max_discard;
166         ssize_t ret = queue_var_store(&max_discard, page, count);
167
168         if (ret < 0)
169                 return ret;
170
171         if (max_discard & (q->limits.discard_granularity - 1))
172                 return -EINVAL;
173
174         max_discard >>= 9;
175         if (max_discard > UINT_MAX)
176                 return -EINVAL;
177
178         if (max_discard > q->limits.max_hw_discard_sectors)
179                 max_discard = q->limits.max_hw_discard_sectors;
180
181         q->limits.max_discard_sectors = max_discard;
182         return ret;
183 }
184
185 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
186 {
187         return queue_var_show(queue_discard_zeroes_data(q), page);
188 }
189
190 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
191 {
192         return sprintf(page, "%llu\n",
193                 (unsigned long long)q->limits.max_write_same_sectors << 9);
194 }
195
196
197 static ssize_t
198 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
199 {
200         unsigned long max_sectors_kb,
201                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
202                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
203         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
204
205         if (ret < 0)
206                 return ret;
207
208         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
209                 return -EINVAL;
210
211         spin_lock_irq(q->queue_lock);
212         q->limits.max_sectors = max_sectors_kb << 1;
213         spin_unlock_irq(q->queue_lock);
214
215         return ret;
216 }
217
218 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
219 {
220         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
221
222         return queue_var_show(max_hw_sectors_kb, (page));
223 }
224
225 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
226 static ssize_t                                                          \
227 queue_show_##name(struct request_queue *q, char *page)                  \
228 {                                                                       \
229         int bit;                                                        \
230         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
231         return queue_var_show(neg ? !bit : bit, page);                  \
232 }                                                                       \
233 static ssize_t                                                          \
234 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
235 {                                                                       \
236         unsigned long val;                                              \
237         ssize_t ret;                                                    \
238         ret = queue_var_store(&val, page, count);                       \
239         if (ret < 0)                                                    \
240                  return ret;                                            \
241         if (neg)                                                        \
242                 val = !val;                                             \
243                                                                         \
244         spin_lock_irq(q->queue_lock);                                   \
245         if (val)                                                        \
246                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
247         else                                                            \
248                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
249         spin_unlock_irq(q->queue_lock);                                 \
250         return ret;                                                     \
251 }
252
253 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
254 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
255 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
256 #undef QUEUE_SYSFS_BIT_FNS
257
258 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
259 {
260         return queue_var_show((blk_queue_nomerges(q) << 1) |
261                                blk_queue_noxmerges(q), page);
262 }
263
264 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
265                                     size_t count)
266 {
267         unsigned long nm;
268         ssize_t ret = queue_var_store(&nm, page, count);
269
270         if (ret < 0)
271                 return ret;
272
273         spin_lock_irq(q->queue_lock);
274         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
275         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
276         if (nm == 2)
277                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
278         else if (nm)
279                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
280         spin_unlock_irq(q->queue_lock);
281
282         return ret;
283 }
284
285 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
286 {
287         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
288         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
289
290         return queue_var_show(set << force, page);
291 }
292
293 static ssize_t
294 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
295 {
296         ssize_t ret = -EINVAL;
297 #ifdef CONFIG_SMP
298         unsigned long val;
299
300         ret = queue_var_store(&val, page, count);
301         if (ret < 0)
302                 return ret;
303
304         spin_lock_irq(q->queue_lock);
305         if (val == 2) {
306                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
307                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
308         } else if (val == 1) {
309                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
310                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
311         } else if (val == 0) {
312                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
313                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
314         }
315         spin_unlock_irq(q->queue_lock);
316 #endif
317         return ret;
318 }
319
320 static struct queue_sysfs_entry queue_requests_entry = {
321         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
322         .show = queue_requests_show,
323         .store = queue_requests_store,
324 };
325
326 static struct queue_sysfs_entry queue_ra_entry = {
327         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
328         .show = queue_ra_show,
329         .store = queue_ra_store,
330 };
331
332 static struct queue_sysfs_entry queue_max_sectors_entry = {
333         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
334         .show = queue_max_sectors_show,
335         .store = queue_max_sectors_store,
336 };
337
338 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
339         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
340         .show = queue_max_hw_sectors_show,
341 };
342
343 static struct queue_sysfs_entry queue_max_segments_entry = {
344         .attr = {.name = "max_segments", .mode = S_IRUGO },
345         .show = queue_max_segments_show,
346 };
347
348 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
349         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
350         .show = queue_max_integrity_segments_show,
351 };
352
353 static struct queue_sysfs_entry queue_max_segment_size_entry = {
354         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
355         .show = queue_max_segment_size_show,
356 };
357
358 static struct queue_sysfs_entry queue_iosched_entry = {
359         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
360         .show = elv_iosched_show,
361         .store = elv_iosched_store,
362 };
363
364 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
365         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
366         .show = queue_logical_block_size_show,
367 };
368
369 static struct queue_sysfs_entry queue_logical_block_size_entry = {
370         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
371         .show = queue_logical_block_size_show,
372 };
373
374 static struct queue_sysfs_entry queue_physical_block_size_entry = {
375         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
376         .show = queue_physical_block_size_show,
377 };
378
379 static struct queue_sysfs_entry queue_io_min_entry = {
380         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
381         .show = queue_io_min_show,
382 };
383
384 static struct queue_sysfs_entry queue_io_opt_entry = {
385         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
386         .show = queue_io_opt_show,
387 };
388
389 static struct queue_sysfs_entry queue_discard_granularity_entry = {
390         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
391         .show = queue_discard_granularity_show,
392 };
393
394 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
395         .attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
396         .show = queue_discard_max_hw_show,
397 };
398
399 static struct queue_sysfs_entry queue_discard_max_entry = {
400         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
401         .show = queue_discard_max_show,
402         .store = queue_discard_max_store,
403 };
404
405 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
406         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
407         .show = queue_discard_zeroes_data_show,
408 };
409
410 static struct queue_sysfs_entry queue_write_same_max_entry = {
411         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
412         .show = queue_write_same_max_show,
413 };
414
415 static struct queue_sysfs_entry queue_nonrot_entry = {
416         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
417         .show = queue_show_nonrot,
418         .store = queue_store_nonrot,
419 };
420
421 static struct queue_sysfs_entry queue_nomerges_entry = {
422         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
423         .show = queue_nomerges_show,
424         .store = queue_nomerges_store,
425 };
426
427 static struct queue_sysfs_entry queue_rq_affinity_entry = {
428         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
429         .show = queue_rq_affinity_show,
430         .store = queue_rq_affinity_store,
431 };
432
433 static struct queue_sysfs_entry queue_iostats_entry = {
434         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
435         .show = queue_show_iostats,
436         .store = queue_store_iostats,
437 };
438
439 static struct queue_sysfs_entry queue_random_entry = {
440         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
441         .show = queue_show_random,
442         .store = queue_store_random,
443 };
444
445 static struct attribute *default_attrs[] = {
446         &queue_requests_entry.attr,
447         &queue_ra_entry.attr,
448         &queue_max_hw_sectors_entry.attr,
449         &queue_max_sectors_entry.attr,
450         &queue_max_segments_entry.attr,
451         &queue_max_integrity_segments_entry.attr,
452         &queue_max_segment_size_entry.attr,
453         &queue_iosched_entry.attr,
454         &queue_hw_sector_size_entry.attr,
455         &queue_logical_block_size_entry.attr,
456         &queue_physical_block_size_entry.attr,
457         &queue_io_min_entry.attr,
458         &queue_io_opt_entry.attr,
459         &queue_discard_granularity_entry.attr,
460         &queue_discard_max_entry.attr,
461         &queue_discard_max_hw_entry.attr,
462         &queue_discard_zeroes_data_entry.attr,
463         &queue_write_same_max_entry.attr,
464         &queue_nonrot_entry.attr,
465         &queue_nomerges_entry.attr,
466         &queue_rq_affinity_entry.attr,
467         &queue_iostats_entry.attr,
468         &queue_random_entry.attr,
469         NULL,
470 };
471
472 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
473
474 static ssize_t
475 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
476 {
477         struct queue_sysfs_entry *entry = to_queue(attr);
478         struct request_queue *q =
479                 container_of(kobj, struct request_queue, kobj);
480         ssize_t res;
481
482         if (!entry->show)
483                 return -EIO;
484         mutex_lock(&q->sysfs_lock);
485         if (blk_queue_dying(q)) {
486                 mutex_unlock(&q->sysfs_lock);
487                 return -ENOENT;
488         }
489         res = entry->show(q, page);
490         mutex_unlock(&q->sysfs_lock);
491         return res;
492 }
493
494 static ssize_t
495 queue_attr_store(struct kobject *kobj, struct attribute *attr,
496                     const char *page, size_t length)
497 {
498         struct queue_sysfs_entry *entry = to_queue(attr);
499         struct request_queue *q;
500         ssize_t res;
501
502         if (!entry->store)
503                 return -EIO;
504
505         q = container_of(kobj, struct request_queue, kobj);
506         mutex_lock(&q->sysfs_lock);
507         if (blk_queue_dying(q)) {
508                 mutex_unlock(&q->sysfs_lock);
509                 return -ENOENT;
510         }
511         res = entry->store(q, page, length);
512         mutex_unlock(&q->sysfs_lock);
513         return res;
514 }
515
516 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
517 {
518         struct request_queue *q = container_of(rcu_head, struct request_queue,
519                                                rcu_head);
520         kmem_cache_free(blk_requestq_cachep, q);
521 }
522
523 /**
524  * blk_release_queue: - release a &struct request_queue when it is no longer needed
525  * @kobj:    the kobj belonging to the request queue to be released
526  *
527  * Description:
528  *     blk_release_queue is the pair to blk_init_queue() or
529  *     blk_queue_make_request().  It should be called when a request queue is
530  *     being released; typically when a block device is being de-registered.
531  *     Currently, its primary task it to free all the &struct request
532  *     structures that were allocated to the queue and the queue itself.
533  *
534  * Note:
535  *     The low level driver must have finished any outstanding requests first
536  *     via blk_cleanup_queue().
537  **/
538 static void blk_release_queue(struct kobject *kobj)
539 {
540         struct request_queue *q =
541                 container_of(kobj, struct request_queue, kobj);
542
543         bdi_exit(&q->backing_dev_info);
544         blkcg_exit_queue(q);
545
546         if (q->elevator) {
547                 spin_lock_irq(q->queue_lock);
548                 ioc_clear_queue(q);
549                 spin_unlock_irq(q->queue_lock);
550                 elevator_exit(q->elevator);
551         }
552
553         blk_exit_rl(&q->root_rl);
554
555         if (q->queue_tags)
556                 __blk_queue_free_tags(q);
557
558         if (!q->mq_ops)
559                 blk_free_flush_queue(q->fq);
560         else
561                 blk_mq_release(q);
562
563         blk_trace_shutdown(q);
564
565         if (q->bio_split)
566                 bioset_free(q->bio_split);
567
568         ida_simple_remove(&blk_queue_ida, q->id);
569         call_rcu(&q->rcu_head, blk_free_queue_rcu);
570 }
571
572 static const struct sysfs_ops queue_sysfs_ops = {
573         .show   = queue_attr_show,
574         .store  = queue_attr_store,
575 };
576
577 struct kobj_type blk_queue_ktype = {
578         .sysfs_ops      = &queue_sysfs_ops,
579         .default_attrs  = default_attrs,
580         .release        = blk_release_queue,
581 };
582
583 int blk_register_queue(struct gendisk *disk)
584 {
585         int ret;
586         struct device *dev = disk_to_dev(disk);
587         struct request_queue *q = disk->queue;
588
589         if (WARN_ON(!q))
590                 return -ENXIO;
591
592         /*
593          * SCSI probing may synchronously create and destroy a lot of
594          * request_queues for non-existent devices.  Shutting down a fully
595          * functional queue takes measureable wallclock time as RCU grace
596          * periods are involved.  To avoid excessive latency in these
597          * cases, a request_queue starts out in a degraded mode which is
598          * faster to shut down and is made fully functional here as
599          * request_queues for non-existent devices never get registered.
600          */
601         if (!blk_queue_init_done(q)) {
602                 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
603                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
604                 blk_queue_bypass_end(q);
605         }
606
607         ret = blk_trace_init_sysfs(dev);
608         if (ret)
609                 return ret;
610
611         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
612         if (ret < 0) {
613                 blk_trace_remove_sysfs(dev);
614                 return ret;
615         }
616
617         kobject_uevent(&q->kobj, KOBJ_ADD);
618
619         if (q->mq_ops)
620                 blk_mq_register_disk(disk);
621
622         if (!q->request_fn)
623                 return 0;
624
625         ret = elv_register_queue(q);
626         if (ret) {
627                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
628                 kobject_del(&q->kobj);
629                 blk_trace_remove_sysfs(dev);
630                 kobject_put(&dev->kobj);
631                 return ret;
632         }
633
634         return 0;
635 }
636
637 void blk_unregister_queue(struct gendisk *disk)
638 {
639         struct request_queue *q = disk->queue;
640
641         if (WARN_ON(!q))
642                 return;
643
644         if (q->mq_ops)
645                 blk_mq_unregister_disk(disk);
646
647         if (q->request_fn)
648                 elv_unregister_queue(q);
649
650         kobject_uevent(&q->kobj, KOBJ_REMOVE);
651         kobject_del(&q->kobj);
652         blk_trace_remove_sysfs(disk_to_dev(disk));
653         kobject_put(&disk_to_dev(disk)->kobj);
654 }