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Merge tag 'arc-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
[karo-tx-linux.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 #include <linux/blk-mq.h>
11
12 #include "blk.h"
13 #include "blk-cgroup.h"
14 #include "blk-mq.h"
15
16 struct queue_sysfs_entry {
17         struct attribute attr;
18         ssize_t (*show)(struct request_queue *, char *);
19         ssize_t (*store)(struct request_queue *, const char *, size_t);
20 };
21
22 static ssize_t
23 queue_var_show(unsigned long var, char *page)
24 {
25         return sprintf(page, "%lu\n", var);
26 }
27
28 static ssize_t
29 queue_var_store(unsigned long *var, const char *page, size_t count)
30 {
31         int err;
32         unsigned long v;
33
34         err = kstrtoul(page, 10, &v);
35         if (err || v > UINT_MAX)
36                 return -EINVAL;
37
38         *var = v;
39
40         return count;
41 }
42
43 static ssize_t queue_requests_show(struct request_queue *q, char *page)
44 {
45         return queue_var_show(q->nr_requests, (page));
46 }
47
48 static ssize_t
49 queue_requests_store(struct request_queue *q, const char *page, size_t count)
50 {
51         unsigned long nr;
52         int ret, err;
53
54         if (!q->request_fn && !q->mq_ops)
55                 return -EINVAL;
56
57         ret = queue_var_store(&nr, page, count);
58         if (ret < 0)
59                 return ret;
60
61         if (nr < BLKDEV_MIN_RQ)
62                 nr = BLKDEV_MIN_RQ;
63
64         if (q->request_fn)
65                 err = blk_update_nr_requests(q, nr);
66         else
67                 err = blk_mq_update_nr_requests(q, nr);
68
69         if (err)
70                 return err;
71
72         return ret;
73 }
74
75 static ssize_t queue_ra_show(struct request_queue *q, char *page)
76 {
77         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
78                                         (PAGE_CACHE_SHIFT - 10);
79
80         return queue_var_show(ra_kb, (page));
81 }
82
83 static ssize_t
84 queue_ra_store(struct request_queue *q, const char *page, size_t count)
85 {
86         unsigned long ra_kb;
87         ssize_t ret = queue_var_store(&ra_kb, page, count);
88
89         if (ret < 0)
90                 return ret;
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_max_segments_show(struct request_queue *q, char *page)
105 {
106         return queue_var_show(queue_max_segments(q), (page));
107 }
108
109 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
110 {
111         return queue_var_show(q->limits.max_integrity_segments, (page));
112 }
113
114 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
115 {
116         if (blk_queue_cluster(q))
117                 return queue_var_show(queue_max_segment_size(q), (page));
118
119         return queue_var_show(PAGE_CACHE_SIZE, (page));
120 }
121
122 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
123 {
124         return queue_var_show(queue_logical_block_size(q), page);
125 }
126
127 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
128 {
129         return queue_var_show(queue_physical_block_size(q), page);
130 }
131
132 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
133 {
134         return queue_var_show(queue_io_min(q), page);
135 }
136
137 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
138 {
139         return queue_var_show(queue_io_opt(q), page);
140 }
141
142 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
143 {
144         return queue_var_show(q->limits.discard_granularity, page);
145 }
146
147 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
148 {
149         return sprintf(page, "%llu\n",
150                        (unsigned long long)q->limits.max_discard_sectors << 9);
151 }
152
153 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
154 {
155         return queue_var_show(queue_discard_zeroes_data(q), page);
156 }
157
158 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
159 {
160         return sprintf(page, "%llu\n",
161                 (unsigned long long)q->limits.max_write_same_sectors << 9);
162 }
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 (ret < 0)
174                 return ret;
175
176         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
177                 return -EINVAL;
178
179         spin_lock_irq(q->queue_lock);
180         q->limits.max_sectors = max_sectors_kb << 1;
181         spin_unlock_irq(q->queue_lock);
182
183         return ret;
184 }
185
186 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
187 {
188         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
189
190         return queue_var_show(max_hw_sectors_kb, (page));
191 }
192
193 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
194 static ssize_t                                                          \
195 queue_show_##name(struct request_queue *q, char *page)                  \
196 {                                                                       \
197         int bit;                                                        \
198         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
199         return queue_var_show(neg ? !bit : bit, page);                  \
200 }                                                                       \
201 static ssize_t                                                          \
202 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
203 {                                                                       \
204         unsigned long val;                                              \
205         ssize_t ret;                                                    \
206         ret = queue_var_store(&val, page, count);                       \
207         if (ret < 0)                                                    \
208                  return ret;                                            \
209         if (neg)                                                        \
210                 val = !val;                                             \
211                                                                         \
212         spin_lock_irq(q->queue_lock);                                   \
213         if (val)                                                        \
214                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
215         else                                                            \
216                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
217         spin_unlock_irq(q->queue_lock);                                 \
218         return ret;                                                     \
219 }
220
221 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
222 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
223 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
224 #undef QUEUE_SYSFS_BIT_FNS
225
226 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
227 {
228         return queue_var_show((blk_queue_nomerges(q) << 1) |
229                                blk_queue_noxmerges(q), page);
230 }
231
232 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
233                                     size_t count)
234 {
235         unsigned long nm;
236         ssize_t ret = queue_var_store(&nm, page, count);
237
238         if (ret < 0)
239                 return ret;
240
241         spin_lock_irq(q->queue_lock);
242         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
243         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
244         if (nm == 2)
245                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
246         else if (nm)
247                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
248         spin_unlock_irq(q->queue_lock);
249
250         return ret;
251 }
252
253 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
254 {
255         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
256         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
257
258         return queue_var_show(set << force, page);
259 }
260
261 static ssize_t
262 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
263 {
264         ssize_t ret = -EINVAL;
265 #ifdef CONFIG_SMP
266         unsigned long val;
267
268         ret = queue_var_store(&val, page, count);
269         if (ret < 0)
270                 return ret;
271
272         spin_lock_irq(q->queue_lock);
273         if (val == 2) {
274                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
275                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
276         } else if (val == 1) {
277                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
278                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
279         } else if (val == 0) {
280                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
281                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
282         }
283         spin_unlock_irq(q->queue_lock);
284 #endif
285         return ret;
286 }
287
288 static struct queue_sysfs_entry queue_requests_entry = {
289         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
290         .show = queue_requests_show,
291         .store = queue_requests_store,
292 };
293
294 static struct queue_sysfs_entry queue_ra_entry = {
295         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
296         .show = queue_ra_show,
297         .store = queue_ra_store,
298 };
299
300 static struct queue_sysfs_entry queue_max_sectors_entry = {
301         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
302         .show = queue_max_sectors_show,
303         .store = queue_max_sectors_store,
304 };
305
306 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
307         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
308         .show = queue_max_hw_sectors_show,
309 };
310
311 static struct queue_sysfs_entry queue_max_segments_entry = {
312         .attr = {.name = "max_segments", .mode = S_IRUGO },
313         .show = queue_max_segments_show,
314 };
315
316 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
317         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
318         .show = queue_max_integrity_segments_show,
319 };
320
321 static struct queue_sysfs_entry queue_max_segment_size_entry = {
322         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
323         .show = queue_max_segment_size_show,
324 };
325
326 static struct queue_sysfs_entry queue_iosched_entry = {
327         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
328         .show = elv_iosched_show,
329         .store = elv_iosched_store,
330 };
331
332 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
333         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
334         .show = queue_logical_block_size_show,
335 };
336
337 static struct queue_sysfs_entry queue_logical_block_size_entry = {
338         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
339         .show = queue_logical_block_size_show,
340 };
341
342 static struct queue_sysfs_entry queue_physical_block_size_entry = {
343         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
344         .show = queue_physical_block_size_show,
345 };
346
347 static struct queue_sysfs_entry queue_io_min_entry = {
348         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
349         .show = queue_io_min_show,
350 };
351
352 static struct queue_sysfs_entry queue_io_opt_entry = {
353         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
354         .show = queue_io_opt_show,
355 };
356
357 static struct queue_sysfs_entry queue_discard_granularity_entry = {
358         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
359         .show = queue_discard_granularity_show,
360 };
361
362 static struct queue_sysfs_entry queue_discard_max_entry = {
363         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
364         .show = queue_discard_max_show,
365 };
366
367 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
368         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
369         .show = queue_discard_zeroes_data_show,
370 };
371
372 static struct queue_sysfs_entry queue_write_same_max_entry = {
373         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
374         .show = queue_write_same_max_show,
375 };
376
377 static struct queue_sysfs_entry queue_nonrot_entry = {
378         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
379         .show = queue_show_nonrot,
380         .store = queue_store_nonrot,
381 };
382
383 static struct queue_sysfs_entry queue_nomerges_entry = {
384         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
385         .show = queue_nomerges_show,
386         .store = queue_nomerges_store,
387 };
388
389 static struct queue_sysfs_entry queue_rq_affinity_entry = {
390         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
391         .show = queue_rq_affinity_show,
392         .store = queue_rq_affinity_store,
393 };
394
395 static struct queue_sysfs_entry queue_iostats_entry = {
396         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
397         .show = queue_show_iostats,
398         .store = queue_store_iostats,
399 };
400
401 static struct queue_sysfs_entry queue_random_entry = {
402         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
403         .show = queue_show_random,
404         .store = queue_store_random,
405 };
406
407 static struct attribute *default_attrs[] = {
408         &queue_requests_entry.attr,
409         &queue_ra_entry.attr,
410         &queue_max_hw_sectors_entry.attr,
411         &queue_max_sectors_entry.attr,
412         &queue_max_segments_entry.attr,
413         &queue_max_integrity_segments_entry.attr,
414         &queue_max_segment_size_entry.attr,
415         &queue_iosched_entry.attr,
416         &queue_hw_sector_size_entry.attr,
417         &queue_logical_block_size_entry.attr,
418         &queue_physical_block_size_entry.attr,
419         &queue_io_min_entry.attr,
420         &queue_io_opt_entry.attr,
421         &queue_discard_granularity_entry.attr,
422         &queue_discard_max_entry.attr,
423         &queue_discard_zeroes_data_entry.attr,
424         &queue_write_same_max_entry.attr,
425         &queue_nonrot_entry.attr,
426         &queue_nomerges_entry.attr,
427         &queue_rq_affinity_entry.attr,
428         &queue_iostats_entry.attr,
429         &queue_random_entry.attr,
430         NULL,
431 };
432
433 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
434
435 static ssize_t
436 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
437 {
438         struct queue_sysfs_entry *entry = to_queue(attr);
439         struct request_queue *q =
440                 container_of(kobj, struct request_queue, kobj);
441         ssize_t res;
442
443         if (!entry->show)
444                 return -EIO;
445         mutex_lock(&q->sysfs_lock);
446         if (blk_queue_dying(q)) {
447                 mutex_unlock(&q->sysfs_lock);
448                 return -ENOENT;
449         }
450         res = entry->show(q, page);
451         mutex_unlock(&q->sysfs_lock);
452         return res;
453 }
454
455 static ssize_t
456 queue_attr_store(struct kobject *kobj, struct attribute *attr,
457                     const char *page, size_t length)
458 {
459         struct queue_sysfs_entry *entry = to_queue(attr);
460         struct request_queue *q;
461         ssize_t res;
462
463         if (!entry->store)
464                 return -EIO;
465
466         q = container_of(kobj, struct request_queue, kobj);
467         mutex_lock(&q->sysfs_lock);
468         if (blk_queue_dying(q)) {
469                 mutex_unlock(&q->sysfs_lock);
470                 return -ENOENT;
471         }
472         res = entry->store(q, page, length);
473         mutex_unlock(&q->sysfs_lock);
474         return res;
475 }
476
477 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
478 {
479         struct request_queue *q = container_of(rcu_head, struct request_queue,
480                                                rcu_head);
481         kmem_cache_free(blk_requestq_cachep, q);
482 }
483
484 /**
485  * blk_release_queue: - release a &struct request_queue when it is no longer needed
486  * @kobj:    the kobj belonging to the request queue to be released
487  *
488  * Description:
489  *     blk_release_queue is the pair to blk_init_queue() or
490  *     blk_queue_make_request().  It should be called when a request queue is
491  *     being released; typically when a block device is being de-registered.
492  *     Currently, its primary task it to free all the &struct request
493  *     structures that were allocated to the queue and the queue itself.
494  *
495  * Note:
496  *     The low level driver must have finished any outstanding requests first
497  *     via blk_cleanup_queue().
498  **/
499 static void blk_release_queue(struct kobject *kobj)
500 {
501         struct request_queue *q =
502                 container_of(kobj, struct request_queue, kobj);
503
504         blkcg_exit_queue(q);
505
506         if (q->elevator) {
507                 spin_lock_irq(q->queue_lock);
508                 ioc_clear_queue(q);
509                 spin_unlock_irq(q->queue_lock);
510                 elevator_exit(q->elevator);
511         }
512
513         blk_exit_rl(&q->root_rl);
514
515         if (q->queue_tags)
516                 __blk_queue_free_tags(q);
517
518         if (!q->mq_ops)
519                 blk_free_flush_queue(q->fq);
520         else
521                 blk_mq_release(q);
522
523         blk_trace_shutdown(q);
524
525         bdi_destroy(&q->backing_dev_info);
526
527         ida_simple_remove(&blk_queue_ida, q->id);
528         call_rcu(&q->rcu_head, blk_free_queue_rcu);
529 }
530
531 static const struct sysfs_ops queue_sysfs_ops = {
532         .show   = queue_attr_show,
533         .store  = queue_attr_store,
534 };
535
536 struct kobj_type blk_queue_ktype = {
537         .sysfs_ops      = &queue_sysfs_ops,
538         .default_attrs  = default_attrs,
539         .release        = blk_release_queue,
540 };
541
542 int blk_register_queue(struct gendisk *disk)
543 {
544         int ret;
545         struct device *dev = disk_to_dev(disk);
546         struct request_queue *q = disk->queue;
547
548         if (WARN_ON(!q))
549                 return -ENXIO;
550
551         /*
552          * SCSI probing may synchronously create and destroy a lot of
553          * request_queues for non-existent devices.  Shutting down a fully
554          * functional queue takes measureable wallclock time as RCU grace
555          * periods are involved.  To avoid excessive latency in these
556          * cases, a request_queue starts out in a degraded mode which is
557          * faster to shut down and is made fully functional here as
558          * request_queues for non-existent devices never get registered.
559          */
560         if (!blk_queue_init_done(q)) {
561                 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
562                 blk_queue_bypass_end(q);
563                 if (q->mq_ops)
564                         blk_mq_finish_init(q);
565         }
566
567         ret = blk_trace_init_sysfs(dev);
568         if (ret)
569                 return ret;
570
571         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
572         if (ret < 0) {
573                 blk_trace_remove_sysfs(dev);
574                 return ret;
575         }
576
577         kobject_uevent(&q->kobj, KOBJ_ADD);
578
579         if (q->mq_ops)
580                 blk_mq_register_disk(disk);
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->mq_ops)
605                 blk_mq_unregister_disk(disk);
606
607         if (q->request_fn)
608                 elv_unregister_queue(q);
609
610         kobject_uevent(&q->kobj, KOBJ_REMOVE);
611         kobject_del(&q->kobj);
612         blk_trace_remove_sysfs(disk_to_dev(disk));
613         kobject_put(&disk_to_dev(disk)->kobj);
614 }