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
queue_var_show(unsigned long var,char * page)21 queue_var_show(unsigned long var, char *page)
22 {
23 return sprintf(page, "%lu\n", var);
24 }
25
26 static ssize_t
queue_var_store(unsigned long * var,const char * page,size_t count)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
queue_requests_show(struct request_queue * q,char * page)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
queue_requests_store(struct request_queue * q,const char * page,size_t count)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
queue_ra_show(struct request_queue * q,char * page)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
queue_ra_store(struct request_queue * q,const char * page,size_t count)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
queue_max_sectors_show(struct request_queue * q,char * page)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
queue_max_segments_show(struct request_queue * q,char * page)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
queue_max_integrity_segments_show(struct request_queue * q,char * page)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
queue_max_segment_size_show(struct request_queue * q,char * page)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
queue_logical_block_size_show(struct request_queue * q,char * page)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
queue_physical_block_size_show(struct request_queue * q,char * page)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
queue_io_min_show(struct request_queue * q,char * page)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
queue_io_opt_show(struct request_queue * q,char * page)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
queue_discard_granularity_show(struct request_queue * q,char * page)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
queue_discard_max_show(struct request_queue * q,char * page)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
queue_discard_zeroes_data_show(struct request_queue * q,char * page)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
queue_write_same_max_show(struct request_queue * q,char * page)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
queue_max_sectors_store(struct request_queue * q,const char * page,size_t count)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
queue_max_hw_sectors_show(struct request_queue * q,char * page)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 (ret < 0) \
233 return ret; \
234 if (neg) \
235 val = !val; \
236 \
237 spin_lock_irq(q->queue_lock); \
238 if (val) \
239 queue_flag_set(QUEUE_FLAG_##flag, q); \
240 else \
241 queue_flag_clear(QUEUE_FLAG_##flag, q); \
242 spin_unlock_irq(q->queue_lock); \
243 return ret; \
244 }
245
246 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
247 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
248 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
249 #undef QUEUE_SYSFS_BIT_FNS
250
queue_nomerges_show(struct request_queue * q,char * page)251 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
252 {
253 return queue_var_show((blk_queue_nomerges(q) << 1) |
254 blk_queue_noxmerges(q), page);
255 }
256
queue_nomerges_store(struct request_queue * q,const char * page,size_t count)257 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
258 size_t count)
259 {
260 unsigned long nm;
261 ssize_t ret = queue_var_store(&nm, page, count);
262
263 if (ret < 0)
264 return ret;
265
266 spin_lock_irq(q->queue_lock);
267 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
268 queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
269 if (nm == 2)
270 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
271 else if (nm)
272 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
273 spin_unlock_irq(q->queue_lock);
274
275 return ret;
276 }
277
queue_rq_affinity_show(struct request_queue * q,char * page)278 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
279 {
280 bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
281 bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
282
283 return queue_var_show(set << force, page);
284 }
285
286 static ssize_t
queue_rq_affinity_store(struct request_queue * q,const char * page,size_t count)287 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
288 {
289 ssize_t ret = -EINVAL;
290 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
291 unsigned long val;
292
293 ret = queue_var_store(&val, page, count);
294 if (ret < 0)
295 return ret;
296
297 spin_lock_irq(q->queue_lock);
298 if (val == 2) {
299 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
300 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
301 } else if (val == 1) {
302 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
303 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
304 } else if (val == 0) {
305 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
306 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
307 }
308 spin_unlock_irq(q->queue_lock);
309 #endif
310 return ret;
311 }
312
313 static struct queue_sysfs_entry queue_requests_entry = {
314 .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
315 .show = queue_requests_show,
316 .store = queue_requests_store,
317 };
318
319 static struct queue_sysfs_entry queue_ra_entry = {
320 .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
321 .show = queue_ra_show,
322 .store = queue_ra_store,
323 };
324
325 static struct queue_sysfs_entry queue_max_sectors_entry = {
326 .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
327 .show = queue_max_sectors_show,
328 .store = queue_max_sectors_store,
329 };
330
331 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
332 .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
333 .show = queue_max_hw_sectors_show,
334 };
335
336 static struct queue_sysfs_entry queue_max_segments_entry = {
337 .attr = {.name = "max_segments", .mode = S_IRUGO },
338 .show = queue_max_segments_show,
339 };
340
341 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
342 .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
343 .show = queue_max_integrity_segments_show,
344 };
345
346 static struct queue_sysfs_entry queue_max_segment_size_entry = {
347 .attr = {.name = "max_segment_size", .mode = S_IRUGO },
348 .show = queue_max_segment_size_show,
349 };
350
351 static struct queue_sysfs_entry queue_iosched_entry = {
352 .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
353 .show = elv_iosched_show,
354 .store = elv_iosched_store,
355 };
356
357 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
358 .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
359 .show = queue_logical_block_size_show,
360 };
361
362 static struct queue_sysfs_entry queue_logical_block_size_entry = {
363 .attr = {.name = "logical_block_size", .mode = S_IRUGO },
364 .show = queue_logical_block_size_show,
365 };
366
367 static struct queue_sysfs_entry queue_physical_block_size_entry = {
368 .attr = {.name = "physical_block_size", .mode = S_IRUGO },
369 .show = queue_physical_block_size_show,
370 };
371
372 static struct queue_sysfs_entry queue_io_min_entry = {
373 .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
374 .show = queue_io_min_show,
375 };
376
377 static struct queue_sysfs_entry queue_io_opt_entry = {
378 .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
379 .show = queue_io_opt_show,
380 };
381
382 static struct queue_sysfs_entry queue_discard_granularity_entry = {
383 .attr = {.name = "discard_granularity", .mode = S_IRUGO },
384 .show = queue_discard_granularity_show,
385 };
386
387 static struct queue_sysfs_entry queue_discard_max_entry = {
388 .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
389 .show = queue_discard_max_show,
390 };
391
392 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
393 .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
394 .show = queue_discard_zeroes_data_show,
395 };
396
397 static struct queue_sysfs_entry queue_write_same_max_entry = {
398 .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
399 .show = queue_write_same_max_show,
400 };
401
402 static struct queue_sysfs_entry queue_nonrot_entry = {
403 .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
404 .show = queue_show_nonrot,
405 .store = queue_store_nonrot,
406 };
407
408 static struct queue_sysfs_entry queue_nomerges_entry = {
409 .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
410 .show = queue_nomerges_show,
411 .store = queue_nomerges_store,
412 };
413
414 static struct queue_sysfs_entry queue_rq_affinity_entry = {
415 .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
416 .show = queue_rq_affinity_show,
417 .store = queue_rq_affinity_store,
418 };
419
420 static struct queue_sysfs_entry queue_iostats_entry = {
421 .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
422 .show = queue_show_iostats,
423 .store = queue_store_iostats,
424 };
425
426 static struct queue_sysfs_entry queue_random_entry = {
427 .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
428 .show = queue_show_random,
429 .store = queue_store_random,
430 };
431
432 static struct attribute *default_attrs[] = {
433 &queue_requests_entry.attr,
434 &queue_ra_entry.attr,
435 &queue_max_hw_sectors_entry.attr,
436 &queue_max_sectors_entry.attr,
437 &queue_max_segments_entry.attr,
438 &queue_max_integrity_segments_entry.attr,
439 &queue_max_segment_size_entry.attr,
440 &queue_iosched_entry.attr,
441 &queue_hw_sector_size_entry.attr,
442 &queue_logical_block_size_entry.attr,
443 &queue_physical_block_size_entry.attr,
444 &queue_io_min_entry.attr,
445 &queue_io_opt_entry.attr,
446 &queue_discard_granularity_entry.attr,
447 &queue_discard_max_entry.attr,
448 &queue_discard_zeroes_data_entry.attr,
449 &queue_write_same_max_entry.attr,
450 &queue_nonrot_entry.attr,
451 &queue_nomerges_entry.attr,
452 &queue_rq_affinity_entry.attr,
453 &queue_iostats_entry.attr,
454 &queue_random_entry.attr,
455 NULL,
456 };
457
458 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
459
460 static ssize_t
queue_attr_show(struct kobject * kobj,struct attribute * attr,char * page)461 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
462 {
463 struct queue_sysfs_entry *entry = to_queue(attr);
464 struct request_queue *q =
465 container_of(kobj, struct request_queue, kobj);
466 ssize_t res;
467
468 if (!entry->show)
469 return -EIO;
470 mutex_lock(&q->sysfs_lock);
471 if (blk_queue_dying(q)) {
472 mutex_unlock(&q->sysfs_lock);
473 return -ENOENT;
474 }
475 res = entry->show(q, page);
476 mutex_unlock(&q->sysfs_lock);
477 return res;
478 }
479
480 static ssize_t
queue_attr_store(struct kobject * kobj,struct attribute * attr,const char * page,size_t length)481 queue_attr_store(struct kobject *kobj, struct attribute *attr,
482 const char *page, size_t length)
483 {
484 struct queue_sysfs_entry *entry = to_queue(attr);
485 struct request_queue *q;
486 ssize_t res;
487
488 if (!entry->store)
489 return -EIO;
490
491 q = container_of(kobj, struct request_queue, kobj);
492 mutex_lock(&q->sysfs_lock);
493 if (blk_queue_dying(q)) {
494 mutex_unlock(&q->sysfs_lock);
495 return -ENOENT;
496 }
497 res = entry->store(q, page, length);
498 mutex_unlock(&q->sysfs_lock);
499 return res;
500 }
501
blk_free_queue_rcu(struct rcu_head * rcu_head)502 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
503 {
504 struct request_queue *q = container_of(rcu_head, struct request_queue,
505 rcu_head);
506 kmem_cache_free(blk_requestq_cachep, q);
507 }
508
509 /**
510 * blk_release_queue: - release a &struct request_queue when it is no longer needed
511 * @kobj: the kobj belonging to the request queue to be released
512 *
513 * Description:
514 * blk_release_queue is the pair to blk_init_queue() or
515 * blk_queue_make_request(). It should be called when a request queue is
516 * being released; typically when a block device is being de-registered.
517 * Currently, its primary task it to free all the &struct request
518 * structures that were allocated to the queue and the queue itself.
519 *
520 * Caveat:
521 * Hopefully the low level driver will have finished any
522 * outstanding requests first...
523 **/
blk_release_queue(struct kobject * kobj)524 static void blk_release_queue(struct kobject *kobj)
525 {
526 struct request_queue *q =
527 container_of(kobj, struct request_queue, kobj);
528
529 blk_sync_queue(q);
530
531 blkcg_exit_queue(q);
532
533 if (q->elevator) {
534 spin_lock_irq(q->queue_lock);
535 ioc_clear_queue(q);
536 spin_unlock_irq(q->queue_lock);
537 elevator_exit(q->elevator);
538 }
539
540 blk_exit_rl(&q->root_rl);
541
542 if (q->queue_tags)
543 __blk_queue_free_tags(q);
544
545 blk_trace_shutdown(q);
546
547 bdi_destroy(&q->backing_dev_info);
548
549 ida_simple_remove(&blk_queue_ida, q->id);
550 call_rcu(&q->rcu_head, blk_free_queue_rcu);
551 }
552
553 static const struct sysfs_ops queue_sysfs_ops = {
554 .show = queue_attr_show,
555 .store = queue_attr_store,
556 };
557
558 struct kobj_type blk_queue_ktype = {
559 .sysfs_ops = &queue_sysfs_ops,
560 .default_attrs = default_attrs,
561 .release = blk_release_queue,
562 };
563
blk_register_queue(struct gendisk * disk)564 int blk_register_queue(struct gendisk *disk)
565 {
566 int ret;
567 struct device *dev = disk_to_dev(disk);
568 struct request_queue *q = disk->queue;
569
570 if (WARN_ON(!q))
571 return -ENXIO;
572
573 /*
574 * Initialization must be complete by now. Finish the initial
575 * bypass from queue allocation.
576 */
577 blk_queue_bypass_end(q);
578
579 ret = blk_trace_init_sysfs(dev);
580 if (ret)
581 return ret;
582
583 ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
584 if (ret < 0) {
585 blk_trace_remove_sysfs(dev);
586 return ret;
587 }
588
589 kobject_uevent(&q->kobj, KOBJ_ADD);
590
591 if (!q->request_fn)
592 return 0;
593
594 ret = elv_register_queue(q);
595 if (ret) {
596 kobject_uevent(&q->kobj, KOBJ_REMOVE);
597 kobject_del(&q->kobj);
598 blk_trace_remove_sysfs(dev);
599 kobject_put(&dev->kobj);
600 return ret;
601 }
602
603 return 0;
604 }
605
blk_unregister_queue(struct gendisk * disk)606 void blk_unregister_queue(struct gendisk *disk)
607 {
608 struct request_queue *q = disk->queue;
609
610 if (WARN_ON(!q))
611 return;
612
613 if (q->request_fn)
614 elv_unregister_queue(q);
615
616 kobject_uevent(&q->kobj, KOBJ_REMOVE);
617 kobject_del(&q->kobj);
618 blk_trace_remove_sysfs(disk_to_dev(disk));
619 kobject_put(&disk_to_dev(disk)->kobj);
620 }
621