xref: /openbmc/linux/block/blk-sysfs.c (revision 63dc02bd) 
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 
13 struct queue_sysfs_entry {
14 	struct attribute attr;
15 	ssize_t (*show)(struct request_queue *, char *);
16 	ssize_t (*store)(struct request_queue *, const char *, size_t);
17 };
18 
19 static ssize_t
20 queue_var_show(unsigned long var, char *page)
21 {
22 	return sprintf(page, "%lu\n", var);
23 }
24 
25 static ssize_t
26 queue_var_store(unsigned long *var, const char *page, size_t count)
27 {
28 	char *p = (char *) page;
29 
30 	*var = simple_strtoul(p, &p, 10);
31 	return count;
32 }
33 
34 static ssize_t queue_requests_show(struct request_queue *q, char *page)
35 {
36 	return queue_var_show(q->nr_requests, (page));
37 }
38 
39 static ssize_t
40 queue_requests_store(struct request_queue *q, const char *page, size_t count)
41 {
42 	struct request_list *rl = &q->rq;
43 	unsigned long nr;
44 	int ret;
45 
46 	if (!q->request_fn)
47 		return -EINVAL;
48 
49 	ret = queue_var_store(&nr, page, count);
50 	if (nr < BLKDEV_MIN_RQ)
51 		nr = BLKDEV_MIN_RQ;
52 
53 	spin_lock_irq(q->queue_lock);
54 	q->nr_requests = nr;
55 	blk_queue_congestion_threshold(q);
56 
57 	if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
58 		blk_set_queue_congested(q, BLK_RW_SYNC);
59 	else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
60 		blk_clear_queue_congested(q, BLK_RW_SYNC);
61 
62 	if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
63 		blk_set_queue_congested(q, BLK_RW_ASYNC);
64 	else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
65 		blk_clear_queue_congested(q, BLK_RW_ASYNC);
66 
67 	if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
68 		blk_set_queue_full(q, BLK_RW_SYNC);
69 	} else {
70 		blk_clear_queue_full(q, BLK_RW_SYNC);
71 		wake_up(&rl->wait[BLK_RW_SYNC]);
72 	}
73 
74 	if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
75 		blk_set_queue_full(q, BLK_RW_ASYNC);
76 	} else {
77 		blk_clear_queue_full(q, BLK_RW_ASYNC);
78 		wake_up(&rl->wait[BLK_RW_ASYNC]);
79 	}
80 	spin_unlock_irq(q->queue_lock);
81 	return ret;
82 }
83 
84 static ssize_t queue_ra_show(struct request_queue *q, char *page)
85 {
86 	unsigned long ra_kb = q->backing_dev_info.ra_pages <<
87 					(PAGE_CACHE_SHIFT - 10);
88 
89 	return queue_var_show(ra_kb, (page));
90 }
91 
92 static ssize_t
93 queue_ra_store(struct request_queue *q, const char *page, size_t count)
94 {
95 	unsigned long ra_kb;
96 	ssize_t ret = queue_var_store(&ra_kb, page, count);
97 
98 	q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
99 
100 	return ret;
101 }
102 
103 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
104 {
105 	int max_sectors_kb = queue_max_sectors(q) >> 1;
106 
107 	return queue_var_show(max_sectors_kb, (page));
108 }
109 
110 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
111 {
112 	return queue_var_show(queue_max_segments(q), (page));
113 }
114 
115 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
116 {
117 	return queue_var_show(q->limits.max_integrity_segments, (page));
118 }
119 
120 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
121 {
122 	if (blk_queue_cluster(q))
123 		return queue_var_show(queue_max_segment_size(q), (page));
124 
125 	return queue_var_show(PAGE_CACHE_SIZE, (page));
126 }
127 
128 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
129 {
130 	return queue_var_show(queue_logical_block_size(q), page);
131 }
132 
133 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
134 {
135 	return queue_var_show(queue_physical_block_size(q), page);
136 }
137 
138 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
139 {
140 	return queue_var_show(queue_io_min(q), page);
141 }
142 
143 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
144 {
145 	return queue_var_show(queue_io_opt(q), page);
146 }
147 
148 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
149 {
150 	return queue_var_show(q->limits.discard_granularity, page);
151 }
152 
153 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
154 {
155 	return sprintf(page, "%llu\n",
156 		       (unsigned long long)q->limits.max_discard_sectors << 9);
157 }
158 
159 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
160 {
161 	return queue_var_show(queue_discard_zeroes_data(q), page);
162 }
163 
164 static ssize_t
165 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
166 {
167 	unsigned long max_sectors_kb,
168 		max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
169 			page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
170 	ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
171 
172 	if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
173 		return -EINVAL;
174 
175 	spin_lock_irq(q->queue_lock);
176 	q->limits.max_sectors = max_sectors_kb << 1;
177 	spin_unlock_irq(q->queue_lock);
178 
179 	return ret;
180 }
181 
182 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
183 {
184 	int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
185 
186 	return queue_var_show(max_hw_sectors_kb, (page));
187 }
188 
189 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)				\
190 static ssize_t								\
191 queue_show_##name(struct request_queue *q, char *page)			\
192 {									\
193 	int bit;							\
194 	bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);		\
195 	return queue_var_show(neg ? !bit : bit, page);			\
196 }									\
197 static ssize_t								\
198 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
199 {									\
200 	unsigned long val;						\
201 	ssize_t ret;							\
202 	ret = queue_var_store(&val, page, count);			\
203 	if (neg)							\
204 		val = !val;						\
205 									\
206 	spin_lock_irq(q->queue_lock);					\
207 	if (val)							\
208 		queue_flag_set(QUEUE_FLAG_##flag, q);			\
209 	else								\
210 		queue_flag_clear(QUEUE_FLAG_##flag, q);			\
211 	spin_unlock_irq(q->queue_lock);					\
212 	return ret;							\
213 }
214 
215 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
216 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
217 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
218 #undef QUEUE_SYSFS_BIT_FNS
219 
220 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
221 {
222 	return queue_var_show((blk_queue_nomerges(q) << 1) |
223 			       blk_queue_noxmerges(q), page);
224 }
225 
226 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
227 				    size_t count)
228 {
229 	unsigned long nm;
230 	ssize_t ret = queue_var_store(&nm, page, count);
231 
232 	spin_lock_irq(q->queue_lock);
233 	queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
234 	queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
235 	if (nm == 2)
236 		queue_flag_set(QUEUE_FLAG_NOMERGES, q);
237 	else if (nm)
238 		queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
239 	spin_unlock_irq(q->queue_lock);
240 
241 	return ret;
242 }
243 
244 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
245 {
246 	bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
247 	bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
248 
249 	return queue_var_show(set << force, page);
250 }
251 
252 static ssize_t
253 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
254 {
255 	ssize_t ret = -EINVAL;
256 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
257 	unsigned long val;
258 
259 	ret = queue_var_store(&val, page, count);
260 	spin_lock_irq(q->queue_lock);
261 	if (val == 2) {
262 		queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
263 		queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
264 	} else if (val == 1) {
265 		queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
266 		queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
267 	} else if (val == 0) {
268 		queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
269 		queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
270 	}
271 	spin_unlock_irq(q->queue_lock);
272 #endif
273 	return ret;
274 }
275 
276 static struct queue_sysfs_entry queue_requests_entry = {
277 	.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
278 	.show = queue_requests_show,
279 	.store = queue_requests_store,
280 };
281 
282 static struct queue_sysfs_entry queue_ra_entry = {
283 	.attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
284 	.show = queue_ra_show,
285 	.store = queue_ra_store,
286 };
287 
288 static struct queue_sysfs_entry queue_max_sectors_entry = {
289 	.attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
290 	.show = queue_max_sectors_show,
291 	.store = queue_max_sectors_store,
292 };
293 
294 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
295 	.attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
296 	.show = queue_max_hw_sectors_show,
297 };
298 
299 static struct queue_sysfs_entry queue_max_segments_entry = {
300 	.attr = {.name = "max_segments", .mode = S_IRUGO },
301 	.show = queue_max_segments_show,
302 };
303 
304 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
305 	.attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
306 	.show = queue_max_integrity_segments_show,
307 };
308 
309 static struct queue_sysfs_entry queue_max_segment_size_entry = {
310 	.attr = {.name = "max_segment_size", .mode = S_IRUGO },
311 	.show = queue_max_segment_size_show,
312 };
313 
314 static struct queue_sysfs_entry queue_iosched_entry = {
315 	.attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
316 	.show = elv_iosched_show,
317 	.store = elv_iosched_store,
318 };
319 
320 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
321 	.attr = {.name = "hw_sector_size", .mode = S_IRUGO },
322 	.show = queue_logical_block_size_show,
323 };
324 
325 static struct queue_sysfs_entry queue_logical_block_size_entry = {
326 	.attr = {.name = "logical_block_size", .mode = S_IRUGO },
327 	.show = queue_logical_block_size_show,
328 };
329 
330 static struct queue_sysfs_entry queue_physical_block_size_entry = {
331 	.attr = {.name = "physical_block_size", .mode = S_IRUGO },
332 	.show = queue_physical_block_size_show,
333 };
334 
335 static struct queue_sysfs_entry queue_io_min_entry = {
336 	.attr = {.name = "minimum_io_size", .mode = S_IRUGO },
337 	.show = queue_io_min_show,
338 };
339 
340 static struct queue_sysfs_entry queue_io_opt_entry = {
341 	.attr = {.name = "optimal_io_size", .mode = S_IRUGO },
342 	.show = queue_io_opt_show,
343 };
344 
345 static struct queue_sysfs_entry queue_discard_granularity_entry = {
346 	.attr = {.name = "discard_granularity", .mode = S_IRUGO },
347 	.show = queue_discard_granularity_show,
348 };
349 
350 static struct queue_sysfs_entry queue_discard_max_entry = {
351 	.attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
352 	.show = queue_discard_max_show,
353 };
354 
355 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
356 	.attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
357 	.show = queue_discard_zeroes_data_show,
358 };
359 
360 static struct queue_sysfs_entry queue_nonrot_entry = {
361 	.attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
362 	.show = queue_show_nonrot,
363 	.store = queue_store_nonrot,
364 };
365 
366 static struct queue_sysfs_entry queue_nomerges_entry = {
367 	.attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
368 	.show = queue_nomerges_show,
369 	.store = queue_nomerges_store,
370 };
371 
372 static struct queue_sysfs_entry queue_rq_affinity_entry = {
373 	.attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
374 	.show = queue_rq_affinity_show,
375 	.store = queue_rq_affinity_store,
376 };
377 
378 static struct queue_sysfs_entry queue_iostats_entry = {
379 	.attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
380 	.show = queue_show_iostats,
381 	.store = queue_store_iostats,
382 };
383 
384 static struct queue_sysfs_entry queue_random_entry = {
385 	.attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
386 	.show = queue_show_random,
387 	.store = queue_store_random,
388 };
389 
390 static struct attribute *default_attrs[] = {
391 	&queue_requests_entry.attr,
392 	&queue_ra_entry.attr,
393 	&queue_max_hw_sectors_entry.attr,
394 	&queue_max_sectors_entry.attr,
395 	&queue_max_segments_entry.attr,
396 	&queue_max_integrity_segments_entry.attr,
397 	&queue_max_segment_size_entry.attr,
398 	&queue_iosched_entry.attr,
399 	&queue_hw_sector_size_entry.attr,
400 	&queue_logical_block_size_entry.attr,
401 	&queue_physical_block_size_entry.attr,
402 	&queue_io_min_entry.attr,
403 	&queue_io_opt_entry.attr,
404 	&queue_discard_granularity_entry.attr,
405 	&queue_discard_max_entry.attr,
406 	&queue_discard_zeroes_data_entry.attr,
407 	&queue_nonrot_entry.attr,
408 	&queue_nomerges_entry.attr,
409 	&queue_rq_affinity_entry.attr,
410 	&queue_iostats_entry.attr,
411 	&queue_random_entry.attr,
412 	NULL,
413 };
414 
415 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
416 
417 static ssize_t
418 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
419 {
420 	struct queue_sysfs_entry *entry = to_queue(attr);
421 	struct request_queue *q =
422 		container_of(kobj, struct request_queue, kobj);
423 	ssize_t res;
424 
425 	if (!entry->show)
426 		return -EIO;
427 	mutex_lock(&q->sysfs_lock);
428 	if (blk_queue_dead(q)) {
429 		mutex_unlock(&q->sysfs_lock);
430 		return -ENOENT;
431 	}
432 	res = entry->show(q, page);
433 	mutex_unlock(&q->sysfs_lock);
434 	return res;
435 }
436 
437 static ssize_t
438 queue_attr_store(struct kobject *kobj, struct attribute *attr,
439 		    const char *page, size_t length)
440 {
441 	struct queue_sysfs_entry *entry = to_queue(attr);
442 	struct request_queue *q;
443 	ssize_t res;
444 
445 	if (!entry->store)
446 		return -EIO;
447 
448 	q = container_of(kobj, struct request_queue, kobj);
449 	mutex_lock(&q->sysfs_lock);
450 	if (blk_queue_dead(q)) {
451 		mutex_unlock(&q->sysfs_lock);
452 		return -ENOENT;
453 	}
454 	res = entry->store(q, page, length);
455 	mutex_unlock(&q->sysfs_lock);
456 	return res;
457 }
458 
459 /**
460  * blk_release_queue: - release a &struct request_queue when it is no longer needed
461  * @kobj:    the kobj belonging to the request queue to be released
462  *
463  * Description:
464  *     blk_release_queue is the pair to blk_init_queue() or
465  *     blk_queue_make_request().  It should be called when a request queue is
466  *     being released; typically when a block device is being de-registered.
467  *     Currently, its primary task it to free all the &struct request
468  *     structures that were allocated to the queue and the queue itself.
469  *
470  * Caveat:
471  *     Hopefully the low level driver will have finished any
472  *     outstanding requests first...
473  **/
474 static void blk_release_queue(struct kobject *kobj)
475 {
476 	struct request_queue *q =
477 		container_of(kobj, struct request_queue, kobj);
478 	struct request_list *rl = &q->rq;
479 
480 	blk_sync_queue(q);
481 
482 	if (q->elevator) {
483 		spin_lock_irq(q->queue_lock);
484 		ioc_clear_queue(q);
485 		spin_unlock_irq(q->queue_lock);
486 		elevator_exit(q->elevator);
487 	}
488 
489 	blk_throtl_exit(q);
490 
491 	if (rl->rq_pool)
492 		mempool_destroy(rl->rq_pool);
493 
494 	if (q->queue_tags)
495 		__blk_queue_free_tags(q);
496 
497 	blk_throtl_release(q);
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 }
568