Root/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
13struct 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
19static ssize_t
20queue_var_show(unsigned long var, char *page)
21{
22    return sprintf(page, "%lu\n", var);
23}
24
25static ssize_t
26queue_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
34static ssize_t queue_requests_show(struct request_queue *q, char *page)
35{
36    return queue_var_show(q->nr_requests, (page));
37}
38
39static ssize_t
40queue_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 if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
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 if (rl->count[BLK_RW_ASYNC]+1 <= q->nr_requests) {
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
84static 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
92static ssize_t
93queue_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
103static 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
110static 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
115static 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
120static 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
128static 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
133static 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
138static 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
143static 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
148static 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
153static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
154{
155    return queue_var_show(q->limits.max_discard_sectors << 9, page);
156}
157
158static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
159{
160    return queue_var_show(queue_discard_zeroes_data(q), page);
161}
162
163static ssize_t
164queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
165{
166    unsigned long max_sectors_kb,
167        max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
168            page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
169    ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
170
171    if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
172        return -EINVAL;
173
174    spin_lock_irq(q->queue_lock);
175    q->limits.max_sectors = max_sectors_kb << 1;
176    spin_unlock_irq(q->queue_lock);
177
178    return ret;
179}
180
181static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
182{
183    int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
184
185    return queue_var_show(max_hw_sectors_kb, (page));
186}
187
188#define QUEUE_SYSFS_BIT_FNS(name, flag, neg) \
189static ssize_t \
190queue_show_##name(struct request_queue *q, char *page) \
191{ \
192    int bit; \
193    bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags); \
194    return queue_var_show(neg ? !bit : bit, page); \
195} \
196static ssize_t \
197queue_store_##name(struct request_queue *q, const char *page, size_t count) \
198{ \
199    unsigned long val; \
200    ssize_t ret; \
201    ret = queue_var_store(&val, page, count); \
202    if (neg) \
203        val = !val; \
204                                    \
205    spin_lock_irq(q->queue_lock); \
206    if (val) \
207        queue_flag_set(QUEUE_FLAG_##flag, q); \
208    else \
209        queue_flag_clear(QUEUE_FLAG_##flag, q); \
210    spin_unlock_irq(q->queue_lock); \
211    return ret; \
212}
213
214QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
215QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
216QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
217#undef QUEUE_SYSFS_BIT_FNS
218
219static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
220{
221    return queue_var_show((blk_queue_nomerges(q) << 1) |
222                   blk_queue_noxmerges(q), page);
223}
224
225static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
226                    size_t count)
227{
228    unsigned long nm;
229    ssize_t ret = queue_var_store(&nm, page, count);
230
231    spin_lock_irq(q->queue_lock);
232    queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
233    queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
234    if (nm == 2)
235        queue_flag_set(QUEUE_FLAG_NOMERGES, q);
236    else if (nm)
237        queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
238    spin_unlock_irq(q->queue_lock);
239
240    return ret;
241}
242
243static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
244{
245    bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
246
247    return queue_var_show(set, page);
248}
249
250static ssize_t
251queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
252{
253    ssize_t ret = -EINVAL;
254#if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
255    unsigned long val;
256
257    ret = queue_var_store(&val, page, count);
258    spin_lock_irq(q->queue_lock);
259    if (val)
260        queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
261    else
262        queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
263    spin_unlock_irq(q->queue_lock);
264#endif
265    return ret;
266}
267
268static struct queue_sysfs_entry queue_requests_entry = {
269    .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
270    .show = queue_requests_show,
271    .store = queue_requests_store,
272};
273
274static struct queue_sysfs_entry queue_ra_entry = {
275    .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
276    .show = queue_ra_show,
277    .store = queue_ra_store,
278};
279
280static struct queue_sysfs_entry queue_max_sectors_entry = {
281    .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
282    .show = queue_max_sectors_show,
283    .store = queue_max_sectors_store,
284};
285
286static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
287    .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
288    .show = queue_max_hw_sectors_show,
289};
290
291static struct queue_sysfs_entry queue_max_segments_entry = {
292    .attr = {.name = "max_segments", .mode = S_IRUGO },
293    .show = queue_max_segments_show,
294};
295
296static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
297    .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
298    .show = queue_max_integrity_segments_show,
299};
300
301static struct queue_sysfs_entry queue_max_segment_size_entry = {
302    .attr = {.name = "max_segment_size", .mode = S_IRUGO },
303    .show = queue_max_segment_size_show,
304};
305
306static struct queue_sysfs_entry queue_iosched_entry = {
307    .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
308    .show = elv_iosched_show,
309    .store = elv_iosched_store,
310};
311
312static struct queue_sysfs_entry queue_hw_sector_size_entry = {
313    .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
314    .show = queue_logical_block_size_show,
315};
316
317static struct queue_sysfs_entry queue_logical_block_size_entry = {
318    .attr = {.name = "logical_block_size", .mode = S_IRUGO },
319    .show = queue_logical_block_size_show,
320};
321
322static struct queue_sysfs_entry queue_physical_block_size_entry = {
323    .attr = {.name = "physical_block_size", .mode = S_IRUGO },
324    .show = queue_physical_block_size_show,
325};
326
327static struct queue_sysfs_entry queue_io_min_entry = {
328    .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
329    .show = queue_io_min_show,
330};
331
332static struct queue_sysfs_entry queue_io_opt_entry = {
333    .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
334    .show = queue_io_opt_show,
335};
336
337static struct queue_sysfs_entry queue_discard_granularity_entry = {
338    .attr = {.name = "discard_granularity", .mode = S_IRUGO },
339    .show = queue_discard_granularity_show,
340};
341
342static struct queue_sysfs_entry queue_discard_max_entry = {
343    .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
344    .show = queue_discard_max_show,
345};
346
347static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
348    .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
349    .show = queue_discard_zeroes_data_show,
350};
351
352static struct queue_sysfs_entry queue_nonrot_entry = {
353    .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
354    .show = queue_show_nonrot,
355    .store = queue_store_nonrot,
356};
357
358static struct queue_sysfs_entry queue_nomerges_entry = {
359    .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
360    .show = queue_nomerges_show,
361    .store = queue_nomerges_store,
362};
363
364static struct queue_sysfs_entry queue_rq_affinity_entry = {
365    .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
366    .show = queue_rq_affinity_show,
367    .store = queue_rq_affinity_store,
368};
369
370static struct queue_sysfs_entry queue_iostats_entry = {
371    .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
372    .show = queue_show_iostats,
373    .store = queue_store_iostats,
374};
375
376static struct queue_sysfs_entry queue_random_entry = {
377    .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
378    .show = queue_show_random,
379    .store = queue_store_random,
380};
381
382static struct attribute *default_attrs[] = {
383    &queue_requests_entry.attr,
384    &queue_ra_entry.attr,
385    &queue_max_hw_sectors_entry.attr,
386    &queue_max_sectors_entry.attr,
387    &queue_max_segments_entry.attr,
388    &queue_max_integrity_segments_entry.attr,
389    &queue_max_segment_size_entry.attr,
390    &queue_iosched_entry.attr,
391    &queue_hw_sector_size_entry.attr,
392    &queue_logical_block_size_entry.attr,
393    &queue_physical_block_size_entry.attr,
394    &queue_io_min_entry.attr,
395    &queue_io_opt_entry.attr,
396    &queue_discard_granularity_entry.attr,
397    &queue_discard_max_entry.attr,
398    &queue_discard_zeroes_data_entry.attr,
399    &queue_nonrot_entry.attr,
400    &queue_nomerges_entry.attr,
401    &queue_rq_affinity_entry.attr,
402    &queue_iostats_entry.attr,
403    &queue_random_entry.attr,
404    NULL,
405};
406
407#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
408
409static ssize_t
410queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
411{
412    struct queue_sysfs_entry *entry = to_queue(attr);
413    struct request_queue *q =
414        container_of(kobj, struct request_queue, kobj);
415    ssize_t res;
416
417    if (!entry->show)
418        return -EIO;
419    mutex_lock(&q->sysfs_lock);
420    if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
421        mutex_unlock(&q->sysfs_lock);
422        return -ENOENT;
423    }
424    res = entry->show(q, page);
425    mutex_unlock(&q->sysfs_lock);
426    return res;
427}
428
429static ssize_t
430queue_attr_store(struct kobject *kobj, struct attribute *attr,
431            const char *page, size_t length)
432{
433    struct queue_sysfs_entry *entry = to_queue(attr);
434    struct request_queue *q;
435    ssize_t res;
436
437    if (!entry->store)
438        return -EIO;
439
440    q = container_of(kobj, struct request_queue, kobj);
441    mutex_lock(&q->sysfs_lock);
442    if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
443        mutex_unlock(&q->sysfs_lock);
444        return -ENOENT;
445    }
446    res = entry->store(q, page, length);
447    mutex_unlock(&q->sysfs_lock);
448    return res;
449}
450
451/**
452 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
453 * @kobj: the kobj belonging of the request queue to be released
454 *
455 * Description:
456 * blk_cleanup_queue is the pair to blk_init_queue() or
457 * blk_queue_make_request(). It should be called when a request queue is
458 * being released; typically when a block device is being de-registered.
459 * Currently, its primary task it to free all the &struct request
460 * structures that were allocated to the queue and the queue itself.
461 *
462 * Caveat:
463 * Hopefully the low level driver will have finished any
464 * outstanding requests first...
465 **/
466static void blk_release_queue(struct kobject *kobj)
467{
468    struct request_queue *q =
469        container_of(kobj, struct request_queue, kobj);
470    struct request_list *rl = &q->rq;
471
472    blk_sync_queue(q);
473
474    blk_throtl_exit(q);
475
476    if (rl->rq_pool)
477        mempool_destroy(rl->rq_pool);
478
479    if (q->queue_tags)
480        __blk_queue_free_tags(q);
481
482    blk_trace_shutdown(q);
483
484    bdi_destroy(&q->backing_dev_info);
485    kmem_cache_free(blk_requestq_cachep, q);
486}
487
488static const struct sysfs_ops queue_sysfs_ops = {
489    .show = queue_attr_show,
490    .store = queue_attr_store,
491};
492
493struct kobj_type blk_queue_ktype = {
494    .sysfs_ops = &queue_sysfs_ops,
495    .default_attrs = default_attrs,
496    .release = blk_release_queue,
497};
498
499int blk_register_queue(struct gendisk *disk)
500{
501    int ret;
502    struct device *dev = disk_to_dev(disk);
503
504    struct request_queue *q = disk->queue;
505
506    if (WARN_ON(!q))
507        return -ENXIO;
508
509    ret = blk_trace_init_sysfs(dev);
510    if (ret)
511        return ret;
512
513    ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
514    if (ret < 0)
515        return ret;
516
517    kobject_uevent(&q->kobj, KOBJ_ADD);
518
519    if (!q->request_fn)
520        return 0;
521
522    ret = elv_register_queue(q);
523    if (ret) {
524        kobject_uevent(&q->kobj, KOBJ_REMOVE);
525        kobject_del(&q->kobj);
526        blk_trace_remove_sysfs(disk_to_dev(disk));
527        kobject_put(&dev->kobj);
528        return ret;
529    }
530
531    return 0;
532}
533
534void blk_unregister_queue(struct gendisk *disk)
535{
536    struct request_queue *q = disk->queue;
537
538    if (WARN_ON(!q))
539        return;
540
541    if (q->request_fn)
542        elv_unregister_queue(q);
543
544    kobject_uevent(&q->kobj, KOBJ_REMOVE);
545    kobject_del(&q->kobj);
546    blk_trace_remove_sysfs(disk_to_dev(disk));
547    kobject_put(&disk_to_dev(disk)->kobj);
548}
549

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