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_segment_size_show(struct request_queue *q, char *page)
116{
117    if (test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
118        return queue_var_show(queue_max_segment_size(q), (page));
119
120    return queue_var_show(PAGE_CACHE_SIZE, (page));
121}
122
123static 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
128static 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
133static 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
138static 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
143static 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
148static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
149{
150    return queue_var_show(q->limits.max_discard_sectors << 9, page);
151}
152
153static 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
158static ssize_t
159queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
160{
161    unsigned long max_sectors_kb,
162        max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
163            page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
164    ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
165
166    if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
167        return -EINVAL;
168
169    spin_lock_irq(q->queue_lock);
170    q->limits.max_sectors = max_sectors_kb << 1;
171    spin_unlock_irq(q->queue_lock);
172
173    return ret;
174}
175
176static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
177{
178    int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
179
180    return queue_var_show(max_hw_sectors_kb, (page));
181}
182
183static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
184{
185    return queue_var_show(!blk_queue_nonrot(q), page);
186}
187
188static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
189                  size_t count)
190{
191    unsigned long nm;
192    ssize_t ret = queue_var_store(&nm, page, count);
193
194    spin_lock_irq(q->queue_lock);
195    if (nm)
196        queue_flag_clear(QUEUE_FLAG_NONROT, q);
197    else
198        queue_flag_set(QUEUE_FLAG_NONROT, q);
199    spin_unlock_irq(q->queue_lock);
200
201    return ret;
202}
203
204static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
205{
206    return queue_var_show((blk_queue_nomerges(q) << 1) |
207                   blk_queue_noxmerges(q), page);
208}
209
210static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
211                    size_t count)
212{
213    unsigned long nm;
214    ssize_t ret = queue_var_store(&nm, page, count);
215
216    spin_lock_irq(q->queue_lock);
217    queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
218    queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
219    if (nm == 2)
220        queue_flag_set(QUEUE_FLAG_NOMERGES, q);
221    else if (nm)
222        queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
223    spin_unlock_irq(q->queue_lock);
224
225    return ret;
226}
227
228static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
229{
230    bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
231
232    return queue_var_show(set, page);
233}
234
235static ssize_t
236queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
237{
238    ssize_t ret = -EINVAL;
239#if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
240    unsigned long val;
241
242    ret = queue_var_store(&val, page, count);
243    spin_lock_irq(q->queue_lock);
244    if (val)
245        queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
246    else
247        queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
248    spin_unlock_irq(q->queue_lock);
249#endif
250    return ret;
251}
252
253static ssize_t queue_iostats_show(struct request_queue *q, char *page)
254{
255    return queue_var_show(blk_queue_io_stat(q), page);
256}
257
258static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
259                   size_t count)
260{
261    unsigned long stats;
262    ssize_t ret = queue_var_store(&stats, page, count);
263
264    spin_lock_irq(q->queue_lock);
265    if (stats)
266        queue_flag_set(QUEUE_FLAG_IO_STAT, q);
267    else
268        queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
269    spin_unlock_irq(q->queue_lock);
270
271    return ret;
272}
273
274static struct queue_sysfs_entry queue_requests_entry = {
275    .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
276    .show = queue_requests_show,
277    .store = queue_requests_store,
278};
279
280static struct queue_sysfs_entry queue_ra_entry = {
281    .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
282    .show = queue_ra_show,
283    .store = queue_ra_store,
284};
285
286static struct queue_sysfs_entry queue_max_sectors_entry = {
287    .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
288    .show = queue_max_sectors_show,
289    .store = queue_max_sectors_store,
290};
291
292static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
293    .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
294    .show = queue_max_hw_sectors_show,
295};
296
297static struct queue_sysfs_entry queue_max_segments_entry = {
298    .attr = {.name = "max_segments", .mode = S_IRUGO },
299    .show = queue_max_segments_show,
300};
301
302static struct queue_sysfs_entry queue_max_segment_size_entry = {
303    .attr = {.name = "max_segment_size", .mode = S_IRUGO },
304    .show = queue_max_segment_size_show,
305};
306
307static struct queue_sysfs_entry queue_iosched_entry = {
308    .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
309    .show = elv_iosched_show,
310    .store = elv_iosched_store,
311};
312
313static struct queue_sysfs_entry queue_hw_sector_size_entry = {
314    .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
315    .show = queue_logical_block_size_show,
316};
317
318static struct queue_sysfs_entry queue_logical_block_size_entry = {
319    .attr = {.name = "logical_block_size", .mode = S_IRUGO },
320    .show = queue_logical_block_size_show,
321};
322
323static struct queue_sysfs_entry queue_physical_block_size_entry = {
324    .attr = {.name = "physical_block_size", .mode = S_IRUGO },
325    .show = queue_physical_block_size_show,
326};
327
328static struct queue_sysfs_entry queue_io_min_entry = {
329    .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
330    .show = queue_io_min_show,
331};
332
333static struct queue_sysfs_entry queue_io_opt_entry = {
334    .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
335    .show = queue_io_opt_show,
336};
337
338static struct queue_sysfs_entry queue_discard_granularity_entry = {
339    .attr = {.name = "discard_granularity", .mode = S_IRUGO },
340    .show = queue_discard_granularity_show,
341};
342
343static struct queue_sysfs_entry queue_discard_max_entry = {
344    .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
345    .show = queue_discard_max_show,
346};
347
348static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
349    .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
350    .show = queue_discard_zeroes_data_show,
351};
352
353static struct queue_sysfs_entry queue_nonrot_entry = {
354    .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
355    .show = queue_nonrot_show,
356    .store = queue_nonrot_store,
357};
358
359static struct queue_sysfs_entry queue_nomerges_entry = {
360    .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
361    .show = queue_nomerges_show,
362    .store = queue_nomerges_store,
363};
364
365static struct queue_sysfs_entry queue_rq_affinity_entry = {
366    .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
367    .show = queue_rq_affinity_show,
368    .store = queue_rq_affinity_store,
369};
370
371static struct queue_sysfs_entry queue_iostats_entry = {
372    .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
373    .show = queue_iostats_show,
374    .store = queue_iostats_store,
375};
376
377static struct attribute *default_attrs[] = {
378    &queue_requests_entry.attr,
379    &queue_ra_entry.attr,
380    &queue_max_hw_sectors_entry.attr,
381    &queue_max_sectors_entry.attr,
382    &queue_max_segments_entry.attr,
383    &queue_max_segment_size_entry.attr,
384    &queue_iosched_entry.attr,
385    &queue_hw_sector_size_entry.attr,
386    &queue_logical_block_size_entry.attr,
387    &queue_physical_block_size_entry.attr,
388    &queue_io_min_entry.attr,
389    &queue_io_opt_entry.attr,
390    &queue_discard_granularity_entry.attr,
391    &queue_discard_max_entry.attr,
392    &queue_discard_zeroes_data_entry.attr,
393    &queue_nonrot_entry.attr,
394    &queue_nomerges_entry.attr,
395    &queue_rq_affinity_entry.attr,
396    &queue_iostats_entry.attr,
397    NULL,
398};
399
400#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
401
402static ssize_t
403queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
404{
405    struct queue_sysfs_entry *entry = to_queue(attr);
406    struct request_queue *q =
407        container_of(kobj, struct request_queue, kobj);
408    ssize_t res;
409
410    if (!entry->show)
411        return -EIO;
412    mutex_lock(&q->sysfs_lock);
413    if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
414        mutex_unlock(&q->sysfs_lock);
415        return -ENOENT;
416    }
417    res = entry->show(q, page);
418    mutex_unlock(&q->sysfs_lock);
419    return res;
420}
421
422static ssize_t
423queue_attr_store(struct kobject *kobj, struct attribute *attr,
424            const char *page, size_t length)
425{
426    struct queue_sysfs_entry *entry = to_queue(attr);
427    struct request_queue *q;
428    ssize_t res;
429
430    if (!entry->store)
431        return -EIO;
432
433    q = container_of(kobj, struct request_queue, kobj);
434    mutex_lock(&q->sysfs_lock);
435    if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
436        mutex_unlock(&q->sysfs_lock);
437        return -ENOENT;
438    }
439    res = entry->store(q, page, length);
440    mutex_unlock(&q->sysfs_lock);
441    return res;
442}
443
444/**
445 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
446 * @kobj: the kobj belonging of the request queue to be released
447 *
448 * Description:
449 * blk_cleanup_queue is the pair to blk_init_queue() or
450 * blk_queue_make_request(). It should be called when a request queue is
451 * being released; typically when a block device is being de-registered.
452 * Currently, its primary task it to free all the &struct request
453 * structures that were allocated to the queue and the queue itself.
454 *
455 * Caveat:
456 * Hopefully the low level driver will have finished any
457 * outstanding requests first...
458 **/
459static void blk_release_queue(struct kobject *kobj)
460{
461    struct request_queue *q =
462        container_of(kobj, struct request_queue, kobj);
463    struct request_list *rl = &q->rq;
464
465    blk_sync_queue(q);
466
467    if (rl->rq_pool)
468        mempool_destroy(rl->rq_pool);
469
470    if (q->queue_tags)
471        __blk_queue_free_tags(q);
472
473    blk_trace_shutdown(q);
474
475    bdi_destroy(&q->backing_dev_info);
476    kmem_cache_free(blk_requestq_cachep, q);
477}
478
479static const struct sysfs_ops queue_sysfs_ops = {
480    .show = queue_attr_show,
481    .store = queue_attr_store,
482};
483
484struct kobj_type blk_queue_ktype = {
485    .sysfs_ops = &queue_sysfs_ops,
486    .default_attrs = default_attrs,
487    .release = blk_release_queue,
488};
489
490int blk_register_queue(struct gendisk *disk)
491{
492    int ret;
493    struct device *dev = disk_to_dev(disk);
494
495    struct request_queue *q = disk->queue;
496
497    if (WARN_ON(!q))
498        return -ENXIO;
499
500    ret = blk_trace_init_sysfs(dev);
501    if (ret)
502        return ret;
503
504    ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
505    if (ret < 0)
506        return ret;
507
508    kobject_uevent(&q->kobj, KOBJ_ADD);
509
510    if (!q->request_fn)
511        return 0;
512
513    ret = elv_register_queue(q);
514    if (ret) {
515        kobject_uevent(&q->kobj, KOBJ_REMOVE);
516        kobject_del(&q->kobj);
517        blk_trace_remove_sysfs(disk_to_dev(disk));
518        return ret;
519    }
520
521    return 0;
522}
523
524void blk_unregister_queue(struct gendisk *disk)
525{
526    struct request_queue *q = disk->queue;
527
528    if (WARN_ON(!q))
529        return;
530
531    if (q->request_fn)
532        elv_unregister_queue(q);
533
534    kobject_uevent(&q->kobj, KOBJ_REMOVE);
535    kobject_del(&q->kobj);
536    blk_trace_remove_sysfs(disk_to_dev(disk));
537    kobject_put(&disk_to_dev(disk)->kobj);
538}
539

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