CFQ: add think time check for service tree
[linux-2.6.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
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
248         return queue_var_show(set, page);
249 }
250
251 static ssize_t
252 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
253 {
254         ssize_t ret = -EINVAL;
255 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
256         unsigned long val;
257
258         ret = queue_var_store(&val, page, count);
259         spin_lock_irq(q->queue_lock);
260         if (val)
261                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
262         else
263                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
264         spin_unlock_irq(q->queue_lock);
265 #endif
266         return ret;
267 }
268
269 static struct queue_sysfs_entry queue_requests_entry = {
270         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
271         .show = queue_requests_show,
272         .store = queue_requests_store,
273 };
274
275 static struct queue_sysfs_entry queue_ra_entry = {
276         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
277         .show = queue_ra_show,
278         .store = queue_ra_store,
279 };
280
281 static struct queue_sysfs_entry queue_max_sectors_entry = {
282         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
283         .show = queue_max_sectors_show,
284         .store = queue_max_sectors_store,
285 };
286
287 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
288         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
289         .show = queue_max_hw_sectors_show,
290 };
291
292 static struct queue_sysfs_entry queue_max_segments_entry = {
293         .attr = {.name = "max_segments", .mode = S_IRUGO },
294         .show = queue_max_segments_show,
295 };
296
297 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
298         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
299         .show = queue_max_integrity_segments_show,
300 };
301
302 static 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
307 static 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
313 static 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
318 static 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
323 static 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
328 static 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
333 static 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
338 static struct queue_sysfs_entry queue_discard_granularity_entry = {
339         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
340         .show = queue_discard_granularity_show,
341 };
342
343 static 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
348 static 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
353 static struct queue_sysfs_entry queue_nonrot_entry = {
354         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
355         .show = queue_show_nonrot,
356         .store = queue_store_nonrot,
357 };
358
359 static 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
365 static 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
371 static struct queue_sysfs_entry queue_iostats_entry = {
372         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
373         .show = queue_show_iostats,
374         .store = queue_store_iostats,
375 };
376
377 static struct queue_sysfs_entry queue_random_entry = {
378         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
379         .show = queue_show_random,
380         .store = queue_store_random,
381 };
382
383 static struct attribute *default_attrs[] = {
384         &queue_requests_entry.attr,
385         &queue_ra_entry.attr,
386         &queue_max_hw_sectors_entry.attr,
387         &queue_max_sectors_entry.attr,
388         &queue_max_segments_entry.attr,
389         &queue_max_integrity_segments_entry.attr,
390         &queue_max_segment_size_entry.attr,
391         &queue_iosched_entry.attr,
392         &queue_hw_sector_size_entry.attr,
393         &queue_logical_block_size_entry.attr,
394         &queue_physical_block_size_entry.attr,
395         &queue_io_min_entry.attr,
396         &queue_io_opt_entry.attr,
397         &queue_discard_granularity_entry.attr,
398         &queue_discard_max_entry.attr,
399         &queue_discard_zeroes_data_entry.attr,
400         &queue_nonrot_entry.attr,
401         &queue_nomerges_entry.attr,
402         &queue_rq_affinity_entry.attr,
403         &queue_iostats_entry.attr,
404         &queue_random_entry.attr,
405         NULL,
406 };
407
408 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
409
410 static ssize_t
411 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
412 {
413         struct queue_sysfs_entry *entry = to_queue(attr);
414         struct request_queue *q =
415                 container_of(kobj, struct request_queue, kobj);
416         ssize_t res;
417
418         if (!entry->show)
419                 return -EIO;
420         mutex_lock(&q->sysfs_lock);
421         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
422                 mutex_unlock(&q->sysfs_lock);
423                 return -ENOENT;
424         }
425         res = entry->show(q, page);
426         mutex_unlock(&q->sysfs_lock);
427         return res;
428 }
429
430 static ssize_t
431 queue_attr_store(struct kobject *kobj, struct attribute *attr,
432                     const char *page, size_t length)
433 {
434         struct queue_sysfs_entry *entry = to_queue(attr);
435         struct request_queue *q;
436         ssize_t res;
437
438         if (!entry->store)
439                 return -EIO;
440
441         q = container_of(kobj, struct request_queue, kobj);
442         mutex_lock(&q->sysfs_lock);
443         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
444                 mutex_unlock(&q->sysfs_lock);
445                 return -ENOENT;
446         }
447         res = entry->store(q, page, length);
448         mutex_unlock(&q->sysfs_lock);
449         return res;
450 }
451
452 /**
453  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
454  * @kobj:    the kobj belonging of the request queue to be released
455  *
456  * Description:
457  *     blk_cleanup_queue is the pair to blk_init_queue() or
458  *     blk_queue_make_request().  It should be called when a request queue is
459  *     being released; typically when a block device is being de-registered.
460  *     Currently, its primary task it to free all the &struct request
461  *     structures that were allocated to the queue and the queue itself.
462  *
463  * Caveat:
464  *     Hopefully the low level driver will have finished any
465  *     outstanding requests first...
466  **/
467 static void blk_release_queue(struct kobject *kobj)
468 {
469         struct request_queue *q =
470                 container_of(kobj, struct request_queue, kobj);
471         struct request_list *rl = &q->rq;
472
473         blk_sync_queue(q);
474
475         if (rl->rq_pool)
476                 mempool_destroy(rl->rq_pool);
477
478         if (q->queue_tags)
479                 __blk_queue_free_tags(q);
480
481         blk_trace_shutdown(q);
482
483         bdi_destroy(&q->backing_dev_info);
484         kmem_cache_free(blk_requestq_cachep, q);
485 }
486
487 static const struct sysfs_ops queue_sysfs_ops = {
488         .show   = queue_attr_show,
489         .store  = queue_attr_store,
490 };
491
492 struct kobj_type blk_queue_ktype = {
493         .sysfs_ops      = &queue_sysfs_ops,
494         .default_attrs  = default_attrs,
495         .release        = blk_release_queue,
496 };
497
498 int blk_register_queue(struct gendisk *disk)
499 {
500         int ret;
501         struct device *dev = disk_to_dev(disk);
502         struct request_queue *q = disk->queue;
503
504         if (WARN_ON(!q))
505                 return -ENXIO;
506
507         ret = blk_trace_init_sysfs(dev);
508         if (ret)
509                 return ret;
510
511         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
512         if (ret < 0) {
513                 blk_trace_remove_sysfs(dev);
514                 return ret;
515         }
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(dev);
527                 kobject_put(&dev->kobj);
528                 return ret;
529         }
530
531         return 0;
532 }
533
534 void 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 }