block: dump request state on seeing a corrupted request completion
[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 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
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 queue_var_show(q->limits.max_discard_sectors << 9, page);
156 }
157
158 static 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
163 static ssize_t
164 queue_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
181 static 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)                            \
189 static ssize_t                                                          \
190 queue_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 }                                                                       \
196 static ssize_t                                                          \
197 queue_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
214 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
215 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
216 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
217 #undef QUEUE_SYSFS_BIT_FNS
218
219 static 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
225 static 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
243 static 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
250 static ssize_t
251 queue_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
268 static 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
274 static 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
280 static 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
286 static 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
291 static struct queue_sysfs_entry queue_max_segments_entry = {
292         .attr = {.name = "max_segments", .mode = S_IRUGO },
293         .show = queue_max_segments_show,
294 };
295
296 static 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
301 static 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
306 static 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
312 static 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
317 static 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
322 static 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
327 static 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
332 static 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
337 static struct queue_sysfs_entry queue_discard_granularity_entry = {
338         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
339         .show = queue_discard_granularity_show,
340 };
341
342 static 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
347 static 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
352 static 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
358 static 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
364 static 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
370 static 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
376 static 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
382 static 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
409 static ssize_t
410 queue_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
429 static ssize_t
430 queue_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  **/
466 static 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         if (rl->rq_pool)
475                 mempool_destroy(rl->rq_pool);
476
477         if (q->queue_tags)
478                 __blk_queue_free_tags(q);
479
480         blk_trace_shutdown(q);
481
482         bdi_destroy(&q->backing_dev_info);
483         kmem_cache_free(blk_requestq_cachep, q);
484 }
485
486 static const struct sysfs_ops queue_sysfs_ops = {
487         .show   = queue_attr_show,
488         .store  = queue_attr_store,
489 };
490
491 struct kobj_type blk_queue_ktype = {
492         .sysfs_ops      = &queue_sysfs_ops,
493         .default_attrs  = default_attrs,
494         .release        = blk_release_queue,
495 };
496
497 int blk_register_queue(struct gendisk *disk)
498 {
499         int ret;
500         struct device *dev = disk_to_dev(disk);
501
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                 return ret;
514
515         kobject_uevent(&q->kobj, KOBJ_ADD);
516
517         if (!q->request_fn)
518                 return 0;
519
520         ret = elv_register_queue(q);
521         if (ret) {
522                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
523                 kobject_del(&q->kobj);
524                 blk_trace_remove_sysfs(disk_to_dev(disk));
525                 kobject_put(&dev->kobj);
526                 return ret;
527         }
528
529         return 0;
530 }
531
532 void blk_unregister_queue(struct gendisk *disk)
533 {
534         struct request_queue *q = disk->queue;
535
536         if (WARN_ON(!q))
537                 return;
538
539         if (q->request_fn)
540                 elv_unregister_queue(q);
541
542         kobject_uevent(&q->kobj, KOBJ_REMOVE);
543         kobject_del(&q->kobj);
544         blk_trace_remove_sysfs(disk_to_dev(disk));
545         kobject_put(&disk_to_dev(disk)->kobj);
546 }