blkio: Take care of cgroup deletion and cfq group reference counting
[linux-2.6.git] / block / blk-sysfs.c
1 /*
2  * Functions related to sysfs handling
3  */
4 #include <linux/kernel.h>
5 #include <linux/module.h>
6 #include <linux/bio.h>
7 #include <linux/blkdev.h>
8 #include <linux/blktrace_api.h>
9
10 #include "blk.h"
11
12 struct queue_sysfs_entry {
13         struct attribute attr;
14         ssize_t (*show)(struct request_queue *, char *);
15         ssize_t (*store)(struct request_queue *, const char *, size_t);
16 };
17
18 static ssize_t
19 queue_var_show(unsigned long var, char *page)
20 {
21         return sprintf(page, "%lu\n", var);
22 }
23
24 static ssize_t
25 queue_var_store(unsigned long *var, const char *page, size_t count)
26 {
27         char *p = (char *) page;
28
29         *var = simple_strtoul(p, &p, 10);
30         return count;
31 }
32
33 static ssize_t queue_requests_show(struct request_queue *q, char *page)
34 {
35         return queue_var_show(q->nr_requests, (page));
36 }
37
38 static ssize_t
39 queue_requests_store(struct request_queue *q, const char *page, size_t count)
40 {
41         struct request_list *rl = &q->rq;
42         unsigned long nr;
43         int ret;
44
45         if (!q->request_fn)
46                 return -EINVAL;
47
48         ret = queue_var_store(&nr, page, count);
49         if (nr < BLKDEV_MIN_RQ)
50                 nr = BLKDEV_MIN_RQ;
51
52         spin_lock_irq(q->queue_lock);
53         q->nr_requests = nr;
54         blk_queue_congestion_threshold(q);
55
56         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
57                 blk_set_queue_congested(q, BLK_RW_SYNC);
58         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
59                 blk_clear_queue_congested(q, BLK_RW_SYNC);
60
61         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
62                 blk_set_queue_congested(q, BLK_RW_ASYNC);
63         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
64                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
65
66         if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
67                 blk_set_queue_full(q, BLK_RW_SYNC);
68         } else if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
69                 blk_clear_queue_full(q, BLK_RW_SYNC);
70                 wake_up(&rl->wait[BLK_RW_SYNC]);
71         }
72
73         if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
74                 blk_set_queue_full(q, BLK_RW_ASYNC);
75         } else if (rl->count[BLK_RW_ASYNC]+1 <= q->nr_requests) {
76                 blk_clear_queue_full(q, BLK_RW_ASYNC);
77                 wake_up(&rl->wait[BLK_RW_ASYNC]);
78         }
79         spin_unlock_irq(q->queue_lock);
80         return ret;
81 }
82
83 static ssize_t queue_ra_show(struct request_queue *q, char *page)
84 {
85         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
86                                         (PAGE_CACHE_SHIFT - 10);
87
88         return queue_var_show(ra_kb, (page));
89 }
90
91 static ssize_t
92 queue_ra_store(struct request_queue *q, const char *page, size_t count)
93 {
94         unsigned long ra_kb;
95         ssize_t ret = queue_var_store(&ra_kb, page, count);
96
97         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
98
99         return ret;
100 }
101
102 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
103 {
104         int max_sectors_kb = queue_max_sectors(q) >> 1;
105
106         return queue_var_show(max_sectors_kb, (page));
107 }
108
109 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
110 {
111         return queue_var_show(queue_logical_block_size(q), page);
112 }
113
114 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
115 {
116         return queue_var_show(queue_physical_block_size(q), page);
117 }
118
119 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
120 {
121         return queue_var_show(queue_io_min(q), page);
122 }
123
124 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
125 {
126         return queue_var_show(queue_io_opt(q), page);
127 }
128
129 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
130 {
131         return queue_var_show(q->limits.discard_granularity, page);
132 }
133
134 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
135 {
136         return queue_var_show(q->limits.max_discard_sectors << 9, page);
137 }
138
139 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
140 {
141         return queue_var_show(queue_discard_zeroes_data(q), page);
142 }
143
144 static ssize_t
145 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
146 {
147         unsigned long max_sectors_kb,
148                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
149                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
150         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
151
152         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
153                 return -EINVAL;
154
155         spin_lock_irq(q->queue_lock);
156         q->limits.max_sectors = max_sectors_kb << 1;
157         spin_unlock_irq(q->queue_lock);
158
159         return ret;
160 }
161
162 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
163 {
164         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
165
166         return queue_var_show(max_hw_sectors_kb, (page));
167 }
168
169 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
170 {
171         return queue_var_show(!blk_queue_nonrot(q), page);
172 }
173
174 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
175                                   size_t count)
176 {
177         unsigned long nm;
178         ssize_t ret = queue_var_store(&nm, page, count);
179
180         spin_lock_irq(q->queue_lock);
181         if (nm)
182                 queue_flag_clear(QUEUE_FLAG_NONROT, q);
183         else
184                 queue_flag_set(QUEUE_FLAG_NONROT, q);
185         spin_unlock_irq(q->queue_lock);
186
187         return ret;
188 }
189
190 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
191 {
192         return queue_var_show(blk_queue_nomerges(q), page);
193 }
194
195 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
196                                     size_t count)
197 {
198         unsigned long nm;
199         ssize_t ret = queue_var_store(&nm, page, count);
200
201         spin_lock_irq(q->queue_lock);
202         if (nm)
203                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
204         else
205                 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
206         spin_unlock_irq(q->queue_lock);
207
208         return ret;
209 }
210
211 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
212 {
213         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
214
215         return queue_var_show(set, page);
216 }
217
218 static ssize_t
219 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
220 {
221         ssize_t ret = -EINVAL;
222 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
223         unsigned long val;
224
225         ret = queue_var_store(&val, page, count);
226         spin_lock_irq(q->queue_lock);
227         if (val)
228                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
229         else
230                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
231         spin_unlock_irq(q->queue_lock);
232 #endif
233         return ret;
234 }
235
236 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
237 {
238         return queue_var_show(blk_queue_io_stat(q), page);
239 }
240
241 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
242                                    size_t count)
243 {
244         unsigned long stats;
245         ssize_t ret = queue_var_store(&stats, page, count);
246
247         spin_lock_irq(q->queue_lock);
248         if (stats)
249                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
250         else
251                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
252         spin_unlock_irq(q->queue_lock);
253
254         return ret;
255 }
256
257 static struct queue_sysfs_entry queue_requests_entry = {
258         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
259         .show = queue_requests_show,
260         .store = queue_requests_store,
261 };
262
263 static struct queue_sysfs_entry queue_ra_entry = {
264         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
265         .show = queue_ra_show,
266         .store = queue_ra_store,
267 };
268
269 static struct queue_sysfs_entry queue_max_sectors_entry = {
270         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
271         .show = queue_max_sectors_show,
272         .store = queue_max_sectors_store,
273 };
274
275 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
276         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
277         .show = queue_max_hw_sectors_show,
278 };
279
280 static struct queue_sysfs_entry queue_iosched_entry = {
281         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
282         .show = elv_iosched_show,
283         .store = elv_iosched_store,
284 };
285
286 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
287         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
288         .show = queue_logical_block_size_show,
289 };
290
291 static struct queue_sysfs_entry queue_logical_block_size_entry = {
292         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
293         .show = queue_logical_block_size_show,
294 };
295
296 static struct queue_sysfs_entry queue_physical_block_size_entry = {
297         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
298         .show = queue_physical_block_size_show,
299 };
300
301 static struct queue_sysfs_entry queue_io_min_entry = {
302         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
303         .show = queue_io_min_show,
304 };
305
306 static struct queue_sysfs_entry queue_io_opt_entry = {
307         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
308         .show = queue_io_opt_show,
309 };
310
311 static struct queue_sysfs_entry queue_discard_granularity_entry = {
312         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
313         .show = queue_discard_granularity_show,
314 };
315
316 static struct queue_sysfs_entry queue_discard_max_entry = {
317         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
318         .show = queue_discard_max_show,
319 };
320
321 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
322         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
323         .show = queue_discard_zeroes_data_show,
324 };
325
326 static struct queue_sysfs_entry queue_nonrot_entry = {
327         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
328         .show = queue_nonrot_show,
329         .store = queue_nonrot_store,
330 };
331
332 static struct queue_sysfs_entry queue_nomerges_entry = {
333         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
334         .show = queue_nomerges_show,
335         .store = queue_nomerges_store,
336 };
337
338 static struct queue_sysfs_entry queue_rq_affinity_entry = {
339         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
340         .show = queue_rq_affinity_show,
341         .store = queue_rq_affinity_store,
342 };
343
344 static struct queue_sysfs_entry queue_iostats_entry = {
345         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
346         .show = queue_iostats_show,
347         .store = queue_iostats_store,
348 };
349
350 static struct attribute *default_attrs[] = {
351         &queue_requests_entry.attr,
352         &queue_ra_entry.attr,
353         &queue_max_hw_sectors_entry.attr,
354         &queue_max_sectors_entry.attr,
355         &queue_iosched_entry.attr,
356         &queue_hw_sector_size_entry.attr,
357         &queue_logical_block_size_entry.attr,
358         &queue_physical_block_size_entry.attr,
359         &queue_io_min_entry.attr,
360         &queue_io_opt_entry.attr,
361         &queue_discard_granularity_entry.attr,
362         &queue_discard_max_entry.attr,
363         &queue_discard_zeroes_data_entry.attr,
364         &queue_nonrot_entry.attr,
365         &queue_nomerges_entry.attr,
366         &queue_rq_affinity_entry.attr,
367         &queue_iostats_entry.attr,
368         NULL,
369 };
370
371 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
372
373 static ssize_t
374 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
375 {
376         struct queue_sysfs_entry *entry = to_queue(attr);
377         struct request_queue *q =
378                 container_of(kobj, struct request_queue, kobj);
379         ssize_t res;
380
381         if (!entry->show)
382                 return -EIO;
383         mutex_lock(&q->sysfs_lock);
384         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
385                 mutex_unlock(&q->sysfs_lock);
386                 return -ENOENT;
387         }
388         res = entry->show(q, page);
389         mutex_unlock(&q->sysfs_lock);
390         return res;
391 }
392
393 static ssize_t
394 queue_attr_store(struct kobject *kobj, struct attribute *attr,
395                     const char *page, size_t length)
396 {
397         struct queue_sysfs_entry *entry = to_queue(attr);
398         struct request_queue *q;
399         ssize_t res;
400
401         if (!entry->store)
402                 return -EIO;
403
404         q = container_of(kobj, struct request_queue, kobj);
405         mutex_lock(&q->sysfs_lock);
406         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
407                 mutex_unlock(&q->sysfs_lock);
408                 return -ENOENT;
409         }
410         res = entry->store(q, page, length);
411         mutex_unlock(&q->sysfs_lock);
412         return res;
413 }
414
415 /**
416  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
417  * @kobj:    the kobj belonging of the request queue to be released
418  *
419  * Description:
420  *     blk_cleanup_queue is the pair to blk_init_queue() or
421  *     blk_queue_make_request().  It should be called when a request queue is
422  *     being released; typically when a block device is being de-registered.
423  *     Currently, its primary task it to free all the &struct request
424  *     structures that were allocated to the queue and the queue itself.
425  *
426  * Caveat:
427  *     Hopefully the low level driver will have finished any
428  *     outstanding requests first...
429  **/
430 static void blk_release_queue(struct kobject *kobj)
431 {
432         struct request_queue *q =
433                 container_of(kobj, struct request_queue, kobj);
434         struct request_list *rl = &q->rq;
435
436         blk_sync_queue(q);
437
438         if (rl->rq_pool)
439                 mempool_destroy(rl->rq_pool);
440
441         if (q->queue_tags)
442                 __blk_queue_free_tags(q);
443
444         blk_trace_shutdown(q);
445
446         bdi_destroy(&q->backing_dev_info);
447         kmem_cache_free(blk_requestq_cachep, q);
448 }
449
450 static struct sysfs_ops queue_sysfs_ops = {
451         .show   = queue_attr_show,
452         .store  = queue_attr_store,
453 };
454
455 struct kobj_type blk_queue_ktype = {
456         .sysfs_ops      = &queue_sysfs_ops,
457         .default_attrs  = default_attrs,
458         .release        = blk_release_queue,
459 };
460
461 int blk_register_queue(struct gendisk *disk)
462 {
463         int ret;
464         struct device *dev = disk_to_dev(disk);
465
466         struct request_queue *q = disk->queue;
467
468         if (WARN_ON(!q))
469                 return -ENXIO;
470
471         ret = blk_trace_init_sysfs(dev);
472         if (ret)
473                 return ret;
474
475         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
476         if (ret < 0)
477                 return ret;
478
479         kobject_uevent(&q->kobj, KOBJ_ADD);
480
481         if (!q->request_fn)
482                 return 0;
483
484         ret = elv_register_queue(q);
485         if (ret) {
486                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
487                 kobject_del(&q->kobj);
488                 blk_trace_remove_sysfs(disk_to_dev(disk));
489                 return ret;
490         }
491
492         return 0;
493 }
494
495 void blk_unregister_queue(struct gendisk *disk)
496 {
497         struct request_queue *q = disk->queue;
498
499         if (WARN_ON(!q))
500                 return;
501
502         if (q->request_fn)
503                 elv_unregister_queue(q);
504
505         kobject_uevent(&q->kobj, KOBJ_REMOVE);
506         kobject_del(&q->kobj);
507         blk_trace_remove_sysfs(disk_to_dev(disk));
508         kobject_put(&disk_to_dev(disk)->kobj);
509 }