Merge branch 'for-2.6.31' of git://git.kernel.dk/linux-2.6-block
[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 int var, char *page)
20 {
21         return sprintf(page, "%d\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 = queue_var_store(&nr, page, count);
44         if (nr < BLKDEV_MIN_RQ)
45                 nr = BLKDEV_MIN_RQ;
46
47         spin_lock_irq(q->queue_lock);
48         q->nr_requests = nr;
49         blk_queue_congestion_threshold(q);
50
51         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
52                 blk_set_queue_congested(q, BLK_RW_SYNC);
53         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
54                 blk_clear_queue_congested(q, BLK_RW_SYNC);
55
56         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
57                 blk_set_queue_congested(q, BLK_RW_ASYNC);
58         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
59                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
60
61         if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
62                 blk_set_queue_full(q, BLK_RW_SYNC);
63         } else if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
64                 blk_clear_queue_full(q, BLK_RW_SYNC);
65                 wake_up(&rl->wait[BLK_RW_SYNC]);
66         }
67
68         if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
69                 blk_set_queue_full(q, BLK_RW_ASYNC);
70         } else if (rl->count[BLK_RW_ASYNC]+1 <= q->nr_requests) {
71                 blk_clear_queue_full(q, BLK_RW_ASYNC);
72                 wake_up(&rl->wait[BLK_RW_ASYNC]);
73         }
74         spin_unlock_irq(q->queue_lock);
75         return ret;
76 }
77
78 static ssize_t queue_ra_show(struct request_queue *q, char *page)
79 {
80         int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
81
82         return queue_var_show(ra_kb, (page));
83 }
84
85 static ssize_t
86 queue_ra_store(struct request_queue *q, const char *page, size_t count)
87 {
88         unsigned long ra_kb;
89         ssize_t ret = queue_var_store(&ra_kb, page, count);
90
91         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
92
93         return ret;
94 }
95
96 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
97 {
98         int max_sectors_kb = queue_max_sectors(q) >> 1;
99
100         return queue_var_show(max_sectors_kb, (page));
101 }
102
103 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
104 {
105         return queue_var_show(queue_logical_block_size(q), page);
106 }
107
108 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
109 {
110         return queue_var_show(queue_physical_block_size(q), page);
111 }
112
113 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
114 {
115         return queue_var_show(queue_io_min(q), page);
116 }
117
118 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
119 {
120         return queue_var_show(queue_io_opt(q), page);
121 }
122
123 static ssize_t
124 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
125 {
126         unsigned long max_sectors_kb,
127                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
128                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
129         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
130
131         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
132                 return -EINVAL;
133
134         spin_lock_irq(q->queue_lock);
135         blk_queue_max_sectors(q, max_sectors_kb << 1);
136         spin_unlock_irq(q->queue_lock);
137
138         return ret;
139 }
140
141 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
142 {
143         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
144
145         return queue_var_show(max_hw_sectors_kb, (page));
146 }
147
148 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
149 {
150         return queue_var_show(!blk_queue_nonrot(q), page);
151 }
152
153 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
154                                   size_t count)
155 {
156         unsigned long nm;
157         ssize_t ret = queue_var_store(&nm, page, count);
158
159         spin_lock_irq(q->queue_lock);
160         if (nm)
161                 queue_flag_clear(QUEUE_FLAG_NONROT, q);
162         else
163                 queue_flag_set(QUEUE_FLAG_NONROT, q);
164         spin_unlock_irq(q->queue_lock);
165
166         return ret;
167 }
168
169 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
170 {
171         return queue_var_show(blk_queue_nomerges(q), page);
172 }
173
174 static ssize_t queue_nomerges_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_set(QUEUE_FLAG_NOMERGES, q);
183         else
184                 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
185         spin_unlock_irq(q->queue_lock);
186
187         return ret;
188 }
189
190 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
191 {
192         unsigned int set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
193
194         return queue_var_show(set != 0, page);
195 }
196
197 static ssize_t
198 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
199 {
200         ssize_t ret = -EINVAL;
201 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
202         unsigned long val;
203
204         ret = queue_var_store(&val, page, count);
205         spin_lock_irq(q->queue_lock);
206         if (val)
207                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
208         else
209                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
210         spin_unlock_irq(q->queue_lock);
211 #endif
212         return ret;
213 }
214
215 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
216 {
217         return queue_var_show(blk_queue_io_stat(q), page);
218 }
219
220 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
221                                    size_t count)
222 {
223         unsigned long stats;
224         ssize_t ret = queue_var_store(&stats, page, count);
225
226         spin_lock_irq(q->queue_lock);
227         if (stats)
228                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
229         else
230                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
231         spin_unlock_irq(q->queue_lock);
232
233         return ret;
234 }
235
236 static struct queue_sysfs_entry queue_requests_entry = {
237         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
238         .show = queue_requests_show,
239         .store = queue_requests_store,
240 };
241
242 static struct queue_sysfs_entry queue_ra_entry = {
243         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
244         .show = queue_ra_show,
245         .store = queue_ra_store,
246 };
247
248 static struct queue_sysfs_entry queue_max_sectors_entry = {
249         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
250         .show = queue_max_sectors_show,
251         .store = queue_max_sectors_store,
252 };
253
254 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
255         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
256         .show = queue_max_hw_sectors_show,
257 };
258
259 static struct queue_sysfs_entry queue_iosched_entry = {
260         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
261         .show = elv_iosched_show,
262         .store = elv_iosched_store,
263 };
264
265 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
266         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
267         .show = queue_logical_block_size_show,
268 };
269
270 static struct queue_sysfs_entry queue_logical_block_size_entry = {
271         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
272         .show = queue_logical_block_size_show,
273 };
274
275 static struct queue_sysfs_entry queue_physical_block_size_entry = {
276         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
277         .show = queue_physical_block_size_show,
278 };
279
280 static struct queue_sysfs_entry queue_io_min_entry = {
281         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
282         .show = queue_io_min_show,
283 };
284
285 static struct queue_sysfs_entry queue_io_opt_entry = {
286         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
287         .show = queue_io_opt_show,
288 };
289
290 static struct queue_sysfs_entry queue_nonrot_entry = {
291         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
292         .show = queue_nonrot_show,
293         .store = queue_nonrot_store,
294 };
295
296 static struct queue_sysfs_entry queue_nomerges_entry = {
297         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
298         .show = queue_nomerges_show,
299         .store = queue_nomerges_store,
300 };
301
302 static struct queue_sysfs_entry queue_rq_affinity_entry = {
303         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
304         .show = queue_rq_affinity_show,
305         .store = queue_rq_affinity_store,
306 };
307
308 static struct queue_sysfs_entry queue_iostats_entry = {
309         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
310         .show = queue_iostats_show,
311         .store = queue_iostats_store,
312 };
313
314 static struct attribute *default_attrs[] = {
315         &queue_requests_entry.attr,
316         &queue_ra_entry.attr,
317         &queue_max_hw_sectors_entry.attr,
318         &queue_max_sectors_entry.attr,
319         &queue_iosched_entry.attr,
320         &queue_hw_sector_size_entry.attr,
321         &queue_logical_block_size_entry.attr,
322         &queue_physical_block_size_entry.attr,
323         &queue_io_min_entry.attr,
324         &queue_io_opt_entry.attr,
325         &queue_nonrot_entry.attr,
326         &queue_nomerges_entry.attr,
327         &queue_rq_affinity_entry.attr,
328         &queue_iostats_entry.attr,
329         NULL,
330 };
331
332 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
333
334 static ssize_t
335 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
336 {
337         struct queue_sysfs_entry *entry = to_queue(attr);
338         struct request_queue *q =
339                 container_of(kobj, struct request_queue, kobj);
340         ssize_t res;
341
342         if (!entry->show)
343                 return -EIO;
344         mutex_lock(&q->sysfs_lock);
345         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
346                 mutex_unlock(&q->sysfs_lock);
347                 return -ENOENT;
348         }
349         res = entry->show(q, page);
350         mutex_unlock(&q->sysfs_lock);
351         return res;
352 }
353
354 static ssize_t
355 queue_attr_store(struct kobject *kobj, struct attribute *attr,
356                     const char *page, size_t length)
357 {
358         struct queue_sysfs_entry *entry = to_queue(attr);
359         struct request_queue *q;
360         ssize_t res;
361
362         if (!entry->store)
363                 return -EIO;
364
365         q = container_of(kobj, struct request_queue, kobj);
366         mutex_lock(&q->sysfs_lock);
367         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
368                 mutex_unlock(&q->sysfs_lock);
369                 return -ENOENT;
370         }
371         res = entry->store(q, page, length);
372         mutex_unlock(&q->sysfs_lock);
373         return res;
374 }
375
376 /**
377  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
378  * @kobj:    the kobj belonging of the request queue to be released
379  *
380  * Description:
381  *     blk_cleanup_queue is the pair to blk_init_queue() or
382  *     blk_queue_make_request().  It should be called when a request queue is
383  *     being released; typically when a block device is being de-registered.
384  *     Currently, its primary task it to free all the &struct request
385  *     structures that were allocated to the queue and the queue itself.
386  *
387  * Caveat:
388  *     Hopefully the low level driver will have finished any
389  *     outstanding requests first...
390  **/
391 static void blk_release_queue(struct kobject *kobj)
392 {
393         struct request_queue *q =
394                 container_of(kobj, struct request_queue, kobj);
395         struct request_list *rl = &q->rq;
396
397         blk_sync_queue(q);
398
399         if (rl->rq_pool)
400                 mempool_destroy(rl->rq_pool);
401
402         if (q->queue_tags)
403                 __blk_queue_free_tags(q);
404
405         blk_trace_shutdown(q);
406
407         bdi_destroy(&q->backing_dev_info);
408         kmem_cache_free(blk_requestq_cachep, q);
409 }
410
411 static struct sysfs_ops queue_sysfs_ops = {
412         .show   = queue_attr_show,
413         .store  = queue_attr_store,
414 };
415
416 struct kobj_type blk_queue_ktype = {
417         .sysfs_ops      = &queue_sysfs_ops,
418         .default_attrs  = default_attrs,
419         .release        = blk_release_queue,
420 };
421
422 int blk_register_queue(struct gendisk *disk)
423 {
424         int ret;
425         struct device *dev = disk_to_dev(disk);
426
427         struct request_queue *q = disk->queue;
428
429         if (WARN_ON(!q))
430                 return -ENXIO;
431
432         ret = blk_trace_init_sysfs(dev);
433         if (ret)
434                 return ret;
435
436         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
437         if (ret < 0)
438                 return ret;
439
440         kobject_uevent(&q->kobj, KOBJ_ADD);
441
442         if (!q->request_fn)
443                 return 0;
444
445         ret = elv_register_queue(q);
446         if (ret) {
447                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
448                 kobject_del(&q->kobj);
449                 return ret;
450         }
451
452         return 0;
453 }
454
455 void blk_unregister_queue(struct gendisk *disk)
456 {
457         struct request_queue *q = disk->queue;
458
459         if (WARN_ON(!q))
460                 return;
461
462         if (q->request_fn) {
463                 elv_unregister_queue(q);
464
465                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
466                 kobject_del(&q->kobj);
467                 kobject_put(&disk_to_dev(disk)->kobj);
468         }
469 }