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
queue_var_show(unsigned int var,char * page)19 queue_var_show(unsigned int var, char *page)
20 {
21 return sprintf(page, "%d\n", var);
22 }
23
24 static ssize_t
queue_var_store(unsigned long * var,const char * page,size_t count)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
queue_requests_show(struct request_queue * q,char * page)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
queue_requests_store(struct request_queue * q,const char * page,size_t count)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[READ] >= queue_congestion_on_threshold(q))
52 blk_set_queue_congested(q, READ);
53 else if (rl->count[READ] < queue_congestion_off_threshold(q))
54 blk_clear_queue_congested(q, READ);
55
56 if (rl->count[WRITE] >= queue_congestion_on_threshold(q))
57 blk_set_queue_congested(q, WRITE);
58 else if (rl->count[WRITE] < queue_congestion_off_threshold(q))
59 blk_clear_queue_congested(q, WRITE);
60
61 if (rl->count[READ] >= q->nr_requests) {
62 blk_set_queue_full(q, READ);
63 } else if (rl->count[READ]+1 <= q->nr_requests) {
64 blk_clear_queue_full(q, READ);
65 wake_up(&rl->wait[READ]);
66 }
67
68 if (rl->count[WRITE] >= q->nr_requests) {
69 blk_set_queue_full(q, WRITE);
70 } else if (rl->count[WRITE]+1 <= q->nr_requests) {
71 blk_clear_queue_full(q, WRITE);
72 wake_up(&rl->wait[WRITE]);
73 }
74 spin_unlock_irq(q->queue_lock);
75 return ret;
76 }
77
queue_ra_show(struct request_queue * q,char * page)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
queue_ra_store(struct request_queue * q,const char * page,size_t count)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
queue_max_sectors_show(struct request_queue * q,char * page)96 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
97 {
98 int max_sectors_kb = q->max_sectors >> 1;
99
100 return queue_var_show(max_sectors_kb, (page));
101 }
102
queue_hw_sector_size_show(struct request_queue * q,char * page)103 static ssize_t queue_hw_sector_size_show(struct request_queue *q, char *page)
104 {
105 return queue_var_show(q->hardsect_size, page);
106 }
107
108 static ssize_t
queue_max_sectors_store(struct request_queue * q,const char * page,size_t count)109 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
110 {
111 unsigned long max_sectors_kb,
112 max_hw_sectors_kb = q->max_hw_sectors >> 1,
113 page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
114 ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
115
116 if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
117 return -EINVAL;
118
119 spin_lock_irq(q->queue_lock);
120 q->max_sectors = max_sectors_kb << 1;
121 spin_unlock_irq(q->queue_lock);
122
123 return ret;
124 }
125
queue_max_hw_sectors_show(struct request_queue * q,char * page)126 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
127 {
128 int max_hw_sectors_kb = q->max_hw_sectors >> 1;
129
130 return queue_var_show(max_hw_sectors_kb, (page));
131 }
132
queue_nonrot_show(struct request_queue * q,char * page)133 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
134 {
135 return queue_var_show(!blk_queue_nonrot(q), page);
136 }
137
queue_nonrot_store(struct request_queue * q,const char * page,size_t count)138 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
139 size_t count)
140 {
141 unsigned long nm;
142 ssize_t ret = queue_var_store(&nm, page, count);
143
144 spin_lock_irq(q->queue_lock);
145 if (nm)
146 queue_flag_clear(QUEUE_FLAG_NONROT, q);
147 else
148 queue_flag_set(QUEUE_FLAG_NONROT, q);
149 spin_unlock_irq(q->queue_lock);
150
151 return ret;
152 }
153
queue_nomerges_show(struct request_queue * q,char * page)154 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
155 {
156 return queue_var_show(blk_queue_nomerges(q), page);
157 }
158
queue_nomerges_store(struct request_queue * q,const char * page,size_t count)159 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
160 size_t count)
161 {
162 unsigned long nm;
163 ssize_t ret = queue_var_store(&nm, page, count);
164
165 spin_lock_irq(q->queue_lock);
166 if (nm)
167 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
168 else
169 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
170 spin_unlock_irq(q->queue_lock);
171
172 return ret;
173 }
174
queue_rq_affinity_show(struct request_queue * q,char * page)175 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
176 {
177 unsigned int set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
178
179 return queue_var_show(set != 0, page);
180 }
181
182 static ssize_t
queue_rq_affinity_store(struct request_queue * q,const char * page,size_t count)183 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
184 {
185 ssize_t ret = -EINVAL;
186 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
187 unsigned long val;
188
189 ret = queue_var_store(&val, page, count);
190 spin_lock_irq(q->queue_lock);
191 if (val)
192 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
193 else
194 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
195 spin_unlock_irq(q->queue_lock);
196 #endif
197 return ret;
198 }
199
queue_iostats_show(struct request_queue * q,char * page)200 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
201 {
202 return queue_var_show(blk_queue_io_stat(q), page);
203 }
204
queue_iostats_store(struct request_queue * q,const char * page,size_t count)205 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
206 size_t count)
207 {
208 unsigned long stats;
209 ssize_t ret = queue_var_store(&stats, page, count);
210
211 spin_lock_irq(q->queue_lock);
212 if (stats)
213 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
214 else
215 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
216 spin_unlock_irq(q->queue_lock);
217
218 return ret;
219 }
220
221 static struct queue_sysfs_entry queue_requests_entry = {
222 .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
223 .show = queue_requests_show,
224 .store = queue_requests_store,
225 };
226
227 static struct queue_sysfs_entry queue_ra_entry = {
228 .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
229 .show = queue_ra_show,
230 .store = queue_ra_store,
231 };
232
233 static struct queue_sysfs_entry queue_max_sectors_entry = {
234 .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
235 .show = queue_max_sectors_show,
236 .store = queue_max_sectors_store,
237 };
238
239 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
240 .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
241 .show = queue_max_hw_sectors_show,
242 };
243
244 static struct queue_sysfs_entry queue_iosched_entry = {
245 .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
246 .show = elv_iosched_show,
247 .store = elv_iosched_store,
248 };
249
250 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
251 .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
252 .show = queue_hw_sector_size_show,
253 };
254
255 static struct queue_sysfs_entry queue_nonrot_entry = {
256 .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
257 .show = queue_nonrot_show,
258 .store = queue_nonrot_store,
259 };
260
261 static struct queue_sysfs_entry queue_nomerges_entry = {
262 .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
263 .show = queue_nomerges_show,
264 .store = queue_nomerges_store,
265 };
266
267 static struct queue_sysfs_entry queue_rq_affinity_entry = {
268 .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
269 .show = queue_rq_affinity_show,
270 .store = queue_rq_affinity_store,
271 };
272
273 static struct queue_sysfs_entry queue_iostats_entry = {
274 .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
275 .show = queue_iostats_show,
276 .store = queue_iostats_store,
277 };
278
279 static struct attribute *default_attrs[] = {
280 &queue_requests_entry.attr,
281 &queue_ra_entry.attr,
282 &queue_max_hw_sectors_entry.attr,
283 &queue_max_sectors_entry.attr,
284 &queue_iosched_entry.attr,
285 &queue_hw_sector_size_entry.attr,
286 &queue_nonrot_entry.attr,
287 &queue_nomerges_entry.attr,
288 &queue_rq_affinity_entry.attr,
289 &queue_iostats_entry.attr,
290 NULL,
291 };
292
293 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
294
295 static ssize_t
queue_attr_show(struct kobject * kobj,struct attribute * attr,char * page)296 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
297 {
298 struct queue_sysfs_entry *entry = to_queue(attr);
299 struct request_queue *q =
300 container_of(kobj, struct request_queue, kobj);
301 ssize_t res;
302
303 if (!entry->show)
304 return -EIO;
305 mutex_lock(&q->sysfs_lock);
306 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
307 mutex_unlock(&q->sysfs_lock);
308 return -ENOENT;
309 }
310 res = entry->show(q, page);
311 mutex_unlock(&q->sysfs_lock);
312 return res;
313 }
314
315 static ssize_t
queue_attr_store(struct kobject * kobj,struct attribute * attr,const char * page,size_t length)316 queue_attr_store(struct kobject *kobj, struct attribute *attr,
317 const char *page, size_t length)
318 {
319 struct queue_sysfs_entry *entry = to_queue(attr);
320 struct request_queue *q;
321 ssize_t res;
322
323 if (!entry->store)
324 return -EIO;
325
326 q = container_of(kobj, struct request_queue, kobj);
327 mutex_lock(&q->sysfs_lock);
328 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
329 mutex_unlock(&q->sysfs_lock);
330 return -ENOENT;
331 }
332 res = entry->store(q, page, length);
333 mutex_unlock(&q->sysfs_lock);
334 return res;
335 }
336
337 /**
338 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
339 * @kobj: the kobj belonging of the request queue to be released
340 *
341 * Description:
342 * blk_cleanup_queue is the pair to blk_init_queue() or
343 * blk_queue_make_request(). It should be called when a request queue is
344 * being released; typically when a block device is being de-registered.
345 * Currently, its primary task it to free all the &struct request
346 * structures that were allocated to the queue and the queue itself.
347 *
348 * Caveat:
349 * Hopefully the low level driver will have finished any
350 * outstanding requests first...
351 **/
blk_release_queue(struct kobject * kobj)352 static void blk_release_queue(struct kobject *kobj)
353 {
354 struct request_queue *q =
355 container_of(kobj, struct request_queue, kobj);
356 struct request_list *rl = &q->rq;
357
358 blk_sync_queue(q);
359
360 if (rl->rq_pool)
361 mempool_destroy(rl->rq_pool);
362
363 if (q->queue_tags)
364 __blk_queue_free_tags(q);
365
366 blk_trace_shutdown(q);
367
368 bdi_destroy(&q->backing_dev_info);
369 kmem_cache_free(blk_requestq_cachep, q);
370 }
371
372 static struct sysfs_ops queue_sysfs_ops = {
373 .show = queue_attr_show,
374 .store = queue_attr_store,
375 };
376
377 struct kobj_type blk_queue_ktype = {
378 .sysfs_ops = &queue_sysfs_ops,
379 .default_attrs = default_attrs,
380 .release = blk_release_queue,
381 };
382
blk_register_queue(struct gendisk * disk)383 int blk_register_queue(struct gendisk *disk)
384 {
385 int ret;
386
387 struct request_queue *q = disk->queue;
388
389 if (WARN_ON(!q))
390 return -ENXIO;
391
392 if (!q->request_fn)
393 return 0;
394
395 ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj),
396 "%s", "queue");
397 if (ret < 0)
398 return ret;
399
400 kobject_uevent(&q->kobj, KOBJ_ADD);
401
402 ret = elv_register_queue(q);
403 if (ret) {
404 kobject_uevent(&q->kobj, KOBJ_REMOVE);
405 kobject_del(&q->kobj);
406 return ret;
407 }
408
409 return 0;
410 }
411
blk_unregister_queue(struct gendisk * disk)412 void blk_unregister_queue(struct gendisk *disk)
413 {
414 struct request_queue *q = disk->queue;
415
416 if (WARN_ON(!q))
417 return;
418
419 if (q->request_fn) {
420 elv_unregister_queue(q);
421
422 kobject_uevent(&q->kobj, KOBJ_REMOVE);
423 kobject_del(&q->kobj);
424 kobject_put(&disk_to_dev(disk)->kobj);
425 }
426 }
427