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[net-next-2.6.git] / block / blk-cgroup.c
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31e4c28d
VG		 1/*
2 * Common Block IO controller cgroup interface
3 *
4 * Based on ideas and code from CFQ, CFS and BFQ:
5 * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
6 *
7 * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
8 * Paolo Valente <paolo.valente@unimore.it>
9 *
10 * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
11 * Nauman Rafique <nauman@google.com>
12 */
13#include <linux/ioprio.h>
22084190
VG		 14#include <linux/seq_file.h>
15#include <linux/kdev_t.h>
9d6a986c 16#include <linux/module.h>
accee785 17#include <linux/err.h>
9195291e 18#include <linux/blkdev.h>
5a0e3ad6 19#include <linux/slab.h>
31e4c28d 20#include "blk-cgroup.h"
34d0f179 21#include <linux/genhd.h>
3e252066 22
84c124da
DS		 23#define MAX_KEY_LEN 100
24
3e252066
VG		 25static DEFINE_SPINLOCK(blkio_list_lock);
26static LIST_HEAD(blkio_list);
b1c35769 27
31e4c28d 28struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
9d6a986c
VG		 29EXPORT_SYMBOL_GPL(blkio_root_cgroup);
30
67523c48
BB		 31static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
32 struct cgroup *);
33static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,
34 struct task_struct *, bool);
35static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *,
36 struct cgroup *, struct task_struct *, bool);
37static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);
38static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);
39
062a644d
VG		 40/* for encoding cft->private value on file */
41#define BLKIOFILE_PRIVATE(x, val) (((x) << 16) | (val))
42/* What policy owns the file, proportional or throttle */
43#define BLKIOFILE_POLICY(val) (((val) >> 16) & 0xffff)
44#define BLKIOFILE_ATTR(val) ((val) & 0xffff)
45
67523c48
BB		 46struct cgroup_subsys blkio_subsys = {
47 .name = "blkio",
48 .create = blkiocg_create,
49 .can_attach = blkiocg_can_attach,
50 .attach = blkiocg_attach,
51 .destroy = blkiocg_destroy,
52 .populate = blkiocg_populate,
53#ifdef CONFIG_BLK_CGROUP
54 /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */
55 .subsys_id = blkio_subsys_id,
56#endif
57 .use_id = 1,
58 .module = THIS_MODULE,
59};
60EXPORT_SYMBOL_GPL(blkio_subsys);
61
34d0f179
GJ		 62static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg,
63 struct blkio_policy_node *pn)
64{
65 list_add(&pn->node, &blkcg->policy_list);
66}
67
062a644d
VG		 68static inline bool cftype_blkg_same_policy(struct cftype *cft,
69 struct blkio_group *blkg)
70{
71 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
72
73 if (blkg->plid == plid)
74 return 1;
75
76 return 0;
77}
78
79/* Determines if policy node matches cgroup file being accessed */
80static inline bool pn_matches_cftype(struct cftype *cft,
81 struct blkio_policy_node *pn)
82{
83 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
84 int fileid = BLKIOFILE_ATTR(cft->private);
85
86 return (plid == pn->plid && fileid == pn->fileid);
87}
88
34d0f179
GJ		 89/* Must be called with blkcg->lock held */
90static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)
91{
92 list_del(&pn->node);
93}
94
95/* Must be called with blkcg->lock held */
96static struct blkio_policy_node *
062a644d
VG		 97blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev,
98 enum blkio_policy_id plid, int fileid)
34d0f179
GJ		 99{
100 struct blkio_policy_node *pn;
101
102 list_for_each_entry(pn, &blkcg->policy_list, node) {
062a644d 103 if (pn->dev == dev && pn->plid == plid && pn->fileid == fileid)
34d0f179
GJ		 104 return pn;
105 }
106
107 return NULL;
108}
109
31e4c28d
VG		 110struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
111{
112 return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
113 struct blkio_cgroup, css);
114}
9d6a986c 115EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
31e4c28d 116
062a644d
VG		 117static inline void
118blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight)
119{
120 struct blkio_policy_type *blkiop;
121
122 list_for_each_entry(blkiop, &blkio_list, list) {
123 /* If this policy does not own the blkg, do not send updates */
124 if (blkiop->plid != blkg->plid)
125 continue;
126 if (blkiop->ops.blkio_update_group_weight_fn)
fe071437
VG		 127 blkiop->ops.blkio_update_group_weight_fn(blkg->key,
128 blkg, weight);
062a644d
VG		 129 }
130}
131
4c9eefa1
VG		 132static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps,
133 int fileid)
134{
135 struct blkio_policy_type *blkiop;
136
137 list_for_each_entry(blkiop, &blkio_list, list) {
138
139 /* If this policy does not own the blkg, do not send updates */
140 if (blkiop->plid != blkg->plid)
141 continue;
142
143 if (fileid == BLKIO_THROTL_read_bps_device
144 && blkiop->ops.blkio_update_group_read_bps_fn)
fe071437
VG		 145 blkiop->ops.blkio_update_group_read_bps_fn(blkg->key,
146 blkg, bps);
4c9eefa1
VG		 147
148 if (fileid == BLKIO_THROTL_write_bps_device
149 && blkiop->ops.blkio_update_group_write_bps_fn)
fe071437
VG		 150 blkiop->ops.blkio_update_group_write_bps_fn(blkg->key,
151 blkg, bps);
4c9eefa1
VG		 152 }
153}
154
7702e8f4
VG		 155static inline void blkio_update_group_iops(struct blkio_group *blkg,
156 unsigned int iops, int fileid)
157{
158 struct blkio_policy_type *blkiop;
159
160 list_for_each_entry(blkiop, &blkio_list, list) {
161
162 /* If this policy does not own the blkg, do not send updates */
163 if (blkiop->plid != blkg->plid)
164 continue;
165
166 if (fileid == BLKIO_THROTL_read_iops_device
167 && blkiop->ops.blkio_update_group_read_iops_fn)
fe071437
VG		 168 blkiop->ops.blkio_update_group_read_iops_fn(blkg->key,
169 blkg, iops);
7702e8f4
VG		 170
171 if (fileid == BLKIO_THROTL_write_iops_device
172 && blkiop->ops.blkio_update_group_write_iops_fn)
fe071437
VG		 173 blkiop->ops.blkio_update_group_write_iops_fn(blkg->key,
174 blkg,iops);
7702e8f4
VG		 175 }
176}
177
9195291e
DS		 178/*
179 * Add to the appropriate stat variable depending on the request type.
180 * This should be called with the blkg->stats_lock held.
181 */
84c124da
DS		 182static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction,
183 bool sync)
9195291e 184{
84c124da
DS		 185 if (direction)
186 stat[BLKIO_STAT_WRITE] += add;
9195291e 187 else
84c124da
DS		 188 stat[BLKIO_STAT_READ] += add;
189 if (sync)
190 stat[BLKIO_STAT_SYNC] += add;
9195291e 191 else
84c124da 192 stat[BLKIO_STAT_ASYNC] += add;
9195291e
DS		 193}
194
cdc1184c
DS		 195/*
196 * Decrements the appropriate stat variable if non-zero depending on the
197 * request type. Panics on value being zero.
198 * This should be called with the blkg->stats_lock held.
199 */
200static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync)
201{
202 if (direction) {
203 BUG_ON(stat[BLKIO_STAT_WRITE] == 0);
204 stat[BLKIO_STAT_WRITE]--;
205 } else {
206 BUG_ON(stat[BLKIO_STAT_READ] == 0);
207 stat[BLKIO_STAT_READ]--;
208 }
209 if (sync) {
210 BUG_ON(stat[BLKIO_STAT_SYNC] == 0);
211 stat[BLKIO_STAT_SYNC]--;
212 } else {
213 BUG_ON(stat[BLKIO_STAT_ASYNC] == 0);
214 stat[BLKIO_STAT_ASYNC]--;
215 }
216}
217
218#ifdef CONFIG_DEBUG_BLK_CGROUP
812df48d
DS		 219/* This should be called with the blkg->stats_lock held. */
220static void blkio_set_start_group_wait_time(struct blkio_group *blkg,
221 struct blkio_group *curr_blkg)
222{
223 if (blkio_blkg_waiting(&blkg->stats))
224 return;
225 if (blkg == curr_blkg)
226 return;
227 blkg->stats.start_group_wait_time = sched_clock();
228 blkio_mark_blkg_waiting(&blkg->stats);
229}
230
231/* This should be called with the blkg->stats_lock held. */
232static void blkio_update_group_wait_time(struct blkio_group_stats *stats)
233{
234 unsigned long long now;
235
236 if (!blkio_blkg_waiting(stats))
237 return;
238
239 now = sched_clock();
240 if (time_after64(now, stats->start_group_wait_time))
241 stats->group_wait_time += now - stats->start_group_wait_time;
242 blkio_clear_blkg_waiting(stats);
243}
244
245/* This should be called with the blkg->stats_lock held. */
246static void blkio_end_empty_time(struct blkio_group_stats *stats)
247{
248 unsigned long long now;
249
250 if (!blkio_blkg_empty(stats))
251 return;
252
253 now = sched_clock();
254 if (time_after64(now, stats->start_empty_time))
255 stats->empty_time += now - stats->start_empty_time;
256 blkio_clear_blkg_empty(stats);
257}
258
259void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
260{
261 unsigned long flags;
262
263 spin_lock_irqsave(&blkg->stats_lock, flags);
264 BUG_ON(blkio_blkg_idling(&blkg->stats));
265 blkg->stats.start_idle_time = sched_clock();
266 blkio_mark_blkg_idling(&blkg->stats);
267 spin_unlock_irqrestore(&blkg->stats_lock, flags);
268}
269EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats);
270
271void blkiocg_update_idle_time_stats(struct blkio_group *blkg)
272{
273 unsigned long flags;
274 unsigned long long now;
275 struct blkio_group_stats *stats;
276
277 spin_lock_irqsave(&blkg->stats_lock, flags);
278 stats = &blkg->stats;
279 if (blkio_blkg_idling(stats)) {
280 now = sched_clock();
281 if (time_after64(now, stats->start_idle_time))
282 stats->idle_time += now - stats->start_idle_time;
283 blkio_clear_blkg_idling(stats);
284 }
285 spin_unlock_irqrestore(&blkg->stats_lock, flags);
286}
287EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats);
288
a11cdaa7 289void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg)
cdc1184c
DS		 290{
291 unsigned long flags;
292 struct blkio_group_stats *stats;
293
294 spin_lock_irqsave(&blkg->stats_lock, flags);
295 stats = &blkg->stats;
296 stats->avg_queue_size_sum +=
297 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] +
298 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE];
299 stats->avg_queue_size_samples++;
812df48d 300 blkio_update_group_wait_time(stats);
cdc1184c
DS		 301 spin_unlock_irqrestore(&blkg->stats_lock, flags);
302}
a11cdaa7
DS		 303EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats);
304
e5ff082e 305void blkiocg_set_start_empty_time(struct blkio_group *blkg)
28baf442
DS		 306{
307 unsigned long flags;
308 struct blkio_group_stats *stats;
309
310 spin_lock_irqsave(&blkg->stats_lock, flags);
311 stats = &blkg->stats;
312
313 if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] ||
314 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) {
315 spin_unlock_irqrestore(&blkg->stats_lock, flags);
316 return;
317 }
318
319 /*
e5ff082e
VG		 320 * group is already marked empty. This can happen if cfqq got new
321 * request in parent group and moved to this group while being added
322 * to service tree. Just ignore the event and move on.
28baf442 323 */
e5ff082e
VG		 324 if(blkio_blkg_empty(stats)) {
325 spin_unlock_irqrestore(&blkg->stats_lock, flags);
326 return;
327 }
328
28baf442
DS		 329 stats->start_empty_time = sched_clock();
330 blkio_mark_blkg_empty(stats);
331 spin_unlock_irqrestore(&blkg->stats_lock, flags);
332}
333EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time);
334
a11cdaa7
DS		 335void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
336 unsigned long dequeue)
337{
338 blkg->stats.dequeue += dequeue;
339}
340EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats);
812df48d
DS		 341#else
342static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg,
343 struct blkio_group *curr_blkg) {}
344static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {}
cdc1184c
DS		 345#endif
346
a11cdaa7 347void blkiocg_update_io_add_stats(struct blkio_group *blkg,
cdc1184c
DS		 348 struct blkio_group *curr_blkg, bool direction,
349 bool sync)
350{
351 unsigned long flags;
352
353 spin_lock_irqsave(&blkg->stats_lock, flags);
354 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction,
355 sync);
812df48d
DS		 356 blkio_end_empty_time(&blkg->stats);
357 blkio_set_start_group_wait_time(blkg, curr_blkg);
cdc1184c
DS		 358 spin_unlock_irqrestore(&blkg->stats_lock, flags);
359}
a11cdaa7 360EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats);
cdc1184c 361
a11cdaa7 362void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
cdc1184c
DS		 363 bool direction, bool sync)
364{
365 unsigned long flags;
366
367 spin_lock_irqsave(&blkg->stats_lock, flags);
368 blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED],
369 direction, sync);
370 spin_unlock_irqrestore(&blkg->stats_lock, flags);
371}
a11cdaa7 372EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats);
cdc1184c 373
303a3acb 374void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time)
22084190 375{
303a3acb
DS		 376 unsigned long flags;
377
378 spin_lock_irqsave(&blkg->stats_lock, flags);
379 blkg->stats.time += time;
380 spin_unlock_irqrestore(&blkg->stats_lock, flags);
22084190 381}
303a3acb 382EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
22084190 383
84c124da
DS		 384void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
385 uint64_t bytes, bool direction, bool sync)
9195291e
DS		 386{
387 struct blkio_group_stats *stats;
388 unsigned long flags;
389
390 spin_lock_irqsave(&blkg->stats_lock, flags);
391 stats = &blkg->stats;
84c124da
DS		 392 stats->sectors += bytes >> 9;
393 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction,
394 sync);
395 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes,
396 direction, sync);
9195291e
DS		 397 spin_unlock_irqrestore(&blkg->stats_lock, flags);
398}
84c124da 399EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
9195291e 400
84c124da
DS		 401void blkiocg_update_completion_stats(struct blkio_group *blkg,
402 uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
9195291e
DS		 403{
404 struct blkio_group_stats *stats;
405 unsigned long flags;
406 unsigned long long now = sched_clock();
407
408 spin_lock_irqsave(&blkg->stats_lock, flags);
409 stats = &blkg->stats;
84c124da
DS		 410 if (time_after64(now, io_start_time))
411 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME],
412 now - io_start_time, direction, sync);
413 if (time_after64(io_start_time, start_time))
414 blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME],
415 io_start_time - start_time, direction, sync);
9195291e
DS		 416 spin_unlock_irqrestore(&blkg->stats_lock, flags);
417}
84c124da 418EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
9195291e 419
812d4026
DS		 420void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
421 bool sync)
422{
423 unsigned long flags;
424
425 spin_lock_irqsave(&blkg->stats_lock, flags);
426 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction,
427 sync);
428 spin_unlock_irqrestore(&blkg->stats_lock, flags);
429}
430EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
431
31e4c28d 432void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
062a644d
VG		 433 struct blkio_group *blkg, void *key, dev_t dev,
434 enum blkio_policy_id plid)
31e4c28d
VG		 435{
436 unsigned long flags;
437
438 spin_lock_irqsave(&blkcg->lock, flags);
8d2a91f8 439 spin_lock_init(&blkg->stats_lock);
31e4c28d 440 rcu_assign_pointer(blkg->key, key);
b1c35769 441 blkg->blkcg_id = css_id(&blkcg->css);
31e4c28d 442 hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
062a644d 443 blkg->plid = plid;
31e4c28d 444 spin_unlock_irqrestore(&blkcg->lock, flags);
2868ef7b
VG		 445 /* Need to take css reference ? */
446 cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
22084190 447 blkg->dev = dev;
31e4c28d 448}
9d6a986c 449EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group);
31e4c28d 450
b1c35769
VG		 451static void __blkiocg_del_blkio_group(struct blkio_group *blkg)
452{
453 hlist_del_init_rcu(&blkg->blkcg_node);
454 blkg->blkcg_id = 0;
455}
456
457/*
458 * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1
459 * indicating that blk_group was unhashed by the time we got to it.
460 */
31e4c28d
VG		 461int blkiocg_del_blkio_group(struct blkio_group *blkg)
462{
b1c35769
VG		 463 struct blkio_cgroup *blkcg;
464 unsigned long flags;
465 struct cgroup_subsys_state *css;
466 int ret = 1;
467
468 rcu_read_lock();
469 css = css_lookup(&blkio_subsys, blkg->blkcg_id);
0f3942a3
JA		 470 if (css) {
471 blkcg = container_of(css, struct blkio_cgroup, css);
472 spin_lock_irqsave(&blkcg->lock, flags);
473 if (!hlist_unhashed(&blkg->blkcg_node)) {
474 __blkiocg_del_blkio_group(blkg);
475 ret = 0;
476 }
477 spin_unlock_irqrestore(&blkcg->lock, flags);
b1c35769 478 }
0f3942a3 479
b1c35769
VG		 480 rcu_read_unlock();
481 return ret;
31e4c28d 482}
9d6a986c 483EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group);
31e4c28d
VG		 484
485/* called under rcu_read_lock(). */
486struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
487{
488 struct blkio_group *blkg;
489 struct hlist_node *n;
490 void *__key;
491
492 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
493 __key = blkg->key;
494 if (__key == key)
495 return blkg;
496 }
497
498 return NULL;
499}
9d6a986c 500EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
31e4c28d 501
303a3acb 502static int
84c124da 503blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
303a3acb
DS		 504{
505 struct blkio_cgroup *blkcg;
506 struct blkio_group *blkg;
812df48d 507 struct blkio_group_stats *stats;
303a3acb 508 struct hlist_node *n;
cdc1184c
DS		 509 uint64_t queued[BLKIO_STAT_TOTAL];
510 int i;
812df48d
DS		 511#ifdef CONFIG_DEBUG_BLK_CGROUP
512 bool idling, waiting, empty;
513 unsigned long long now = sched_clock();
514#endif
303a3acb
DS		 515
516 blkcg = cgroup_to_blkio_cgroup(cgroup);
517 spin_lock_irq(&blkcg->lock);
518 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
519 spin_lock(&blkg->stats_lock);
812df48d
DS		 520 stats = &blkg->stats;
521#ifdef CONFIG_DEBUG_BLK_CGROUP
522 idling = blkio_blkg_idling(stats);
523 waiting = blkio_blkg_waiting(stats);
524 empty = blkio_blkg_empty(stats);
525#endif
cdc1184c 526 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
812df48d
DS		 527 queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i];
528 memset(stats, 0, sizeof(struct blkio_group_stats));
cdc1184c 529 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
812df48d
DS		 530 stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i];
531#ifdef CONFIG_DEBUG_BLK_CGROUP
532 if (idling) {
533 blkio_mark_blkg_idling(stats);
534 stats->start_idle_time = now;
535 }
536 if (waiting) {
537 blkio_mark_blkg_waiting(stats);
538 stats->start_group_wait_time = now;
539 }
540 if (empty) {
541 blkio_mark_blkg_empty(stats);
542 stats->start_empty_time = now;
543 }
544#endif
303a3acb
DS		 545 spin_unlock(&blkg->stats_lock);
546 }
547 spin_unlock_irq(&blkcg->lock);
548 return 0;
549}
550
84c124da
DS		 551static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str,
552 int chars_left, bool diskname_only)
303a3acb 553{
84c124da 554 snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev));
303a3acb
DS		 555 chars_left -= strlen(str);
556 if (chars_left <= 0) {
557 printk(KERN_WARNING
558 "Possibly incorrect cgroup stat display format");
559 return;
560 }
84c124da
DS		 561 if (diskname_only)
562 return;
303a3acb 563 switch (type) {
84c124da 564 case BLKIO_STAT_READ:
303a3acb
DS		 565 strlcat(str, " Read", chars_left);
566 break;
84c124da 567 case BLKIO_STAT_WRITE:
303a3acb
DS		 568 strlcat(str, " Write", chars_left);
569 break;
84c124da 570 case BLKIO_STAT_SYNC:
303a3acb
DS		 571 strlcat(str, " Sync", chars_left);
572 break;
84c124da 573 case BLKIO_STAT_ASYNC:
303a3acb
DS		 574 strlcat(str, " Async", chars_left);
575 break;
84c124da 576 case BLKIO_STAT_TOTAL:
303a3acb
DS		 577 strlcat(str, " Total", chars_left);
578 break;
579 default:
580 strlcat(str, " Invalid", chars_left);
581 }
582}
583
84c124da
DS		 584static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val,
585 struct cgroup_map_cb *cb, dev_t dev)
586{
587 blkio_get_key_name(0, dev, str, chars_left, true);
588 cb->fill(cb, str, val);
589 return val;
590}
303a3acb 591
84c124da
DS		 592/* This should be called with blkg->stats_lock held */
593static uint64_t blkio_get_stat(struct blkio_group *blkg,
594 struct cgroup_map_cb *cb, dev_t dev, enum stat_type type)
303a3acb
DS		 595{
596 uint64_t disk_total;
597 char key_str[MAX_KEY_LEN];
84c124da
DS		 598 enum stat_sub_type sub_type;
599
600 if (type == BLKIO_STAT_TIME)
601 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
602 blkg->stats.time, cb, dev);
603 if (type == BLKIO_STAT_SECTORS)
604 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
605 blkg->stats.sectors, cb, dev);
606#ifdef CONFIG_DEBUG_BLK_CGROUP
cdc1184c
DS		 607 if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
608 uint64_t sum = blkg->stats.avg_queue_size_sum;
609 uint64_t samples = blkg->stats.avg_queue_size_samples;
610 if (samples)
611 do_div(sum, samples);
612 else
613 sum = 0;
614 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev);
615 }
812df48d
DS		 616 if (type == BLKIO_STAT_GROUP_WAIT_TIME)
617 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
618 blkg->stats.group_wait_time, cb, dev);
619 if (type == BLKIO_STAT_IDLE_TIME)
620 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
621 blkg->stats.idle_time, cb, dev);
622 if (type == BLKIO_STAT_EMPTY_TIME)
623 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
624 blkg->stats.empty_time, cb, dev);
84c124da
DS		 625 if (type == BLKIO_STAT_DEQUEUE)
626 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
627 blkg->stats.dequeue, cb, dev);
628#endif
303a3acb 629
84c124da
DS		 630 for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
631 sub_type++) {
632 blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
633 cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]);
303a3acb 634 }
84c124da
DS		 635 disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] +
636 blkg->stats.stat_arr[type][BLKIO_STAT_WRITE];
637 blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
303a3acb
DS		 638 cb->fill(cb, key_str, disk_total);
639 return disk_total;
640}
641
34d0f179
GJ		 642static int blkio_check_dev_num(dev_t dev)
643{
644 int part = 0;
645 struct gendisk *disk;
646
647 disk = get_gendisk(dev, &part);
648 if (!disk || part)
649 return -ENODEV;
650
651 return 0;
652}
653
654static int blkio_policy_parse_and_set(char *buf,
062a644d 655 struct blkio_policy_node *newpn, enum blkio_policy_id plid, int fileid)
34d0f179
GJ		 656{
657 char *s[4], *p, *major_s = NULL, *minor_s = NULL;
658 int ret;
659 unsigned long major, minor, temp;
660 int i = 0;
661 dev_t dev;
9355aede 662 u64 bps, iops;
34d0f179
GJ		 663
664 memset(s, 0, sizeof(s));
665
666 while ((p = strsep(&buf, " ")) != NULL) {
667 if (!*p)
668 continue;
669
670 s[i++] = p;
671
672 /* Prevent from inputing too many things */
673 if (i == 3)
674 break;
675 }
676
677 if (i != 2)
678 return -EINVAL;
679
680 p = strsep(&s[0], ":");
681 if (p != NULL)
682 major_s = p;
683 else
684 return -EINVAL;
685
686 minor_s = s[0];
687 if (!minor_s)
688 return -EINVAL;
689
690 ret = strict_strtoul(major_s, 10, &major);
691 if (ret)
692 return -EINVAL;
693
694 ret = strict_strtoul(minor_s, 10, &minor);
695 if (ret)
696 return -EINVAL;
697
698 dev = MKDEV(major, minor);
699
700 ret = blkio_check_dev_num(dev);
701 if (ret)
702 return ret;
703
704 newpn->dev = dev;
705
706 if (s[1] == NULL)
707 return -EINVAL;
708
062a644d
VG		 709 switch (plid) {
710 case BLKIO_POLICY_PROP:
711 ret = strict_strtoul(s[1], 10, &temp);
712 if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
713 temp > BLKIO_WEIGHT_MAX)
714 return -EINVAL;
34d0f179 715
062a644d
VG		 716 newpn->plid = plid;
717 newpn->fileid = fileid;
4c9eefa1
VG		 718 newpn->val.weight = temp;
719 break;
720 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 721 switch(fileid) {
722 case BLKIO_THROTL_read_bps_device:
723 case BLKIO_THROTL_write_bps_device:
724 ret = strict_strtoull(s[1], 10, &bps);
725 if (ret)
726 return -EINVAL;
4c9eefa1 727
7702e8f4
VG		 728 newpn->plid = plid;
729 newpn->fileid = fileid;
730 newpn->val.bps = bps;
731 break;
732 case BLKIO_THROTL_read_iops_device:
733 case BLKIO_THROTL_write_iops_device:
9355aede 734 ret = strict_strtoull(s[1], 10, &iops);
7702e8f4
VG		 735 if (ret)
736 return -EINVAL;
737
9355aede
VG		 738 if (iops > THROTL_IOPS_MAX)
739 return -EINVAL;
740
7702e8f4
VG		 741 newpn->plid = plid;
742 newpn->fileid = fileid;
9355aede 743 newpn->val.iops = (unsigned int)iops;
7702e8f4
VG		 744 break;
745 }
062a644d
VG		 746 break;
747 default:
748 BUG();
749 }
34d0f179
GJ		 750
751 return 0;
752}
753
754unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
755 dev_t dev)
756{
757 struct blkio_policy_node *pn;
758
062a644d
VG		 759 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_PROP,
760 BLKIO_PROP_weight_device);
34d0f179 761 if (pn)
4c9eefa1 762 return pn->val.weight;
34d0f179
GJ		 763 else
764 return blkcg->weight;
765}
766EXPORT_SYMBOL_GPL(blkcg_get_weight);
767
4c9eefa1
VG		 768uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev)
769{
770 struct blkio_policy_node *pn;
771
772 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
773 BLKIO_THROTL_read_bps_device);
774 if (pn)
775 return pn->val.bps;
776 else
777 return -1;
778}
779
780uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev)
781{
782 struct blkio_policy_node *pn;
783 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
784 BLKIO_THROTL_write_bps_device);
785 if (pn)
786 return pn->val.bps;
787 else
788 return -1;
789}
790
7702e8f4
VG		 791unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, dev_t dev)
792{
793 struct blkio_policy_node *pn;
794
795 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
796 BLKIO_THROTL_read_iops_device);
797 if (pn)
798 return pn->val.iops;
799 else
800 return -1;
801}
802
803unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev)
804{
805 struct blkio_policy_node *pn;
806 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
807 BLKIO_THROTL_write_iops_device);
808 if (pn)
809 return pn->val.iops;
810 else
811 return -1;
812}
813
062a644d
VG		 814/* Checks whether user asked for deleting a policy rule */
815static bool blkio_delete_rule_command(struct blkio_policy_node *pn)
816{
817 switch(pn->plid) {
818 case BLKIO_POLICY_PROP:
4c9eefa1
VG		 819 if (pn->val.weight == 0)
820 return 1;
821 break;
822 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 823 switch(pn->fileid) {
824 case BLKIO_THROTL_read_bps_device:
825 case BLKIO_THROTL_write_bps_device:
826 if (pn->val.bps == 0)
827 return 1;
828 break;
829 case BLKIO_THROTL_read_iops_device:
830 case BLKIO_THROTL_write_iops_device:
831 if (pn->val.iops == 0)
832 return 1;
833 }
062a644d
VG		 834 break;
835 default:
836 BUG();
837 }
838
839 return 0;
840}
841
842static void blkio_update_policy_rule(struct blkio_policy_node *oldpn,
843 struct blkio_policy_node *newpn)
844{
845 switch(oldpn->plid) {
846 case BLKIO_POLICY_PROP:
4c9eefa1
VG		 847 oldpn->val.weight = newpn->val.weight;
848 break;
849 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 850 switch(newpn->fileid) {
851 case BLKIO_THROTL_read_bps_device:
852 case BLKIO_THROTL_write_bps_device:
853 oldpn->val.bps = newpn->val.bps;
854 break;
855 case BLKIO_THROTL_read_iops_device:
856 case BLKIO_THROTL_write_iops_device:
857 oldpn->val.iops = newpn->val.iops;
858 }
062a644d
VG		 859 break;
860 default:
861 BUG();
862 }
863}
864
865/*
866 * Some rules/values in blkg have changed. Propogate those to respective
867 * policies.
868 */
869static void blkio_update_blkg_policy(struct blkio_cgroup *blkcg,
870 struct blkio_group *blkg, struct blkio_policy_node *pn)
871{
7702e8f4 872 unsigned int weight, iops;
4c9eefa1 873 u64 bps;
062a644d
VG		 874
875 switch(pn->plid) {
876 case BLKIO_POLICY_PROP:
4c9eefa1 877 weight = pn->val.weight ? pn->val.weight :
062a644d
VG		 878 blkcg->weight;
879 blkio_update_group_weight(blkg, weight);
880 break;
4c9eefa1
VG		 881 case BLKIO_POLICY_THROTL:
882 switch(pn->fileid) {
883 case BLKIO_THROTL_read_bps_device:
884 case BLKIO_THROTL_write_bps_device:
885 bps = pn->val.bps ? pn->val.bps : (-1);
886 blkio_update_group_bps(blkg, bps, pn->fileid);
887 break;
7702e8f4
VG		 888 case BLKIO_THROTL_read_iops_device:
889 case BLKIO_THROTL_write_iops_device:
890 iops = pn->val.iops ? pn->val.iops : (-1);
891 blkio_update_group_iops(blkg, iops, pn->fileid);
892 break;
4c9eefa1
VG		 893 }
894 break;
062a644d
VG		 895 default:
896 BUG();
897 }
898}
899
900/*
901 * A policy node rule has been updated. Propogate this update to all the
902 * block groups which might be affected by this update.
903 */
904static void blkio_update_policy_node_blkg(struct blkio_cgroup *blkcg,
905 struct blkio_policy_node *pn)
906{
907 struct blkio_group *blkg;
908 struct hlist_node *n;
909
910 spin_lock(&blkio_list_lock);
911 spin_lock_irq(&blkcg->lock);
34d0f179 912
062a644d
VG		 913 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
914 if (pn->dev != blkg->dev || pn->plid != blkg->plid)
915 continue;
916 blkio_update_blkg_policy(blkcg, blkg, pn);
917 }
918
919 spin_unlock_irq(&blkcg->lock);
920 spin_unlock(&blkio_list_lock);
921}
34d0f179 922
062a644d
VG		 923static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft,
924 const char *buffer)
34d0f179
GJ		 925{
926 int ret = 0;
927 char *buf;
928 struct blkio_policy_node *newpn, *pn;
929 struct blkio_cgroup *blkcg;
34d0f179 930 int keep_newpn = 0;
062a644d
VG		 931 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
932 int fileid = BLKIOFILE_ATTR(cft->private);
34d0f179
GJ		 933
934 buf = kstrdup(buffer, GFP_KERNEL);
935 if (!buf)
936 return -ENOMEM;
937
938 newpn = kzalloc(sizeof(*newpn), GFP_KERNEL);
939 if (!newpn) {
940 ret = -ENOMEM;
941 goto free_buf;
942 }
943
062a644d 944 ret = blkio_policy_parse_and_set(buf, newpn, plid, fileid);
34d0f179
GJ		 945 if (ret)
946 goto free_newpn;
947
948 blkcg = cgroup_to_blkio_cgroup(cgrp);
949
950 spin_lock_irq(&blkcg->lock);
951
062a644d 952 pn = blkio_policy_search_node(blkcg, newpn->dev, plid, fileid);
34d0f179 953 if (!pn) {
062a644d 954 if (!blkio_delete_rule_command(newpn)) {
34d0f179
GJ		 955 blkio_policy_insert_node(blkcg, newpn);
956 keep_newpn = 1;
957 }
958 spin_unlock_irq(&blkcg->lock);
959 goto update_io_group;
960 }
961
062a644d 962 if (blkio_delete_rule_command(newpn)) {
34d0f179
GJ		 963 blkio_policy_delete_node(pn);
964 spin_unlock_irq(&blkcg->lock);
965 goto update_io_group;
966 }
967 spin_unlock_irq(&blkcg->lock);
968
062a644d 969 blkio_update_policy_rule(pn, newpn);
34d0f179
GJ		 970
971update_io_group:
062a644d 972 blkio_update_policy_node_blkg(blkcg, newpn);
34d0f179
GJ		 973
974free_newpn:
975 if (!keep_newpn)
976 kfree(newpn);
977free_buf:
978 kfree(buf);
979 return ret;
980}
981
062a644d
VG		 982static void
983blkio_print_policy_node(struct seq_file *m, struct blkio_policy_node *pn)
34d0f179 984{
062a644d
VG		 985 switch(pn->plid) {
986 case BLKIO_POLICY_PROP:
987 if (pn->fileid == BLKIO_PROP_weight_device)
988 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
4c9eefa1
VG		 989 MINOR(pn->dev), pn->val.weight);
990 break;
991 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 992 switch(pn->fileid) {
993 case BLKIO_THROTL_read_bps_device:
994 case BLKIO_THROTL_write_bps_device:
4c9eefa1
VG		 995 seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev),
996 MINOR(pn->dev), pn->val.bps);
7702e8f4
VG		 997 break;
998 case BLKIO_THROTL_read_iops_device:
999 case BLKIO_THROTL_write_iops_device:
1000 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
1001 MINOR(pn->dev), pn->val.iops);
1002 break;
1003 }
062a644d
VG		 1004 break;
1005 default:
1006 BUG();
1007 }
1008}
34d0f179 1009
062a644d
VG		 1010/* cgroup files which read their data from policy nodes end up here */
1011static void blkio_read_policy_node_files(struct cftype *cft,
1012 struct blkio_cgroup *blkcg, struct seq_file *m)
34d0f179 1013{
34d0f179 1014 struct blkio_policy_node *pn;
34d0f179 1015
0f3942a3
JA		 1016 if (!list_empty(&blkcg->policy_list)) {
1017 spin_lock_irq(&blkcg->lock);
1018 list_for_each_entry(pn, &blkcg->policy_list, node) {
062a644d
VG		 1019 if (!pn_matches_cftype(cft, pn))
1020 continue;
1021 blkio_print_policy_node(m, pn);
0f3942a3
JA		 1022 }
1023 spin_unlock_irq(&blkcg->lock);
34d0f179 1024 }
062a644d
VG		 1025}
1026
1027static int blkiocg_file_read(struct cgroup *cgrp, struct cftype *cft,
1028 struct seq_file *m)
1029{
1030 struct blkio_cgroup *blkcg;
1031 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1032 int name = BLKIOFILE_ATTR(cft->private);
1033
1034 blkcg = cgroup_to_blkio_cgroup(cgrp);
1035
1036 switch(plid) {
1037 case BLKIO_POLICY_PROP:
1038 switch(name) {
1039 case BLKIO_PROP_weight_device:
1040 blkio_read_policy_node_files(cft, blkcg, m);
1041 return 0;
1042 default:
1043 BUG();
1044 }
1045 break;
4c9eefa1
VG		 1046 case BLKIO_POLICY_THROTL:
1047 switch(name){
1048 case BLKIO_THROTL_read_bps_device:
1049 case BLKIO_THROTL_write_bps_device:
7702e8f4
VG		 1050 case BLKIO_THROTL_read_iops_device:
1051 case BLKIO_THROTL_write_iops_device:
4c9eefa1
VG		 1052 blkio_read_policy_node_files(cft, blkcg, m);
1053 return 0;
1054 default:
1055 BUG();
1056 }
1057 break;
062a644d
VG		 1058 default:
1059 BUG();
1060 }
1061
1062 return 0;
1063}
1064
1065static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
1066 struct cftype *cft, struct cgroup_map_cb *cb, enum stat_type type,
1067 bool show_total)
1068{
1069 struct blkio_group *blkg;
1070 struct hlist_node *n;
1071 uint64_t cgroup_total = 0;
1072
1073 rcu_read_lock();
1074 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
1075 if (blkg->dev) {
1076 if (!cftype_blkg_same_policy(cft, blkg))
1077 continue;
1078 spin_lock_irq(&blkg->stats_lock);
1079 cgroup_total += blkio_get_stat(blkg, cb, blkg->dev,
1080 type);
1081 spin_unlock_irq(&blkg->stats_lock);
1082 }
1083 }
1084 if (show_total)
1085 cb->fill(cb, "Total", cgroup_total);
1086 rcu_read_unlock();
1087 return 0;
1088}
1089
1090/* All map kind of cgroup file get serviced by this function */
1091static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft,
1092 struct cgroup_map_cb *cb)
1093{
1094 struct blkio_cgroup *blkcg;
1095 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1096 int name = BLKIOFILE_ATTR(cft->private);
1097
1098 blkcg = cgroup_to_blkio_cgroup(cgrp);
1099
1100 switch(plid) {
1101 case BLKIO_POLICY_PROP:
1102 switch(name) {
1103 case BLKIO_PROP_time:
1104 return blkio_read_blkg_stats(blkcg, cft, cb,
1105 BLKIO_STAT_TIME, 0);
1106 case BLKIO_PROP_sectors:
1107 return blkio_read_blkg_stats(blkcg, cft, cb,
1108 BLKIO_STAT_SECTORS, 0);
1109 case BLKIO_PROP_io_service_bytes:
1110 return blkio_read_blkg_stats(blkcg, cft, cb,
1111 BLKIO_STAT_SERVICE_BYTES, 1);
1112 case BLKIO_PROP_io_serviced:
1113 return blkio_read_blkg_stats(blkcg, cft, cb,
1114 BLKIO_STAT_SERVICED, 1);
1115 case BLKIO_PROP_io_service_time:
1116 return blkio_read_blkg_stats(blkcg, cft, cb,
1117 BLKIO_STAT_SERVICE_TIME, 1);
1118 case BLKIO_PROP_io_wait_time:
1119 return blkio_read_blkg_stats(blkcg, cft, cb,
1120 BLKIO_STAT_WAIT_TIME, 1);
1121 case BLKIO_PROP_io_merged:
1122 return blkio_read_blkg_stats(blkcg, cft, cb,
1123 BLKIO_STAT_MERGED, 1);
1124 case BLKIO_PROP_io_queued:
1125 return blkio_read_blkg_stats(blkcg, cft, cb,
1126 BLKIO_STAT_QUEUED, 1);
1127#ifdef CONFIG_DEBUG_BLK_CGROUP
1128 case BLKIO_PROP_dequeue:
1129 return blkio_read_blkg_stats(blkcg, cft, cb,
1130 BLKIO_STAT_DEQUEUE, 0);
1131 case BLKIO_PROP_avg_queue_size:
1132 return blkio_read_blkg_stats(blkcg, cft, cb,
1133 BLKIO_STAT_AVG_QUEUE_SIZE, 0);
1134 case BLKIO_PROP_group_wait_time:
1135 return blkio_read_blkg_stats(blkcg, cft, cb,
1136 BLKIO_STAT_GROUP_WAIT_TIME, 0);
1137 case BLKIO_PROP_idle_time:
1138 return blkio_read_blkg_stats(blkcg, cft, cb,
1139 BLKIO_STAT_IDLE_TIME, 0);
1140 case BLKIO_PROP_empty_time:
1141 return blkio_read_blkg_stats(blkcg, cft, cb,
1142 BLKIO_STAT_EMPTY_TIME, 0);
1143#endif
1144 default:
1145 BUG();
1146 }
1147 break;
4c9eefa1
VG		 1148 case BLKIO_POLICY_THROTL:
1149 switch(name){
1150 case BLKIO_THROTL_io_service_bytes:
1151 return blkio_read_blkg_stats(blkcg, cft, cb,
1152 BLKIO_STAT_SERVICE_BYTES, 1);
1153 case BLKIO_THROTL_io_serviced:
1154 return blkio_read_blkg_stats(blkcg, cft, cb,
1155 BLKIO_STAT_SERVICED, 1);
1156 default:
1157 BUG();
1158 }
1159 break;
062a644d
VG		 1160 default:
1161 BUG();
1162 }
1163
1164 return 0;
1165}
1166
1167static int blkio_weight_write(struct blkio_cgroup *blkcg, u64 val)
1168{
1169 struct blkio_group *blkg;
1170 struct hlist_node *n;
1171 struct blkio_policy_node *pn;
1172
1173 if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
1174 return -EINVAL;
1175
1176 spin_lock(&blkio_list_lock);
1177 spin_lock_irq(&blkcg->lock);
1178 blkcg->weight = (unsigned int)val;
1179
1180 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
1181 pn = blkio_policy_search_node(blkcg, blkg->dev,
1182 BLKIO_POLICY_PROP, BLKIO_PROP_weight_device);
1183 if (pn)
1184 continue;
1185
1186 blkio_update_group_weight(blkg, blkcg->weight);
1187 }
1188 spin_unlock_irq(&blkcg->lock);
1189 spin_unlock(&blkio_list_lock);
1190 return 0;
1191}
1192
1193static u64 blkiocg_file_read_u64 (struct cgroup *cgrp, struct cftype *cft) {
1194 struct blkio_cgroup *blkcg;
1195 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1196 int name = BLKIOFILE_ATTR(cft->private);
1197
1198 blkcg = cgroup_to_blkio_cgroup(cgrp);
1199
1200 switch(plid) {
1201 case BLKIO_POLICY_PROP:
1202 switch(name) {
1203 case BLKIO_PROP_weight:
1204 return (u64)blkcg->weight;
1205 }
1206 break;
1207 default:
1208 BUG();
1209 }
1210 return 0;
1211}
1212
1213static int
1214blkiocg_file_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
1215{
1216 struct blkio_cgroup *blkcg;
1217 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1218 int name = BLKIOFILE_ATTR(cft->private);
1219
1220 blkcg = cgroup_to_blkio_cgroup(cgrp);
1221
1222 switch(plid) {
1223 case BLKIO_POLICY_PROP:
1224 switch(name) {
1225 case BLKIO_PROP_weight:
1226 return blkio_weight_write(blkcg, val);
1227 }
1228 break;
1229 default:
1230 BUG();
1231 }
34d0f179 1232
34d0f179
GJ		 1233 return 0;
1234}
1235
31e4c28d 1236struct cftype blkio_files[] = {
34d0f179
GJ		 1237 {
1238 .name = "weight_device",
062a644d
VG		 1239 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1240 BLKIO_PROP_weight_device),
1241 .read_seq_string = blkiocg_file_read,
1242 .write_string = blkiocg_file_write,
34d0f179
GJ		 1243 .max_write_len = 256,
1244 },
31e4c28d
VG		 1245 {
1246 .name = "weight",
062a644d
VG		 1247 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1248 BLKIO_PROP_weight),
1249 .read_u64 = blkiocg_file_read_u64,
1250 .write_u64 = blkiocg_file_write_u64,
31e4c28d 1251 },
22084190
VG		 1252 {
1253 .name = "time",
062a644d
VG		 1254 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1255 BLKIO_PROP_time),
1256 .read_map = blkiocg_file_read_map,
22084190
VG		 1257 },
1258 {
1259 .name = "sectors",
062a644d
VG		 1260 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1261 BLKIO_PROP_sectors),
1262 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1263 },
1264 {
1265 .name = "io_service_bytes",
062a644d
VG		 1266 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1267 BLKIO_PROP_io_service_bytes),
1268 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1269 },
1270 {
1271 .name = "io_serviced",
062a644d
VG		 1272 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1273 BLKIO_PROP_io_serviced),
1274 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1275 },
1276 {
1277 .name = "io_service_time",
062a644d
VG		 1278 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1279 BLKIO_PROP_io_service_time),
1280 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1281 },
1282 {
1283 .name = "io_wait_time",
062a644d
VG		 1284 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1285 BLKIO_PROP_io_wait_time),
1286 .read_map = blkiocg_file_read_map,
84c124da 1287 },
812d4026
DS		 1288 {
1289 .name = "io_merged",
062a644d
VG		 1290 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1291 BLKIO_PROP_io_merged),
1292 .read_map = blkiocg_file_read_map,
812d4026 1293 },
cdc1184c
DS		 1294 {
1295 .name = "io_queued",
062a644d
VG		 1296 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1297 BLKIO_PROP_io_queued),
1298 .read_map = blkiocg_file_read_map,
cdc1184c 1299 },
84c124da
DS		 1300 {
1301 .name = "reset_stats",
1302 .write_u64 = blkiocg_reset_stats,
22084190 1303 },
13f98250
VG		 1304#ifdef CONFIG_BLK_DEV_THROTTLING
1305 {
1306 .name = "throttle.read_bps_device",
1307 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1308 BLKIO_THROTL_read_bps_device),
1309 .read_seq_string = blkiocg_file_read,
1310 .write_string = blkiocg_file_write,
1311 .max_write_len = 256,
1312 },
1313
1314 {
1315 .name = "throttle.write_bps_device",
1316 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1317 BLKIO_THROTL_write_bps_device),
1318 .read_seq_string = blkiocg_file_read,
1319 .write_string = blkiocg_file_write,
1320 .max_write_len = 256,
1321 },
1322
1323 {
1324 .name = "throttle.read_iops_device",
1325 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1326 BLKIO_THROTL_read_iops_device),
1327 .read_seq_string = blkiocg_file_read,
1328 .write_string = blkiocg_file_write,
1329 .max_write_len = 256,
1330 },
1331
1332 {
1333 .name = "throttle.write_iops_device",
1334 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1335 BLKIO_THROTL_write_iops_device),
1336 .read_seq_string = blkiocg_file_read,
1337 .write_string = blkiocg_file_write,
1338 .max_write_len = 256,
1339 },
1340 {
1341 .name = "throttle.io_service_bytes",
1342 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1343 BLKIO_THROTL_io_service_bytes),
1344 .read_map = blkiocg_file_read_map,
1345 },
1346 {
1347 .name = "throttle.io_serviced",
1348 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1349 BLKIO_THROTL_io_serviced),
1350 .read_map = blkiocg_file_read_map,
1351 },
1352#endif /* CONFIG_BLK_DEV_THROTTLING */
1353
22084190 1354#ifdef CONFIG_DEBUG_BLK_CGROUP
cdc1184c
DS		 1355 {
1356 .name = "avg_queue_size",
062a644d
VG		 1357 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1358 BLKIO_PROP_avg_queue_size),
1359 .read_map = blkiocg_file_read_map,
cdc1184c 1360 },
812df48d
DS		 1361 {
1362 .name = "group_wait_time",
062a644d
VG		 1363 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1364 BLKIO_PROP_group_wait_time),
1365 .read_map = blkiocg_file_read_map,
812df48d
DS		 1366 },
1367 {
1368 .name = "idle_time",
062a644d
VG		 1369 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1370 BLKIO_PROP_idle_time),
1371 .read_map = blkiocg_file_read_map,
812df48d
DS		 1372 },
1373 {
1374 .name = "empty_time",
062a644d
VG		 1375 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1376 BLKIO_PROP_empty_time),
1377 .read_map = blkiocg_file_read_map,
812df48d 1378 },
cdc1184c 1379 {
22084190 1380 .name = "dequeue",
062a644d
VG		 1381 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1382 BLKIO_PROP_dequeue),
1383 .read_map = blkiocg_file_read_map,
cdc1184c 1384 },
22084190 1385#endif
31e4c28d
VG		 1386};
1387
1388static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1389{
1390 return cgroup_add_files(cgroup, subsys, blkio_files,
1391 ARRAY_SIZE(blkio_files));
1392}
1393
1394static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1395{
1396 struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
b1c35769
VG		 1397 unsigned long flags;
1398 struct blkio_group *blkg;
1399 void *key;
3e252066 1400 struct blkio_policy_type *blkiop;
34d0f179 1401 struct blkio_policy_node *pn, *pntmp;
b1c35769
VG		 1402
1403 rcu_read_lock();
0f3942a3
JA		 1404 do {
1405 spin_lock_irqsave(&blkcg->lock, flags);
b1c35769 1406
0f3942a3
JA		 1407 if (hlist_empty(&blkcg->blkg_list)) {
1408 spin_unlock_irqrestore(&blkcg->lock, flags);
1409 break;
1410 }
b1c35769 1411
0f3942a3
JA		 1412 blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,
1413 blkcg_node);
1414 key = rcu_dereference(blkg->key);
1415 __blkiocg_del_blkio_group(blkg);
31e4c28d 1416
0f3942a3 1417 spin_unlock_irqrestore(&blkcg->lock, flags);
b1c35769 1418
0f3942a3
JA		 1419 /*
1420 * This blkio_group is being unlinked as associated cgroup is
1421 * going away. Let all the IO controlling policies know about
61014e96 1422 * this event.
0f3942a3
JA		 1423 */
1424 spin_lock(&blkio_list_lock);
61014e96
VG		 1425 list_for_each_entry(blkiop, &blkio_list, list) {
1426 if (blkiop->plid != blkg->plid)
1427 continue;
0f3942a3 1428 blkiop->ops.blkio_unlink_group_fn(key, blkg);
61014e96 1429 }
0f3942a3
JA		 1430 spin_unlock(&blkio_list_lock);
1431 } while (1);
34d0f179 1432
34d0f179
GJ		 1433 list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
1434 blkio_policy_delete_node(pn);
1435 kfree(pn);
1436 }
0f3942a3 1437
31e4c28d 1438 free_css_id(&blkio_subsys, &blkcg->css);
b1c35769 1439 rcu_read_unlock();
67523c48
BB		 1440 if (blkcg != &blkio_root_cgroup)
1441 kfree(blkcg);
31e4c28d
VG		 1442}
1443
1444static struct cgroup_subsys_state *
1445blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1446{
0341509f
LZ		 1447 struct blkio_cgroup *blkcg;
1448 struct cgroup *parent = cgroup->parent;
31e4c28d 1449
0341509f 1450 if (!parent) {
31e4c28d
VG		 1451 blkcg = &blkio_root_cgroup;
1452 goto done;
1453 }
1454
1455 /* Currently we do not support hierarchy deeper than two level (0,1) */
0341509f 1456 if (parent != cgroup->top_cgroup)
96aa1b41 1457 return ERR_PTR(-EPERM);
31e4c28d
VG		 1458
1459 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
1460 if (!blkcg)
1461 return ERR_PTR(-ENOMEM);
1462
1463 blkcg->weight = BLKIO_WEIGHT_DEFAULT;
1464done:
1465 spin_lock_init(&blkcg->lock);
1466 INIT_HLIST_HEAD(&blkcg->blkg_list);
1467
34d0f179 1468 INIT_LIST_HEAD(&blkcg->policy_list);
31e4c28d
VG		 1469 return &blkcg->css;
1470}
1471
1472/*
1473 * We cannot support shared io contexts, as we have no mean to support
1474 * two tasks with the same ioc in two different groups without major rework
1475 * of the main cic data structures. For now we allow a task to change
1476 * its cgroup only if it's the only owner of its ioc.
1477 */
1478static int blkiocg_can_attach(struct cgroup_subsys *subsys,
1479 struct cgroup *cgroup, struct task_struct *tsk,
1480 bool threadgroup)
1481{
1482 struct io_context *ioc;
1483 int ret = 0;
1484
1485 /* task_lock() is needed to avoid races with exit_io_context() */
1486 task_lock(tsk);
1487 ioc = tsk->io_context;
1488 if (ioc && atomic_read(&ioc->nr_tasks) > 1)
1489 ret = -EINVAL;
1490 task_unlock(tsk);
1491
1492 return ret;
1493}
1494
1495static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup,
1496 struct cgroup *prev, struct task_struct *tsk,
1497 bool threadgroup)
1498{
1499 struct io_context *ioc;
1500
1501 task_lock(tsk);
1502 ioc = tsk->io_context;
1503 if (ioc)
1504 ioc->cgroup_changed = 1;
1505 task_unlock(tsk);
1506}
1507
3e252066
VG		 1508void blkio_policy_register(struct blkio_policy_type *blkiop)
1509{
1510 spin_lock(&blkio_list_lock);
1511 list_add_tail(&blkiop->list, &blkio_list);
1512 spin_unlock(&blkio_list_lock);
1513}
1514EXPORT_SYMBOL_GPL(blkio_policy_register);
1515
1516void blkio_policy_unregister(struct blkio_policy_type *blkiop)
1517{
1518 spin_lock(&blkio_list_lock);
1519 list_del_init(&blkiop->list);
1520 spin_unlock(&blkio_list_lock);
1521}
1522EXPORT_SYMBOL_GPL(blkio_policy_unregister);
67523c48
BB		 1523
1524static int __init init_cgroup_blkio(void)
1525{
1526 return cgroup_load_subsys(&blkio_subsys);
1527}
1528
1529static void __exit exit_cgroup_blkio(void)
1530{
1531 cgroup_unload_subsys(&blkio_subsys);
1532}
1533
1534module_init(init_cgroup_blkio);
1535module_exit(exit_cgroup_blkio);
1536MODULE_LICENSE("GPL");
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