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31e4c28d VG |
1 | #ifndef _BLK_CGROUP_H |
2 | #define _BLK_CGROUP_H | |
3 | /* | |
4 | * Common Block IO controller cgroup interface | |
5 | * | |
6 | * Based on ideas and code from CFQ, CFS and BFQ: | |
7 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> | |
8 | * | |
9 | * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it> | |
10 | * Paolo Valente <paolo.valente@unimore.it> | |
11 | * | |
12 | * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com> | |
13 | * Nauman Rafique <nauman@google.com> | |
14 | */ | |
15 | ||
16 | #include <linux/cgroup.h> | |
575969a0 | 17 | #include <linux/u64_stats_sync.h> |
829fdb50 | 18 | #include <linux/seq_file.h> |
a637120e | 19 | #include <linux/radix-tree.h> |
a051661c | 20 | #include <linux/blkdev.h> |
31e4c28d | 21 | |
9355aede VG |
22 | /* Max limits for throttle policy */ |
23 | #define THROTL_IOPS_MAX UINT_MAX | |
24 | ||
3381cb8d TH |
25 | /* CFQ specific, out here for blkcg->cfq_weight */ |
26 | #define CFQ_WEIGHT_MIN 10 | |
27 | #define CFQ_WEIGHT_MAX 1000 | |
28 | #define CFQ_WEIGHT_DEFAULT 500 | |
29 | ||
f48ec1d7 TH |
30 | #ifdef CONFIG_BLK_CGROUP |
31 | ||
edcb0722 TH |
32 | enum blkg_rwstat_type { |
33 | BLKG_RWSTAT_READ, | |
34 | BLKG_RWSTAT_WRITE, | |
35 | BLKG_RWSTAT_SYNC, | |
36 | BLKG_RWSTAT_ASYNC, | |
37 | ||
38 | BLKG_RWSTAT_NR, | |
39 | BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR, | |
303a3acb DS |
40 | }; |
41 | ||
a637120e TH |
42 | struct blkcg_gq; |
43 | ||
3c798398 | 44 | struct blkcg { |
36558c8a TH |
45 | struct cgroup_subsys_state css; |
46 | spinlock_t lock; | |
a637120e TH |
47 | |
48 | struct radix_tree_root blkg_tree; | |
49 | struct blkcg_gq *blkg_hint; | |
36558c8a | 50 | struct hlist_head blkg_list; |
9a9e8a26 TH |
51 | |
52 | /* for policies to test whether associated blkcg has changed */ | |
36558c8a | 53 | uint64_t id; |
3381cb8d | 54 | |
3c798398 | 55 | /* TODO: per-policy storage in blkcg */ |
36558c8a | 56 | unsigned int cfq_weight; /* belongs to cfq */ |
e71357e1 | 57 | unsigned int cfq_leaf_weight; |
31e4c28d VG |
58 | }; |
59 | ||
edcb0722 TH |
60 | struct blkg_stat { |
61 | struct u64_stats_sync syncp; | |
62 | uint64_t cnt; | |
63 | }; | |
64 | ||
65 | struct blkg_rwstat { | |
66 | struct u64_stats_sync syncp; | |
67 | uint64_t cnt[BLKG_RWSTAT_NR]; | |
68 | }; | |
69 | ||
f95a04af TH |
70 | /* |
71 | * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a | |
72 | * request_queue (q). This is used by blkcg policies which need to track | |
73 | * information per blkcg - q pair. | |
74 | * | |
75 | * There can be multiple active blkcg policies and each has its private | |
76 | * data on each blkg, the size of which is determined by | |
77 | * blkcg_policy->pd_size. blkcg core allocates and frees such areas | |
78 | * together with blkg and invokes pd_init/exit_fn() methods. | |
79 | * | |
80 | * Such private data must embed struct blkg_policy_data (pd) at the | |
81 | * beginning and pd_size can't be smaller than pd. | |
82 | */ | |
0381411e | 83 | struct blkg_policy_data { |
b276a876 | 84 | /* the blkg and policy id this per-policy data belongs to */ |
3c798398 | 85 | struct blkcg_gq *blkg; |
b276a876 | 86 | int plid; |
0381411e | 87 | |
a2b1693b | 88 | /* used during policy activation */ |
36558c8a | 89 | struct list_head alloc_node; |
0381411e TH |
90 | }; |
91 | ||
3c798398 TH |
92 | /* association between a blk cgroup and a request queue */ |
93 | struct blkcg_gq { | |
c875f4d0 | 94 | /* Pointer to the associated request_queue */ |
36558c8a TH |
95 | struct request_queue *q; |
96 | struct list_head q_node; | |
97 | struct hlist_node blkcg_node; | |
3c798398 | 98 | struct blkcg *blkcg; |
3c547865 TH |
99 | |
100 | /* all non-root blkcg_gq's are guaranteed to have access to parent */ | |
101 | struct blkcg_gq *parent; | |
102 | ||
a051661c TH |
103 | /* request allocation list for this blkcg-q pair */ |
104 | struct request_list rl; | |
3c547865 | 105 | |
1adaf3dd | 106 | /* reference count */ |
36558c8a | 107 | int refcnt; |
22084190 | 108 | |
f427d909 TH |
109 | /* is this blkg online? protected by both blkcg and q locks */ |
110 | bool online; | |
111 | ||
36558c8a | 112 | struct blkg_policy_data *pd[BLKCG_MAX_POLS]; |
1adaf3dd | 113 | |
36558c8a | 114 | struct rcu_head rcu_head; |
31e4c28d VG |
115 | }; |
116 | ||
3c798398 | 117 | typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg); |
f427d909 TH |
118 | typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg); |
119 | typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg); | |
3c798398 TH |
120 | typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg); |
121 | typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg); | |
3e252066 | 122 | |
3c798398 | 123 | struct blkcg_policy { |
36558c8a TH |
124 | int plid; |
125 | /* policy specific private data size */ | |
f95a04af | 126 | size_t pd_size; |
36558c8a TH |
127 | /* cgroup files for the policy */ |
128 | struct cftype *cftypes; | |
f9fcc2d3 TH |
129 | |
130 | /* operations */ | |
131 | blkcg_pol_init_pd_fn *pd_init_fn; | |
f427d909 TH |
132 | blkcg_pol_online_pd_fn *pd_online_fn; |
133 | blkcg_pol_offline_pd_fn *pd_offline_fn; | |
f9fcc2d3 TH |
134 | blkcg_pol_exit_pd_fn *pd_exit_fn; |
135 | blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn; | |
3e252066 VG |
136 | }; |
137 | ||
3c798398 | 138 | extern struct blkcg blkcg_root; |
36558c8a | 139 | |
3c798398 TH |
140 | struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q); |
141 | struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, | |
142 | struct request_queue *q); | |
36558c8a TH |
143 | int blkcg_init_queue(struct request_queue *q); |
144 | void blkcg_drain_queue(struct request_queue *q); | |
145 | void blkcg_exit_queue(struct request_queue *q); | |
5efd6113 | 146 | |
3e252066 | 147 | /* Blkio controller policy registration */ |
3c798398 TH |
148 | int blkcg_policy_register(struct blkcg_policy *pol); |
149 | void blkcg_policy_unregister(struct blkcg_policy *pol); | |
36558c8a | 150 | int blkcg_activate_policy(struct request_queue *q, |
3c798398 | 151 | const struct blkcg_policy *pol); |
36558c8a | 152 | void blkcg_deactivate_policy(struct request_queue *q, |
3c798398 | 153 | const struct blkcg_policy *pol); |
3e252066 | 154 | |
3c798398 | 155 | void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg, |
f95a04af TH |
156 | u64 (*prfill)(struct seq_file *, |
157 | struct blkg_policy_data *, int), | |
3c798398 | 158 | const struct blkcg_policy *pol, int data, |
ec399347 | 159 | bool show_total); |
f95a04af TH |
160 | u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v); |
161 | u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, | |
829fdb50 | 162 | const struct blkg_rwstat *rwstat); |
f95a04af TH |
163 | u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off); |
164 | u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, | |
165 | int off); | |
829fdb50 | 166 | |
16b3de66 TH |
167 | u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off); |
168 | struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd, | |
169 | int off); | |
170 | ||
829fdb50 | 171 | struct blkg_conf_ctx { |
36558c8a | 172 | struct gendisk *disk; |
3c798398 | 173 | struct blkcg_gq *blkg; |
36558c8a | 174 | u64 v; |
829fdb50 TH |
175 | }; |
176 | ||
3c798398 TH |
177 | int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, |
178 | const char *input, struct blkg_conf_ctx *ctx); | |
829fdb50 TH |
179 | void blkg_conf_finish(struct blkg_conf_ctx *ctx); |
180 | ||
181 | ||
a7c6d554 TH |
182 | static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css) |
183 | { | |
184 | return css ? container_of(css, struct blkcg, css) : NULL; | |
185 | } | |
186 | ||
b1208b56 TH |
187 | static inline struct blkcg *task_blkcg(struct task_struct *tsk) |
188 | { | |
a7c6d554 | 189 | return css_to_blkcg(task_css(tsk, blkio_subsys_id)); |
b1208b56 TH |
190 | } |
191 | ||
192 | static inline struct blkcg *bio_blkcg(struct bio *bio) | |
193 | { | |
194 | if (bio && bio->bi_css) | |
a7c6d554 | 195 | return css_to_blkcg(bio->bi_css); |
b1208b56 TH |
196 | return task_blkcg(current); |
197 | } | |
198 | ||
3c547865 TH |
199 | /** |
200 | * blkcg_parent - get the parent of a blkcg | |
201 | * @blkcg: blkcg of interest | |
202 | * | |
203 | * Return the parent blkcg of @blkcg. Can be called anytime. | |
204 | */ | |
205 | static inline struct blkcg *blkcg_parent(struct blkcg *blkcg) | |
206 | { | |
63876986 | 207 | return css_to_blkcg(css_parent(&blkcg->css)); |
3c547865 TH |
208 | } |
209 | ||
0381411e TH |
210 | /** |
211 | * blkg_to_pdata - get policy private data | |
212 | * @blkg: blkg of interest | |
213 | * @pol: policy of interest | |
214 | * | |
215 | * Return pointer to private data associated with the @blkg-@pol pair. | |
216 | */ | |
f95a04af TH |
217 | static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg, |
218 | struct blkcg_policy *pol) | |
0381411e | 219 | { |
f95a04af | 220 | return blkg ? blkg->pd[pol->plid] : NULL; |
0381411e TH |
221 | } |
222 | ||
223 | /** | |
224 | * pdata_to_blkg - get blkg associated with policy private data | |
f95a04af | 225 | * @pd: policy private data of interest |
0381411e | 226 | * |
f95a04af | 227 | * @pd is policy private data. Determine the blkg it's associated with. |
0381411e | 228 | */ |
f95a04af | 229 | static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) |
0381411e | 230 | { |
f95a04af | 231 | return pd ? pd->blkg : NULL; |
0381411e TH |
232 | } |
233 | ||
54e7ed12 TH |
234 | /** |
235 | * blkg_path - format cgroup path of blkg | |
236 | * @blkg: blkg of interest | |
237 | * @buf: target buffer | |
238 | * @buflen: target buffer length | |
239 | * | |
240 | * Format the path of the cgroup of @blkg into @buf. | |
241 | */ | |
3c798398 | 242 | static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen) |
afc24d49 | 243 | { |
54e7ed12 TH |
244 | int ret; |
245 | ||
54e7ed12 | 246 | ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen); |
54e7ed12 TH |
247 | if (ret) |
248 | strncpy(buf, "<unavailable>", buflen); | |
249 | return ret; | |
afc24d49 VG |
250 | } |
251 | ||
1adaf3dd TH |
252 | /** |
253 | * blkg_get - get a blkg reference | |
254 | * @blkg: blkg to get | |
255 | * | |
256 | * The caller should be holding queue_lock and an existing reference. | |
257 | */ | |
3c798398 | 258 | static inline void blkg_get(struct blkcg_gq *blkg) |
1adaf3dd TH |
259 | { |
260 | lockdep_assert_held(blkg->q->queue_lock); | |
261 | WARN_ON_ONCE(!blkg->refcnt); | |
262 | blkg->refcnt++; | |
263 | } | |
264 | ||
2a4fd070 | 265 | void __blkg_release_rcu(struct rcu_head *rcu); |
1adaf3dd TH |
266 | |
267 | /** | |
268 | * blkg_put - put a blkg reference | |
269 | * @blkg: blkg to put | |
270 | * | |
271 | * The caller should be holding queue_lock. | |
272 | */ | |
3c798398 | 273 | static inline void blkg_put(struct blkcg_gq *blkg) |
1adaf3dd TH |
274 | { |
275 | lockdep_assert_held(blkg->q->queue_lock); | |
276 | WARN_ON_ONCE(blkg->refcnt <= 0); | |
277 | if (!--blkg->refcnt) | |
2a4fd070 | 278 | call_rcu(&blkg->rcu_head, __blkg_release_rcu); |
1adaf3dd TH |
279 | } |
280 | ||
dd4a4ffc TH |
281 | struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q, |
282 | bool update_hint); | |
283 | ||
284 | /** | |
285 | * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants | |
286 | * @d_blkg: loop cursor pointing to the current descendant | |
492eb21b | 287 | * @pos_css: used for iteration |
dd4a4ffc TH |
288 | * @p_blkg: target blkg to walk descendants of |
289 | * | |
290 | * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU | |
291 | * read locked. If called under either blkcg or queue lock, the iteration | |
292 | * is guaranteed to include all and only online blkgs. The caller may | |
492eb21b | 293 | * update @pos_css by calling css_rightmost_descendant() to skip subtree. |
bd8815a6 | 294 | * @p_blkg is included in the iteration and the first node to be visited. |
dd4a4ffc | 295 | */ |
492eb21b TH |
296 | #define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \ |
297 | css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \ | |
298 | if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \ | |
dd4a4ffc TH |
299 | (p_blkg)->q, false))) |
300 | ||
aa539cb3 TH |
301 | /** |
302 | * blkg_for_each_descendant_post - post-order walk of a blkg's descendants | |
303 | * @d_blkg: loop cursor pointing to the current descendant | |
492eb21b | 304 | * @pos_css: used for iteration |
aa539cb3 TH |
305 | * @p_blkg: target blkg to walk descendants of |
306 | * | |
307 | * Similar to blkg_for_each_descendant_pre() but performs post-order | |
bd8815a6 TH |
308 | * traversal instead. Synchronization rules are the same. @p_blkg is |
309 | * included in the iteration and the last node to be visited. | |
aa539cb3 | 310 | */ |
492eb21b TH |
311 | #define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \ |
312 | css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \ | |
313 | if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \ | |
aa539cb3 TH |
314 | (p_blkg)->q, false))) |
315 | ||
a051661c TH |
316 | /** |
317 | * blk_get_rl - get request_list to use | |
318 | * @q: request_queue of interest | |
319 | * @bio: bio which will be attached to the allocated request (may be %NULL) | |
320 | * | |
321 | * The caller wants to allocate a request from @q to use for @bio. Find | |
322 | * the request_list to use and obtain a reference on it. Should be called | |
323 | * under queue_lock. This function is guaranteed to return non-%NULL | |
324 | * request_list. | |
325 | */ | |
326 | static inline struct request_list *blk_get_rl(struct request_queue *q, | |
327 | struct bio *bio) | |
328 | { | |
329 | struct blkcg *blkcg; | |
330 | struct blkcg_gq *blkg; | |
331 | ||
332 | rcu_read_lock(); | |
333 | ||
334 | blkcg = bio_blkcg(bio); | |
335 | ||
336 | /* bypass blkg lookup and use @q->root_rl directly for root */ | |
337 | if (blkcg == &blkcg_root) | |
338 | goto root_rl; | |
339 | ||
340 | /* | |
341 | * Try to use blkg->rl. blkg lookup may fail under memory pressure | |
342 | * or if either the blkcg or queue is going away. Fall back to | |
343 | * root_rl in such cases. | |
344 | */ | |
345 | blkg = blkg_lookup_create(blkcg, q); | |
346 | if (unlikely(IS_ERR(blkg))) | |
347 | goto root_rl; | |
348 | ||
349 | blkg_get(blkg); | |
350 | rcu_read_unlock(); | |
351 | return &blkg->rl; | |
352 | root_rl: | |
353 | rcu_read_unlock(); | |
354 | return &q->root_rl; | |
355 | } | |
356 | ||
357 | /** | |
358 | * blk_put_rl - put request_list | |
359 | * @rl: request_list to put | |
360 | * | |
361 | * Put the reference acquired by blk_get_rl(). Should be called under | |
362 | * queue_lock. | |
363 | */ | |
364 | static inline void blk_put_rl(struct request_list *rl) | |
365 | { | |
366 | /* root_rl may not have blkg set */ | |
367 | if (rl->blkg && rl->blkg->blkcg != &blkcg_root) | |
368 | blkg_put(rl->blkg); | |
369 | } | |
370 | ||
371 | /** | |
372 | * blk_rq_set_rl - associate a request with a request_list | |
373 | * @rq: request of interest | |
374 | * @rl: target request_list | |
375 | * | |
376 | * Associate @rq with @rl so that accounting and freeing can know the | |
377 | * request_list @rq came from. | |
378 | */ | |
379 | static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) | |
380 | { | |
381 | rq->rl = rl; | |
382 | } | |
383 | ||
384 | /** | |
385 | * blk_rq_rl - return the request_list a request came from | |
386 | * @rq: request of interest | |
387 | * | |
388 | * Return the request_list @rq is allocated from. | |
389 | */ | |
390 | static inline struct request_list *blk_rq_rl(struct request *rq) | |
391 | { | |
392 | return rq->rl; | |
393 | } | |
394 | ||
395 | struct request_list *__blk_queue_next_rl(struct request_list *rl, | |
396 | struct request_queue *q); | |
397 | /** | |
398 | * blk_queue_for_each_rl - iterate through all request_lists of a request_queue | |
399 | * | |
400 | * Should be used under queue_lock. | |
401 | */ | |
402 | #define blk_queue_for_each_rl(rl, q) \ | |
403 | for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q))) | |
404 | ||
90d3839b PZ |
405 | static inline void blkg_stat_init(struct blkg_stat *stat) |
406 | { | |
407 | u64_stats_init(&stat->syncp); | |
408 | } | |
409 | ||
edcb0722 TH |
410 | /** |
411 | * blkg_stat_add - add a value to a blkg_stat | |
412 | * @stat: target blkg_stat | |
413 | * @val: value to add | |
414 | * | |
415 | * Add @val to @stat. The caller is responsible for synchronizing calls to | |
416 | * this function. | |
417 | */ | |
418 | static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val) | |
419 | { | |
420 | u64_stats_update_begin(&stat->syncp); | |
421 | stat->cnt += val; | |
422 | u64_stats_update_end(&stat->syncp); | |
423 | } | |
424 | ||
425 | /** | |
426 | * blkg_stat_read - read the current value of a blkg_stat | |
427 | * @stat: blkg_stat to read | |
428 | * | |
429 | * Read the current value of @stat. This function can be called without | |
430 | * synchroniztion and takes care of u64 atomicity. | |
431 | */ | |
432 | static inline uint64_t blkg_stat_read(struct blkg_stat *stat) | |
433 | { | |
434 | unsigned int start; | |
435 | uint64_t v; | |
436 | ||
437 | do { | |
438 | start = u64_stats_fetch_begin(&stat->syncp); | |
439 | v = stat->cnt; | |
440 | } while (u64_stats_fetch_retry(&stat->syncp, start)); | |
441 | ||
442 | return v; | |
443 | } | |
444 | ||
445 | /** | |
446 | * blkg_stat_reset - reset a blkg_stat | |
447 | * @stat: blkg_stat to reset | |
448 | */ | |
449 | static inline void blkg_stat_reset(struct blkg_stat *stat) | |
450 | { | |
451 | stat->cnt = 0; | |
452 | } | |
453 | ||
16b3de66 TH |
454 | /** |
455 | * blkg_stat_merge - merge a blkg_stat into another | |
456 | * @to: the destination blkg_stat | |
457 | * @from: the source | |
458 | * | |
459 | * Add @from's count to @to. | |
460 | */ | |
461 | static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from) | |
462 | { | |
463 | blkg_stat_add(to, blkg_stat_read(from)); | |
464 | } | |
465 | ||
90d3839b PZ |
466 | static inline void blkg_rwstat_init(struct blkg_rwstat *rwstat) |
467 | { | |
468 | u64_stats_init(&rwstat->syncp); | |
469 | } | |
470 | ||
edcb0722 TH |
471 | /** |
472 | * blkg_rwstat_add - add a value to a blkg_rwstat | |
473 | * @rwstat: target blkg_rwstat | |
474 | * @rw: mask of REQ_{WRITE|SYNC} | |
475 | * @val: value to add | |
476 | * | |
477 | * Add @val to @rwstat. The counters are chosen according to @rw. The | |
478 | * caller is responsible for synchronizing calls to this function. | |
479 | */ | |
480 | static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat, | |
481 | int rw, uint64_t val) | |
482 | { | |
483 | u64_stats_update_begin(&rwstat->syncp); | |
484 | ||
485 | if (rw & REQ_WRITE) | |
486 | rwstat->cnt[BLKG_RWSTAT_WRITE] += val; | |
487 | else | |
488 | rwstat->cnt[BLKG_RWSTAT_READ] += val; | |
489 | if (rw & REQ_SYNC) | |
490 | rwstat->cnt[BLKG_RWSTAT_SYNC] += val; | |
491 | else | |
492 | rwstat->cnt[BLKG_RWSTAT_ASYNC] += val; | |
493 | ||
494 | u64_stats_update_end(&rwstat->syncp); | |
495 | } | |
496 | ||
497 | /** | |
498 | * blkg_rwstat_read - read the current values of a blkg_rwstat | |
499 | * @rwstat: blkg_rwstat to read | |
500 | * | |
501 | * Read the current snapshot of @rwstat and return it as the return value. | |
502 | * This function can be called without synchronization and takes care of | |
503 | * u64 atomicity. | |
504 | */ | |
c94bed89 | 505 | static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat) |
edcb0722 TH |
506 | { |
507 | unsigned int start; | |
508 | struct blkg_rwstat tmp; | |
509 | ||
510 | do { | |
511 | start = u64_stats_fetch_begin(&rwstat->syncp); | |
512 | tmp = *rwstat; | |
513 | } while (u64_stats_fetch_retry(&rwstat->syncp, start)); | |
514 | ||
515 | return tmp; | |
516 | } | |
517 | ||
518 | /** | |
4d5e80a7 | 519 | * blkg_rwstat_total - read the total count of a blkg_rwstat |
edcb0722 TH |
520 | * @rwstat: blkg_rwstat to read |
521 | * | |
522 | * Return the total count of @rwstat regardless of the IO direction. This | |
523 | * function can be called without synchronization and takes care of u64 | |
524 | * atomicity. | |
525 | */ | |
4d5e80a7 | 526 | static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat) |
edcb0722 TH |
527 | { |
528 | struct blkg_rwstat tmp = blkg_rwstat_read(rwstat); | |
529 | ||
530 | return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE]; | |
531 | } | |
532 | ||
533 | /** | |
534 | * blkg_rwstat_reset - reset a blkg_rwstat | |
535 | * @rwstat: blkg_rwstat to reset | |
536 | */ | |
537 | static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat) | |
538 | { | |
539 | memset(rwstat->cnt, 0, sizeof(rwstat->cnt)); | |
540 | } | |
541 | ||
16b3de66 TH |
542 | /** |
543 | * blkg_rwstat_merge - merge a blkg_rwstat into another | |
544 | * @to: the destination blkg_rwstat | |
545 | * @from: the source | |
546 | * | |
547 | * Add @from's counts to @to. | |
548 | */ | |
549 | static inline void blkg_rwstat_merge(struct blkg_rwstat *to, | |
550 | struct blkg_rwstat *from) | |
551 | { | |
552 | struct blkg_rwstat v = blkg_rwstat_read(from); | |
553 | int i; | |
554 | ||
555 | u64_stats_update_begin(&to->syncp); | |
556 | for (i = 0; i < BLKG_RWSTAT_NR; i++) | |
557 | to->cnt[i] += v.cnt[i]; | |
558 | u64_stats_update_end(&to->syncp); | |
559 | } | |
560 | ||
36558c8a TH |
561 | #else /* CONFIG_BLK_CGROUP */ |
562 | ||
563 | struct cgroup; | |
b1208b56 | 564 | struct blkcg; |
2f5ea477 | 565 | |
f95a04af TH |
566 | struct blkg_policy_data { |
567 | }; | |
568 | ||
3c798398 | 569 | struct blkcg_gq { |
2f5ea477 JA |
570 | }; |
571 | ||
3c798398 | 572 | struct blkcg_policy { |
3e252066 VG |
573 | }; |
574 | ||
3c798398 | 575 | static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; } |
5efd6113 TH |
576 | static inline int blkcg_init_queue(struct request_queue *q) { return 0; } |
577 | static inline void blkcg_drain_queue(struct request_queue *q) { } | |
578 | static inline void blkcg_exit_queue(struct request_queue *q) { } | |
3c798398 TH |
579 | static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; } |
580 | static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { } | |
a2b1693b | 581 | static inline int blkcg_activate_policy(struct request_queue *q, |
3c798398 | 582 | const struct blkcg_policy *pol) { return 0; } |
a2b1693b | 583 | static inline void blkcg_deactivate_policy(struct request_queue *q, |
3c798398 TH |
584 | const struct blkcg_policy *pol) { } |
585 | ||
b1208b56 | 586 | static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; } |
a051661c | 587 | |
f95a04af TH |
588 | static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg, |
589 | struct blkcg_policy *pol) { return NULL; } | |
590 | static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; } | |
3c798398 TH |
591 | static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; } |
592 | static inline void blkg_get(struct blkcg_gq *blkg) { } | |
593 | static inline void blkg_put(struct blkcg_gq *blkg) { } | |
afc24d49 | 594 | |
a051661c TH |
595 | static inline struct request_list *blk_get_rl(struct request_queue *q, |
596 | struct bio *bio) { return &q->root_rl; } | |
597 | static inline void blk_put_rl(struct request_list *rl) { } | |
598 | static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { } | |
599 | static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; } | |
600 | ||
601 | #define blk_queue_for_each_rl(rl, q) \ | |
602 | for ((rl) = &(q)->root_rl; (rl); (rl) = NULL) | |
603 | ||
36558c8a TH |
604 | #endif /* CONFIG_BLK_CGROUP */ |
605 | #endif /* _BLK_CGROUP_H */ |