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Vivek Goyal31e4c282009-12-03 12:59:42 -05001#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>
Vivek Goyal575969a2011-05-19 15:38:29 -040017#include <linux/u64_stats_sync.h>
Tejun Heo829fdb52012-04-01 14:38:43 -070018#include <linux/seq_file.h>
Tejun Heoa6371202012-04-19 16:29:24 -070019#include <linux/radix-tree.h>
Tejun Heoa0516612012-06-26 15:05:44 -070020#include <linux/blkdev.h>
Vivek Goyal31e4c282009-12-03 12:59:42 -050021
Vivek Goyal9355aed2010-10-01 21:16:41 +020022/* Max limits for throttle policy */
23#define THROTL_IOPS_MAX UINT_MAX
24
Tejun Heo3381cb82012-04-01 14:38:44 -070025/* 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
Tejun Heof48ec1d2012-04-13 13:11:25 -070030#ifdef CONFIG_BLK_CGROUP
31
Tejun Heoedcb0722012-04-01 14:38:42 -070032enum 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,
Divyesh Shah303a3ac2010-04-01 15:01:24 -070040};
41
Tejun Heoa6371202012-04-19 16:29:24 -070042struct blkcg_gq;
43
Tejun Heo3c798392012-04-16 13:57:25 -070044struct blkcg {
Tejun Heo36558c82012-04-16 13:57:24 -070045 struct cgroup_subsys_state css;
46 spinlock_t lock;
Tejun Heoa6371202012-04-19 16:29:24 -070047
48 struct radix_tree_root blkg_tree;
49 struct blkcg_gq *blkg_hint;
Tejun Heo36558c82012-04-16 13:57:24 -070050 struct hlist_head blkg_list;
Tejun Heo9a9e8a22012-03-19 15:10:56 -070051
52 /* for policies to test whether associated blkcg has changed */
Tejun Heo36558c82012-04-16 13:57:24 -070053 uint64_t id;
Tejun Heo3381cb82012-04-01 14:38:44 -070054
Tejun Heo3c798392012-04-16 13:57:25 -070055 /* TODO: per-policy storage in blkcg */
Tejun Heo36558c82012-04-16 13:57:24 -070056 unsigned int cfq_weight; /* belongs to cfq */
Tejun Heoe71357e2013-01-09 08:05:10 -080057 unsigned int cfq_leaf_weight;
Vivek Goyal31e4c282009-12-03 12:59:42 -050058};
59
Tejun Heoedcb0722012-04-01 14:38:42 -070060struct blkg_stat {
61 struct u64_stats_sync syncp;
62 uint64_t cnt;
63};
64
65struct blkg_rwstat {
66 struct u64_stats_sync syncp;
67 uint64_t cnt[BLKG_RWSTAT_NR];
68};
69
Tejun Heof95a04a2012-04-16 13:57:26 -070070/*
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 */
Tejun Heo03814112012-03-05 13:15:14 -080083struct blkg_policy_data {
Tejun Heob276a872013-01-09 08:05:12 -080084 /* the blkg and policy id this per-policy data belongs to */
Tejun Heo3c798392012-04-16 13:57:25 -070085 struct blkcg_gq *blkg;
Tejun Heob276a872013-01-09 08:05:12 -080086 int plid;
Tejun Heo03814112012-03-05 13:15:14 -080087
Tejun Heoa2b16932012-04-13 13:11:33 -070088 /* used during policy activation */
Tejun Heo36558c82012-04-16 13:57:24 -070089 struct list_head alloc_node;
Tejun Heo03814112012-03-05 13:15:14 -080090};
91
Tejun Heo3c798392012-04-16 13:57:25 -070092/* association between a blk cgroup and a request queue */
93struct blkcg_gq {
Tejun Heoc875f4d2012-03-05 13:15:22 -080094 /* Pointer to the associated request_queue */
Tejun Heo36558c82012-04-16 13:57:24 -070095 struct request_queue *q;
96 struct list_head q_node;
97 struct hlist_node blkcg_node;
Tejun Heo3c798392012-04-16 13:57:25 -070098 struct blkcg *blkcg;
Tejun Heo3c547862013-01-09 08:05:10 -080099
100 /* all non-root blkcg_gq's are guaranteed to have access to parent */
101 struct blkcg_gq *parent;
102
Tejun Heoa0516612012-06-26 15:05:44 -0700103 /* request allocation list for this blkcg-q pair */
104 struct request_list rl;
Tejun Heo3c547862013-01-09 08:05:10 -0800105
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800106 /* reference count */
Tejun Heo36558c82012-04-16 13:57:24 -0700107 int refcnt;
Vivek Goyal22084192009-12-03 12:59:49 -0500108
Tejun Heof427d902013-01-09 08:05:12 -0800109 /* is this blkg online? protected by both blkcg and q locks */
110 bool online;
111
Tejun Heo36558c82012-04-16 13:57:24 -0700112 struct blkg_policy_data *pd[BLKCG_MAX_POLS];
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800113
Tejun Heo36558c82012-04-16 13:57:24 -0700114 struct rcu_head rcu_head;
Vivek Goyal31e4c282009-12-03 12:59:42 -0500115};
116
Tejun Heo3c798392012-04-16 13:57:25 -0700117typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
Tejun Heof427d902013-01-09 08:05:12 -0800118typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg);
119typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg);
Tejun Heo3c798392012-04-16 13:57:25 -0700120typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
121typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
Vivek Goyal3e252062009-12-04 10:36:42 -0500122
Tejun Heo3c798392012-04-16 13:57:25 -0700123struct blkcg_policy {
Tejun Heo36558c82012-04-16 13:57:24 -0700124 int plid;
125 /* policy specific private data size */
Tejun Heof95a04a2012-04-16 13:57:26 -0700126 size_t pd_size;
Tejun Heo36558c82012-04-16 13:57:24 -0700127 /* cgroup files for the policy */
128 struct cftype *cftypes;
Tejun Heof9fcc2d2012-04-16 13:57:27 -0700129
130 /* operations */
131 blkcg_pol_init_pd_fn *pd_init_fn;
Tejun Heof427d902013-01-09 08:05:12 -0800132 blkcg_pol_online_pd_fn *pd_online_fn;
133 blkcg_pol_offline_pd_fn *pd_offline_fn;
Tejun Heof9fcc2d2012-04-16 13:57:27 -0700134 blkcg_pol_exit_pd_fn *pd_exit_fn;
135 blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
Vivek Goyal3e252062009-12-04 10:36:42 -0500136};
137
Tejun Heo3c798392012-04-16 13:57:25 -0700138extern struct blkcg blkcg_root;
Tejun Heo36558c82012-04-16 13:57:24 -0700139
Tejun Heo3c798392012-04-16 13:57:25 -0700140struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
141struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
142 struct request_queue *q);
Tejun Heo36558c82012-04-16 13:57:24 -0700143int blkcg_init_queue(struct request_queue *q);
144void blkcg_drain_queue(struct request_queue *q);
145void blkcg_exit_queue(struct request_queue *q);
Tejun Heo5efd6112012-03-05 13:15:12 -0800146
Vivek Goyal3e252062009-12-04 10:36:42 -0500147/* Blkio controller policy registration */
Fabian Fredericka2d445d2014-06-10 20:18:36 +0200148int __init blkcg_policy_register(struct blkcg_policy *pol);
Tejun Heo3c798392012-04-16 13:57:25 -0700149void blkcg_policy_unregister(struct blkcg_policy *pol);
Tejun Heo36558c82012-04-16 13:57:24 -0700150int blkcg_activate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700151 const struct blkcg_policy *pol);
Tejun Heo36558c82012-04-16 13:57:24 -0700152void blkcg_deactivate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700153 const struct blkcg_policy *pol);
Vivek Goyal3e252062009-12-04 10:36:42 -0500154
Tejun Heo3c798392012-04-16 13:57:25 -0700155void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
Tejun Heof95a04a2012-04-16 13:57:26 -0700156 u64 (*prfill)(struct seq_file *,
157 struct blkg_policy_data *, int),
Tejun Heo3c798392012-04-16 13:57:25 -0700158 const struct blkcg_policy *pol, int data,
Tejun Heoec399342012-04-13 13:11:27 -0700159 bool show_total);
Tejun Heof95a04a2012-04-16 13:57:26 -0700160u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
161u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
Tejun Heo829fdb52012-04-01 14:38:43 -0700162 const struct blkg_rwstat *rwstat);
Tejun Heof95a04a2012-04-16 13:57:26 -0700163u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
164u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
165 int off);
Tejun Heo829fdb52012-04-01 14:38:43 -0700166
Tejun Heo16b3de62013-01-09 08:05:12 -0800167u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off);
168struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
169 int off);
170
Tejun Heo829fdb52012-04-01 14:38:43 -0700171struct blkg_conf_ctx {
Tejun Heo36558c82012-04-16 13:57:24 -0700172 struct gendisk *disk;
Tejun Heo3c798392012-04-16 13:57:25 -0700173 struct blkcg_gq *blkg;
Tejun Heo36558c82012-04-16 13:57:24 -0700174 u64 v;
Tejun Heo829fdb52012-04-01 14:38:43 -0700175};
176
Tejun Heo3c798392012-04-16 13:57:25 -0700177int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
178 const char *input, struct blkg_conf_ctx *ctx);
Tejun Heo829fdb52012-04-01 14:38:43 -0700179void blkg_conf_finish(struct blkg_conf_ctx *ctx);
180
181
Tejun Heoa7c6d552013-08-08 20:11:23 -0400182static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
183{
184 return css ? container_of(css, struct blkcg, css) : NULL;
185}
186
Tejun Heob1208b52012-06-04 20:40:57 -0700187static inline struct blkcg *task_blkcg(struct task_struct *tsk)
188{
Tejun Heo073219e2014-02-08 10:36:58 -0500189 return css_to_blkcg(task_css(tsk, blkio_cgrp_id));
Tejun Heob1208b52012-06-04 20:40:57 -0700190}
191
192static inline struct blkcg *bio_blkcg(struct bio *bio)
193{
194 if (bio && bio->bi_css)
Tejun Heoa7c6d552013-08-08 20:11:23 -0400195 return css_to_blkcg(bio->bi_css);
Tejun Heob1208b52012-06-04 20:40:57 -0700196 return task_blkcg(current);
197}
198
Tejun Heo03814112012-03-05 13:15:14 -0800199/**
Tejun Heo3c547862013-01-09 08:05:10 -0800200 * 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 */
205static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
206{
Tejun Heo5c9d5352014-05-16 13:22:48 -0400207 return css_to_blkcg(blkcg->css.parent);
Tejun Heo3c547862013-01-09 08:05:10 -0800208}
209
210/**
Tejun Heo03814112012-03-05 13:15:14 -0800211 * 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 */
Tejun Heof95a04a2012-04-16 13:57:26 -0700217static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
218 struct blkcg_policy *pol)
Tejun Heo03814112012-03-05 13:15:14 -0800219{
Tejun Heof95a04a2012-04-16 13:57:26 -0700220 return blkg ? blkg->pd[pol->plid] : NULL;
Tejun Heo03814112012-03-05 13:15:14 -0800221}
222
223/**
224 * pdata_to_blkg - get blkg associated with policy private data
Tejun Heof95a04a2012-04-16 13:57:26 -0700225 * @pd: policy private data of interest
Tejun Heo03814112012-03-05 13:15:14 -0800226 *
Tejun Heof95a04a2012-04-16 13:57:26 -0700227 * @pd is policy private data. Determine the blkg it's associated with.
Tejun Heo03814112012-03-05 13:15:14 -0800228 */
Tejun Heof95a04a2012-04-16 13:57:26 -0700229static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
Tejun Heo03814112012-03-05 13:15:14 -0800230{
Tejun Heof95a04a2012-04-16 13:57:26 -0700231 return pd ? pd->blkg : NULL;
Tejun Heo03814112012-03-05 13:15:14 -0800232}
233
Tejun Heo54e7ed12012-04-16 13:57:23 -0700234/**
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 */
Tejun Heo3c798392012-04-16 13:57:25 -0700242static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
Vivek Goyalafc24d42010-04-26 19:27:56 +0200243{
Tejun Heoe61734c2014-02-12 09:29:50 -0500244 char *p;
Tejun Heo54e7ed12012-04-16 13:57:23 -0700245
Tejun Heoe61734c2014-02-12 09:29:50 -0500246 p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
247 if (!p) {
Tejun Heo54e7ed12012-04-16 13:57:23 -0700248 strncpy(buf, "<unavailable>", buflen);
Tejun Heoe61734c2014-02-12 09:29:50 -0500249 return -ENAMETOOLONG;
250 }
251
252 memmove(buf, p, buf + buflen - p);
253 return 0;
Vivek Goyalafc24d42010-04-26 19:27:56 +0200254}
255
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800256/**
257 * blkg_get - get a blkg reference
258 * @blkg: blkg to get
259 *
260 * The caller should be holding queue_lock and an existing reference.
261 */
Tejun Heo3c798392012-04-16 13:57:25 -0700262static inline void blkg_get(struct blkcg_gq *blkg)
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800263{
264 lockdep_assert_held(blkg->q->queue_lock);
265 WARN_ON_ONCE(!blkg->refcnt);
266 blkg->refcnt++;
267}
268
Tejun Heo2a4fd072013-05-14 13:52:31 -0700269void __blkg_release_rcu(struct rcu_head *rcu);
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800270
271/**
272 * blkg_put - put a blkg reference
273 * @blkg: blkg to put
274 *
275 * The caller should be holding queue_lock.
276 */
Tejun Heo3c798392012-04-16 13:57:25 -0700277static inline void blkg_put(struct blkcg_gq *blkg)
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800278{
279 lockdep_assert_held(blkg->q->queue_lock);
280 WARN_ON_ONCE(blkg->refcnt <= 0);
281 if (!--blkg->refcnt)
Tejun Heo2a4fd072013-05-14 13:52:31 -0700282 call_rcu(&blkg->rcu_head, __blkg_release_rcu);
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800283}
284
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700285struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q,
286 bool update_hint);
287
288/**
289 * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
290 * @d_blkg: loop cursor pointing to the current descendant
Tejun Heo492eb212013-08-08 20:11:25 -0400291 * @pos_css: used for iteration
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700292 * @p_blkg: target blkg to walk descendants of
293 *
294 * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
295 * read locked. If called under either blkcg or queue lock, the iteration
296 * is guaranteed to include all and only online blkgs. The caller may
Tejun Heo492eb212013-08-08 20:11:25 -0400297 * update @pos_css by calling css_rightmost_descendant() to skip subtree.
Tejun Heobd8815a2013-08-08 20:11:27 -0400298 * @p_blkg is included in the iteration and the first node to be visited.
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700299 */
Tejun Heo492eb212013-08-08 20:11:25 -0400300#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \
301 css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \
302 if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700303 (p_blkg)->q, false)))
304
Tejun Heoedcb0722012-04-01 14:38:42 -0700305/**
Tejun Heoaa539cb2013-05-14 13:52:31 -0700306 * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
307 * @d_blkg: loop cursor pointing to the current descendant
Tejun Heo492eb212013-08-08 20:11:25 -0400308 * @pos_css: used for iteration
Tejun Heoaa539cb2013-05-14 13:52:31 -0700309 * @p_blkg: target blkg to walk descendants of
310 *
311 * Similar to blkg_for_each_descendant_pre() but performs post-order
Tejun Heobd8815a2013-08-08 20:11:27 -0400312 * traversal instead. Synchronization rules are the same. @p_blkg is
313 * included in the iteration and the last node to be visited.
Tejun Heoaa539cb2013-05-14 13:52:31 -0700314 */
Tejun Heo492eb212013-08-08 20:11:25 -0400315#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \
316 css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \
317 if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
Tejun Heoaa539cb2013-05-14 13:52:31 -0700318 (p_blkg)->q, false)))
319
320/**
Tejun Heoa0516612012-06-26 15:05:44 -0700321 * blk_get_rl - get request_list to use
322 * @q: request_queue of interest
323 * @bio: bio which will be attached to the allocated request (may be %NULL)
324 *
325 * The caller wants to allocate a request from @q to use for @bio. Find
326 * the request_list to use and obtain a reference on it. Should be called
327 * under queue_lock. This function is guaranteed to return non-%NULL
328 * request_list.
329 */
330static inline struct request_list *blk_get_rl(struct request_queue *q,
331 struct bio *bio)
332{
333 struct blkcg *blkcg;
334 struct blkcg_gq *blkg;
335
336 rcu_read_lock();
337
338 blkcg = bio_blkcg(bio);
339
340 /* bypass blkg lookup and use @q->root_rl directly for root */
341 if (blkcg == &blkcg_root)
342 goto root_rl;
343
344 /*
345 * Try to use blkg->rl. blkg lookup may fail under memory pressure
346 * or if either the blkcg or queue is going away. Fall back to
347 * root_rl in such cases.
348 */
349 blkg = blkg_lookup_create(blkcg, q);
350 if (unlikely(IS_ERR(blkg)))
351 goto root_rl;
352
353 blkg_get(blkg);
354 rcu_read_unlock();
355 return &blkg->rl;
356root_rl:
357 rcu_read_unlock();
358 return &q->root_rl;
359}
360
361/**
362 * blk_put_rl - put request_list
363 * @rl: request_list to put
364 *
365 * Put the reference acquired by blk_get_rl(). Should be called under
366 * queue_lock.
367 */
368static inline void blk_put_rl(struct request_list *rl)
369{
370 /* root_rl may not have blkg set */
371 if (rl->blkg && rl->blkg->blkcg != &blkcg_root)
372 blkg_put(rl->blkg);
373}
374
375/**
376 * blk_rq_set_rl - associate a request with a request_list
377 * @rq: request of interest
378 * @rl: target request_list
379 *
380 * Associate @rq with @rl so that accounting and freeing can know the
381 * request_list @rq came from.
382 */
383static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
384{
385 rq->rl = rl;
386}
387
388/**
389 * blk_rq_rl - return the request_list a request came from
390 * @rq: request of interest
391 *
392 * Return the request_list @rq is allocated from.
393 */
394static inline struct request_list *blk_rq_rl(struct request *rq)
395{
396 return rq->rl;
397}
398
399struct request_list *__blk_queue_next_rl(struct request_list *rl,
400 struct request_queue *q);
401/**
402 * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
403 *
404 * Should be used under queue_lock.
405 */
406#define blk_queue_for_each_rl(rl, q) \
407 for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
408
Peter Zijlstra90d38392013-11-12 19:42:14 -0800409static inline void blkg_stat_init(struct blkg_stat *stat)
410{
411 u64_stats_init(&stat->syncp);
412}
413
Tejun Heoa0516612012-06-26 15:05:44 -0700414/**
Tejun Heoedcb0722012-04-01 14:38:42 -0700415 * blkg_stat_add - add a value to a blkg_stat
416 * @stat: target blkg_stat
417 * @val: value to add
418 *
419 * Add @val to @stat. The caller is responsible for synchronizing calls to
420 * this function.
421 */
422static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
423{
424 u64_stats_update_begin(&stat->syncp);
425 stat->cnt += val;
426 u64_stats_update_end(&stat->syncp);
427}
428
429/**
430 * blkg_stat_read - read the current value of a blkg_stat
431 * @stat: blkg_stat to read
432 *
433 * Read the current value of @stat. This function can be called without
434 * synchroniztion and takes care of u64 atomicity.
435 */
436static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
437{
438 unsigned int start;
439 uint64_t v;
440
441 do {
Eric W. Biederman57a77442014-03-13 21:26:42 -0700442 start = u64_stats_fetch_begin_irq(&stat->syncp);
Tejun Heoedcb0722012-04-01 14:38:42 -0700443 v = stat->cnt;
Eric W. Biederman57a77442014-03-13 21:26:42 -0700444 } while (u64_stats_fetch_retry_irq(&stat->syncp, start));
Tejun Heoedcb0722012-04-01 14:38:42 -0700445
446 return v;
447}
448
449/**
450 * blkg_stat_reset - reset a blkg_stat
451 * @stat: blkg_stat to reset
452 */
453static inline void blkg_stat_reset(struct blkg_stat *stat)
454{
455 stat->cnt = 0;
456}
457
458/**
Tejun Heo16b3de62013-01-09 08:05:12 -0800459 * blkg_stat_merge - merge a blkg_stat into another
460 * @to: the destination blkg_stat
461 * @from: the source
462 *
463 * Add @from's count to @to.
464 */
465static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from)
466{
467 blkg_stat_add(to, blkg_stat_read(from));
468}
469
Peter Zijlstra90d38392013-11-12 19:42:14 -0800470static inline void blkg_rwstat_init(struct blkg_rwstat *rwstat)
471{
472 u64_stats_init(&rwstat->syncp);
473}
474
Tejun Heo16b3de62013-01-09 08:05:12 -0800475/**
Tejun Heoedcb0722012-04-01 14:38:42 -0700476 * blkg_rwstat_add - add a value to a blkg_rwstat
477 * @rwstat: target blkg_rwstat
478 * @rw: mask of REQ_{WRITE|SYNC}
479 * @val: value to add
480 *
481 * Add @val to @rwstat. The counters are chosen according to @rw. The
482 * caller is responsible for synchronizing calls to this function.
483 */
484static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
485 int rw, uint64_t val)
486{
487 u64_stats_update_begin(&rwstat->syncp);
488
489 if (rw & REQ_WRITE)
490 rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
491 else
492 rwstat->cnt[BLKG_RWSTAT_READ] += val;
493 if (rw & REQ_SYNC)
494 rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
495 else
496 rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
497
498 u64_stats_update_end(&rwstat->syncp);
499}
500
501/**
502 * blkg_rwstat_read - read the current values of a blkg_rwstat
503 * @rwstat: blkg_rwstat to read
504 *
505 * Read the current snapshot of @rwstat and return it as the return value.
506 * This function can be called without synchronization and takes care of
507 * u64 atomicity.
508 */
Tejun Heoc94bed892012-04-16 13:57:22 -0700509static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
Tejun Heoedcb0722012-04-01 14:38:42 -0700510{
511 unsigned int start;
512 struct blkg_rwstat tmp;
513
514 do {
Eric W. Biederman57a77442014-03-13 21:26:42 -0700515 start = u64_stats_fetch_begin_irq(&rwstat->syncp);
Tejun Heoedcb0722012-04-01 14:38:42 -0700516 tmp = *rwstat;
Eric W. Biederman57a77442014-03-13 21:26:42 -0700517 } while (u64_stats_fetch_retry_irq(&rwstat->syncp, start));
Tejun Heoedcb0722012-04-01 14:38:42 -0700518
519 return tmp;
520}
521
522/**
Tejun Heo4d5e80a2013-01-09 08:05:12 -0800523 * blkg_rwstat_total - read the total count of a blkg_rwstat
Tejun Heoedcb0722012-04-01 14:38:42 -0700524 * @rwstat: blkg_rwstat to read
525 *
526 * Return the total count of @rwstat regardless of the IO direction. This
527 * function can be called without synchronization and takes care of u64
528 * atomicity.
529 */
Tejun Heo4d5e80a2013-01-09 08:05:12 -0800530static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
Tejun Heoedcb0722012-04-01 14:38:42 -0700531{
532 struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
533
534 return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
535}
536
537/**
538 * blkg_rwstat_reset - reset a blkg_rwstat
539 * @rwstat: blkg_rwstat to reset
540 */
541static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
542{
543 memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
544}
545
Tejun Heo16b3de62013-01-09 08:05:12 -0800546/**
547 * blkg_rwstat_merge - merge a blkg_rwstat into another
548 * @to: the destination blkg_rwstat
549 * @from: the source
550 *
551 * Add @from's counts to @to.
552 */
553static inline void blkg_rwstat_merge(struct blkg_rwstat *to,
554 struct blkg_rwstat *from)
555{
556 struct blkg_rwstat v = blkg_rwstat_read(from);
557 int i;
558
559 u64_stats_update_begin(&to->syncp);
560 for (i = 0; i < BLKG_RWSTAT_NR; i++)
561 to->cnt[i] += v.cnt[i];
562 u64_stats_update_end(&to->syncp);
563}
564
Tejun Heo36558c82012-04-16 13:57:24 -0700565#else /* CONFIG_BLK_CGROUP */
566
567struct cgroup;
Tejun Heob1208b52012-06-04 20:40:57 -0700568struct blkcg;
Jens Axboe2f5ea472009-12-03 21:06:43 +0100569
Tejun Heof95a04a2012-04-16 13:57:26 -0700570struct blkg_policy_data {
571};
572
Tejun Heo3c798392012-04-16 13:57:25 -0700573struct blkcg_gq {
Jens Axboe2f5ea472009-12-03 21:06:43 +0100574};
575
Tejun Heo3c798392012-04-16 13:57:25 -0700576struct blkcg_policy {
Vivek Goyal3e252062009-12-04 10:36:42 -0500577};
578
Tejun Heo3c798392012-04-16 13:57:25 -0700579static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
Tejun Heo5efd6112012-03-05 13:15:12 -0800580static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
581static inline void blkcg_drain_queue(struct request_queue *q) { }
582static inline void blkcg_exit_queue(struct request_queue *q) { }
Fabian Fredericka2d445d2014-06-10 20:18:36 +0200583static inline int __init blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
Tejun Heo3c798392012-04-16 13:57:25 -0700584static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
Tejun Heoa2b16932012-04-13 13:11:33 -0700585static inline int blkcg_activate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700586 const struct blkcg_policy *pol) { return 0; }
Tejun Heoa2b16932012-04-13 13:11:33 -0700587static inline void blkcg_deactivate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700588 const struct blkcg_policy *pol) { }
Vivek Goyal3e252062009-12-04 10:36:42 -0500589
Tejun Heob1208b52012-06-04 20:40:57 -0700590static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
Tejun Heoa0516612012-06-26 15:05:44 -0700591
Tejun Heof95a04a2012-04-16 13:57:26 -0700592static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
593 struct blkcg_policy *pol) { return NULL; }
594static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
Tejun Heo3c798392012-04-16 13:57:25 -0700595static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
596static inline void blkg_get(struct blkcg_gq *blkg) { }
597static inline void blkg_put(struct blkcg_gq *blkg) { }
Vivek Goyalafc24d42010-04-26 19:27:56 +0200598
Tejun Heoa0516612012-06-26 15:05:44 -0700599static inline struct request_list *blk_get_rl(struct request_queue *q,
600 struct bio *bio) { return &q->root_rl; }
601static inline void blk_put_rl(struct request_list *rl) { }
602static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
603static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
604
605#define blk_queue_for_each_rl(rl, q) \
606 for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
607
Tejun Heo36558c82012-04-16 13:57:24 -0700608#endif /* CONFIG_BLK_CGROUP */
609#endif /* _BLK_CGROUP_H */