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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>
Tejun Heoa5049a82014-06-19 17:42:57 -040021#include <linux/atomic.h>
Vivek Goyal31e4c282009-12-03 12:59:42 -050022
Vivek Goyal9355aed2010-10-01 21:16:41 +020023/* Max limits for throttle policy */
24#define THROTL_IOPS_MAX UINT_MAX
25
Tejun Heo3381cb82012-04-01 14:38:44 -070026/* CFQ specific, out here for blkcg->cfq_weight */
27#define CFQ_WEIGHT_MIN 10
28#define CFQ_WEIGHT_MAX 1000
29#define CFQ_WEIGHT_DEFAULT 500
30
Tejun Heof48ec1d2012-04-13 13:11:25 -070031#ifdef CONFIG_BLK_CGROUP
32
Tejun Heoedcb0722012-04-01 14:38:42 -070033enum blkg_rwstat_type {
34 BLKG_RWSTAT_READ,
35 BLKG_RWSTAT_WRITE,
36 BLKG_RWSTAT_SYNC,
37 BLKG_RWSTAT_ASYNC,
38
39 BLKG_RWSTAT_NR,
40 BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
Divyesh Shah303a3ac2010-04-01 15:01:24 -070041};
42
Tejun Heoa6371202012-04-19 16:29:24 -070043struct blkcg_gq;
44
Tejun Heo3c798392012-04-16 13:57:25 -070045struct blkcg {
Tejun Heo36558c82012-04-16 13:57:24 -070046 struct cgroup_subsys_state css;
47 spinlock_t lock;
Tejun Heoa6371202012-04-19 16:29:24 -070048
49 struct radix_tree_root blkg_tree;
50 struct blkcg_gq *blkg_hint;
Tejun Heo36558c82012-04-16 13:57:24 -070051 struct hlist_head blkg_list;
Tejun Heo9a9e8a22012-03-19 15:10:56 -070052
53 /* for policies to test whether associated blkcg has changed */
Tejun Heo36558c82012-04-16 13:57:24 -070054 uint64_t id;
Tejun Heo3381cb82012-04-01 14:38:44 -070055
Tejun Heo3c798392012-04-16 13:57:25 -070056 /* TODO: per-policy storage in blkcg */
Tejun Heo36558c82012-04-16 13:57:24 -070057 unsigned int cfq_weight; /* belongs to cfq */
Tejun Heoe71357e2013-01-09 08:05:10 -080058 unsigned int cfq_leaf_weight;
Vivek Goyal31e4c282009-12-03 12:59:42 -050059};
60
Tejun Heoedcb0722012-04-01 14:38:42 -070061struct blkg_stat {
62 struct u64_stats_sync syncp;
63 uint64_t cnt;
64};
65
66struct blkg_rwstat {
67 struct u64_stats_sync syncp;
68 uint64_t cnt[BLKG_RWSTAT_NR];
69};
70
Tejun Heof95a04a2012-04-16 13:57:26 -070071/*
72 * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
73 * request_queue (q). This is used by blkcg policies which need to track
74 * information per blkcg - q pair.
75 *
76 * There can be multiple active blkcg policies and each has its private
77 * data on each blkg, the size of which is determined by
78 * blkcg_policy->pd_size. blkcg core allocates and frees such areas
79 * together with blkg and invokes pd_init/exit_fn() methods.
80 *
81 * Such private data must embed struct blkg_policy_data (pd) at the
82 * beginning and pd_size can't be smaller than pd.
83 */
Tejun Heo03814112012-03-05 13:15:14 -080084struct blkg_policy_data {
Tejun Heob276a872013-01-09 08:05:12 -080085 /* the blkg and policy id this per-policy data belongs to */
Tejun Heo3c798392012-04-16 13:57:25 -070086 struct blkcg_gq *blkg;
Tejun Heob276a872013-01-09 08:05:12 -080087 int plid;
Tejun Heo03814112012-03-05 13:15:14 -080088
Tejun Heoa2b16932012-04-13 13:11:33 -070089 /* used during policy activation */
Tejun Heo36558c82012-04-16 13:57:24 -070090 struct list_head alloc_node;
Tejun Heo03814112012-03-05 13:15:14 -080091};
92
Tejun Heo3c798392012-04-16 13:57:25 -070093/* association between a blk cgroup and a request queue */
94struct blkcg_gq {
Tejun Heoc875f4d2012-03-05 13:15:22 -080095 /* Pointer to the associated request_queue */
Tejun Heo36558c82012-04-16 13:57:24 -070096 struct request_queue *q;
97 struct list_head q_node;
98 struct hlist_node blkcg_node;
Tejun Heo3c798392012-04-16 13:57:25 -070099 struct blkcg *blkcg;
Tejun Heo3c547862013-01-09 08:05:10 -0800100
101 /* all non-root blkcg_gq's are guaranteed to have access to parent */
102 struct blkcg_gq *parent;
103
Tejun Heoa0516612012-06-26 15:05:44 -0700104 /* request allocation list for this blkcg-q pair */
105 struct request_list rl;
Tejun Heo3c547862013-01-09 08:05:10 -0800106
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800107 /* reference count */
Tejun Heoa5049a82014-06-19 17:42:57 -0400108 atomic_t refcnt;
Vivek Goyal22084192009-12-03 12:59:49 -0500109
Tejun Heof427d902013-01-09 08:05:12 -0800110 /* is this blkg online? protected by both blkcg and q locks */
111 bool online;
112
Tejun Heo36558c82012-04-16 13:57:24 -0700113 struct blkg_policy_data *pd[BLKCG_MAX_POLS];
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800114
Tejun Heo36558c82012-04-16 13:57:24 -0700115 struct rcu_head rcu_head;
Vivek Goyal31e4c282009-12-03 12:59:42 -0500116};
117
Tejun Heo3c798392012-04-16 13:57:25 -0700118typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
Tejun Heof427d902013-01-09 08:05:12 -0800119typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg);
120typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg);
Tejun Heo3c798392012-04-16 13:57:25 -0700121typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
122typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
Vivek Goyal3e252062009-12-04 10:36:42 -0500123
Tejun Heo3c798392012-04-16 13:57:25 -0700124struct blkcg_policy {
Tejun Heo36558c82012-04-16 13:57:24 -0700125 int plid;
126 /* policy specific private data size */
Tejun Heof95a04a2012-04-16 13:57:26 -0700127 size_t pd_size;
Tejun Heo36558c82012-04-16 13:57:24 -0700128 /* cgroup files for the policy */
129 struct cftype *cftypes;
Tejun Heof9fcc2d2012-04-16 13:57:27 -0700130
131 /* operations */
132 blkcg_pol_init_pd_fn *pd_init_fn;
Tejun Heof427d902013-01-09 08:05:12 -0800133 blkcg_pol_online_pd_fn *pd_online_fn;
134 blkcg_pol_offline_pd_fn *pd_offline_fn;
Tejun Heof9fcc2d2012-04-16 13:57:27 -0700135 blkcg_pol_exit_pd_fn *pd_exit_fn;
136 blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
Vivek Goyal3e252062009-12-04 10:36:42 -0500137};
138
Tejun Heo3c798392012-04-16 13:57:25 -0700139extern struct blkcg blkcg_root;
Tejun Heo36558c82012-04-16 13:57:24 -0700140
Tejun Heo3c798392012-04-16 13:57:25 -0700141struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
142struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
143 struct request_queue *q);
Tejun Heo36558c82012-04-16 13:57:24 -0700144int blkcg_init_queue(struct request_queue *q);
145void blkcg_drain_queue(struct request_queue *q);
146void blkcg_exit_queue(struct request_queue *q);
Tejun Heo5efd6112012-03-05 13:15:12 -0800147
Vivek Goyal3e252062009-12-04 10:36:42 -0500148/* Blkio controller policy registration */
Jens Axboed5bf0292014-06-22 16:31:56 -0600149int blkcg_policy_register(struct blkcg_policy *pol);
Tejun Heo3c798392012-04-16 13:57:25 -0700150void blkcg_policy_unregister(struct blkcg_policy *pol);
Tejun Heo36558c82012-04-16 13:57:24 -0700151int blkcg_activate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700152 const struct blkcg_policy *pol);
Tejun Heo36558c82012-04-16 13:57:24 -0700153void blkcg_deactivate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700154 const struct blkcg_policy *pol);
Vivek Goyal3e252062009-12-04 10:36:42 -0500155
Tejun Heo3c798392012-04-16 13:57:25 -0700156void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
Tejun Heof95a04a2012-04-16 13:57:26 -0700157 u64 (*prfill)(struct seq_file *,
158 struct blkg_policy_data *, int),
Tejun Heo3c798392012-04-16 13:57:25 -0700159 const struct blkcg_policy *pol, int data,
Tejun Heoec399342012-04-13 13:11:27 -0700160 bool show_total);
Tejun Heof95a04a2012-04-16 13:57:26 -0700161u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
162u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
Tejun Heo829fdb52012-04-01 14:38:43 -0700163 const struct blkg_rwstat *rwstat);
Tejun Heof95a04a2012-04-16 13:57:26 -0700164u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
165u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
166 int off);
Tejun Heo829fdb52012-04-01 14:38:43 -0700167
Tejun Heo16b3de62013-01-09 08:05:12 -0800168u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off);
169struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
170 int off);
171
Tejun Heo829fdb52012-04-01 14:38:43 -0700172struct blkg_conf_ctx {
Tejun Heo36558c82012-04-16 13:57:24 -0700173 struct gendisk *disk;
Tejun Heo3c798392012-04-16 13:57:25 -0700174 struct blkcg_gq *blkg;
Tejun Heo36558c82012-04-16 13:57:24 -0700175 u64 v;
Tejun Heo829fdb52012-04-01 14:38:43 -0700176};
177
Tejun Heo3c798392012-04-16 13:57:25 -0700178int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
179 const char *input, struct blkg_conf_ctx *ctx);
Tejun Heo829fdb52012-04-01 14:38:43 -0700180void blkg_conf_finish(struct blkg_conf_ctx *ctx);
181
182
Tejun Heoa7c6d552013-08-08 20:11:23 -0400183static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
184{
185 return css ? container_of(css, struct blkcg, css) : NULL;
186}
187
Tejun Heob1208b52012-06-04 20:40:57 -0700188static inline struct blkcg *task_blkcg(struct task_struct *tsk)
189{
Tejun Heo073219e2014-02-08 10:36:58 -0500190 return css_to_blkcg(task_css(tsk, blkio_cgrp_id));
Tejun Heob1208b52012-06-04 20:40:57 -0700191}
192
193static inline struct blkcg *bio_blkcg(struct bio *bio)
194{
195 if (bio && bio->bi_css)
Tejun Heoa7c6d552013-08-08 20:11:23 -0400196 return css_to_blkcg(bio->bi_css);
Tejun Heob1208b52012-06-04 20:40:57 -0700197 return task_blkcg(current);
198}
199
Tejun Heo03814112012-03-05 13:15:14 -0800200/**
Tejun Heo3c547862013-01-09 08:05:10 -0800201 * blkcg_parent - get the parent of a blkcg
202 * @blkcg: blkcg of interest
203 *
204 * Return the parent blkcg of @blkcg. Can be called anytime.
205 */
206static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
207{
Tejun Heo5c9d5352014-05-16 13:22:48 -0400208 return css_to_blkcg(blkcg->css.parent);
Tejun Heo3c547862013-01-09 08:05:10 -0800209}
210
211/**
Tejun Heo03814112012-03-05 13:15:14 -0800212 * blkg_to_pdata - get policy private data
213 * @blkg: blkg of interest
214 * @pol: policy of interest
215 *
216 * Return pointer to private data associated with the @blkg-@pol pair.
217 */
Tejun Heof95a04a2012-04-16 13:57:26 -0700218static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
219 struct blkcg_policy *pol)
Tejun Heo03814112012-03-05 13:15:14 -0800220{
Tejun Heof95a04a2012-04-16 13:57:26 -0700221 return blkg ? blkg->pd[pol->plid] : NULL;
Tejun Heo03814112012-03-05 13:15:14 -0800222}
223
224/**
225 * pdata_to_blkg - get blkg associated with policy private data
Tejun Heof95a04a2012-04-16 13:57:26 -0700226 * @pd: policy private data of interest
Tejun Heo03814112012-03-05 13:15:14 -0800227 *
Tejun Heof95a04a2012-04-16 13:57:26 -0700228 * @pd is policy private data. Determine the blkg it's associated with.
Tejun Heo03814112012-03-05 13:15:14 -0800229 */
Tejun Heof95a04a2012-04-16 13:57:26 -0700230static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
Tejun Heo03814112012-03-05 13:15:14 -0800231{
Tejun Heof95a04a2012-04-16 13:57:26 -0700232 return pd ? pd->blkg : NULL;
Tejun Heo03814112012-03-05 13:15:14 -0800233}
234
Tejun Heo54e7ed12012-04-16 13:57:23 -0700235/**
236 * blkg_path - format cgroup path of blkg
237 * @blkg: blkg of interest
238 * @buf: target buffer
239 * @buflen: target buffer length
240 *
241 * Format the path of the cgroup of @blkg into @buf.
242 */
Tejun Heo3c798392012-04-16 13:57:25 -0700243static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
Vivek Goyalafc24d42010-04-26 19:27:56 +0200244{
Tejun Heoe61734c2014-02-12 09:29:50 -0500245 char *p;
Tejun Heo54e7ed12012-04-16 13:57:23 -0700246
Tejun Heoe61734c2014-02-12 09:29:50 -0500247 p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
248 if (!p) {
Tejun Heo54e7ed12012-04-16 13:57:23 -0700249 strncpy(buf, "<unavailable>", buflen);
Tejun Heoe61734c2014-02-12 09:29:50 -0500250 return -ENAMETOOLONG;
251 }
252
253 memmove(buf, p, buf + buflen - p);
254 return 0;
Vivek Goyalafc24d42010-04-26 19:27:56 +0200255}
256
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800257/**
258 * blkg_get - get a blkg reference
259 * @blkg: blkg to get
260 *
Tejun Heoa5049a82014-06-19 17:42:57 -0400261 * The caller should be holding an existing reference.
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800262 */
Tejun Heo3c798392012-04-16 13:57:25 -0700263static inline void blkg_get(struct blkcg_gq *blkg)
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800264{
Tejun Heoa5049a82014-06-19 17:42:57 -0400265 WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
266 atomic_inc(&blkg->refcnt);
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800267}
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
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800274 */
Tejun Heo3c798392012-04-16 13:57:25 -0700275static inline void blkg_put(struct blkcg_gq *blkg)
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800276{
Tejun Heoa5049a82014-06-19 17:42:57 -0400277 WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
278 if (atomic_dec_and_test(&blkg->refcnt))
Tejun Heo2a4fd072013-05-14 13:52:31 -0700279 call_rcu(&blkg->rcu_head, __blkg_release_rcu);
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800280}
281
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700282struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q,
283 bool update_hint);
284
285/**
286 * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
287 * @d_blkg: loop cursor pointing to the current descendant
Tejun Heo492eb212013-08-08 20:11:25 -0400288 * @pos_css: used for iteration
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700289 * @p_blkg: target blkg to walk descendants of
290 *
291 * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
292 * read locked. If called under either blkcg or queue lock, the iteration
293 * is guaranteed to include all and only online blkgs. The caller may
Tejun Heo492eb212013-08-08 20:11:25 -0400294 * update @pos_css by calling css_rightmost_descendant() to skip subtree.
Tejun Heobd8815a2013-08-08 20:11:27 -0400295 * @p_blkg is included in the iteration and the first node to be visited.
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700296 */
Tejun Heo492eb212013-08-08 20:11:25 -0400297#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \
298 css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \
299 if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700300 (p_blkg)->q, false)))
301
Tejun Heoedcb0722012-04-01 14:38:42 -0700302/**
Tejun Heoaa539cb2013-05-14 13:52:31 -0700303 * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
304 * @d_blkg: loop cursor pointing to the current descendant
Tejun Heo492eb212013-08-08 20:11:25 -0400305 * @pos_css: used for iteration
Tejun Heoaa539cb2013-05-14 13:52:31 -0700306 * @p_blkg: target blkg to walk descendants of
307 *
308 * Similar to blkg_for_each_descendant_pre() but performs post-order
Tejun Heobd8815a2013-08-08 20:11:27 -0400309 * traversal instead. Synchronization rules are the same. @p_blkg is
310 * included in the iteration and the last node to be visited.
Tejun Heoaa539cb2013-05-14 13:52:31 -0700311 */
Tejun Heo492eb212013-08-08 20:11:25 -0400312#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \
313 css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \
314 if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
Tejun Heoaa539cb2013-05-14 13:52:31 -0700315 (p_blkg)->q, false)))
316
317/**
Tejun Heoa0516612012-06-26 15:05:44 -0700318 * blk_get_rl - get request_list to use
319 * @q: request_queue of interest
320 * @bio: bio which will be attached to the allocated request (may be %NULL)
321 *
322 * The caller wants to allocate a request from @q to use for @bio. Find
323 * the request_list to use and obtain a reference on it. Should be called
324 * under queue_lock. This function is guaranteed to return non-%NULL
325 * request_list.
326 */
327static inline struct request_list *blk_get_rl(struct request_queue *q,
328 struct bio *bio)
329{
330 struct blkcg *blkcg;
331 struct blkcg_gq *blkg;
332
333 rcu_read_lock();
334
335 blkcg = bio_blkcg(bio);
336
337 /* bypass blkg lookup and use @q->root_rl directly for root */
338 if (blkcg == &blkcg_root)
339 goto root_rl;
340
341 /*
342 * Try to use blkg->rl. blkg lookup may fail under memory pressure
343 * or if either the blkcg or queue is going away. Fall back to
344 * root_rl in such cases.
345 */
346 blkg = blkg_lookup_create(blkcg, q);
347 if (unlikely(IS_ERR(blkg)))
348 goto root_rl;
349
350 blkg_get(blkg);
351 rcu_read_unlock();
352 return &blkg->rl;
353root_rl:
354 rcu_read_unlock();
355 return &q->root_rl;
356}
357
358/**
359 * blk_put_rl - put request_list
360 * @rl: request_list to put
361 *
362 * Put the reference acquired by blk_get_rl(). Should be called under
363 * queue_lock.
364 */
365static inline void blk_put_rl(struct request_list *rl)
366{
367 /* root_rl may not have blkg set */
368 if (rl->blkg && rl->blkg->blkcg != &blkcg_root)
369 blkg_put(rl->blkg);
370}
371
372/**
373 * blk_rq_set_rl - associate a request with a request_list
374 * @rq: request of interest
375 * @rl: target request_list
376 *
377 * Associate @rq with @rl so that accounting and freeing can know the
378 * request_list @rq came from.
379 */
380static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
381{
382 rq->rl = rl;
383}
384
385/**
386 * blk_rq_rl - return the request_list a request came from
387 * @rq: request of interest
388 *
389 * Return the request_list @rq is allocated from.
390 */
391static inline struct request_list *blk_rq_rl(struct request *rq)
392{
393 return rq->rl;
394}
395
396struct request_list *__blk_queue_next_rl(struct request_list *rl,
397 struct request_queue *q);
398/**
399 * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
400 *
401 * Should be used under queue_lock.
402 */
403#define blk_queue_for_each_rl(rl, q) \
404 for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
405
Peter Zijlstra90d38392013-11-12 19:42:14 -0800406static inline void blkg_stat_init(struct blkg_stat *stat)
407{
408 u64_stats_init(&stat->syncp);
409}
410
Tejun Heoa0516612012-06-26 15:05:44 -0700411/**
Tejun Heoedcb0722012-04-01 14:38:42 -0700412 * blkg_stat_add - add a value to a blkg_stat
413 * @stat: target blkg_stat
414 * @val: value to add
415 *
416 * Add @val to @stat. The caller is responsible for synchronizing calls to
417 * this function.
418 */
419static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
420{
421 u64_stats_update_begin(&stat->syncp);
422 stat->cnt += val;
423 u64_stats_update_end(&stat->syncp);
424}
425
426/**
427 * blkg_stat_read - read the current value of a blkg_stat
428 * @stat: blkg_stat to read
429 *
430 * Read the current value of @stat. This function can be called without
431 * synchroniztion and takes care of u64 atomicity.
432 */
433static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
434{
435 unsigned int start;
436 uint64_t v;
437
438 do {
Eric W. Biederman57a77442014-03-13 21:26:42 -0700439 start = u64_stats_fetch_begin_irq(&stat->syncp);
Tejun Heoedcb0722012-04-01 14:38:42 -0700440 v = stat->cnt;
Eric W. Biederman57a77442014-03-13 21:26:42 -0700441 } while (u64_stats_fetch_retry_irq(&stat->syncp, start));
Tejun Heoedcb0722012-04-01 14:38:42 -0700442
443 return v;
444}
445
446/**
447 * blkg_stat_reset - reset a blkg_stat
448 * @stat: blkg_stat to reset
449 */
450static inline void blkg_stat_reset(struct blkg_stat *stat)
451{
452 stat->cnt = 0;
453}
454
455/**
Tejun Heo16b3de62013-01-09 08:05:12 -0800456 * blkg_stat_merge - merge a blkg_stat into another
457 * @to: the destination blkg_stat
458 * @from: the source
459 *
460 * Add @from's count to @to.
461 */
462static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from)
463{
464 blkg_stat_add(to, blkg_stat_read(from));
465}
466
Peter Zijlstra90d38392013-11-12 19:42:14 -0800467static inline void blkg_rwstat_init(struct blkg_rwstat *rwstat)
468{
469 u64_stats_init(&rwstat->syncp);
470}
471
Tejun Heo16b3de62013-01-09 08:05:12 -0800472/**
Tejun Heoedcb0722012-04-01 14:38:42 -0700473 * blkg_rwstat_add - add a value to a blkg_rwstat
474 * @rwstat: target blkg_rwstat
475 * @rw: mask of REQ_{WRITE|SYNC}
476 * @val: value to add
477 *
478 * Add @val to @rwstat. The counters are chosen according to @rw. The
479 * caller is responsible for synchronizing calls to this function.
480 */
481static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
482 int rw, uint64_t val)
483{
484 u64_stats_update_begin(&rwstat->syncp);
485
486 if (rw & REQ_WRITE)
487 rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
488 else
489 rwstat->cnt[BLKG_RWSTAT_READ] += val;
490 if (rw & REQ_SYNC)
491 rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
492 else
493 rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
494
495 u64_stats_update_end(&rwstat->syncp);
496}
497
498/**
499 * blkg_rwstat_read - read the current values of a blkg_rwstat
500 * @rwstat: blkg_rwstat to read
501 *
502 * Read the current snapshot of @rwstat and return it as the return value.
503 * This function can be called without synchronization and takes care of
504 * u64 atomicity.
505 */
Tejun Heoc94bed892012-04-16 13:57:22 -0700506static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
Tejun Heoedcb0722012-04-01 14:38:42 -0700507{
508 unsigned int start;
509 struct blkg_rwstat tmp;
510
511 do {
Eric W. Biederman57a77442014-03-13 21:26:42 -0700512 start = u64_stats_fetch_begin_irq(&rwstat->syncp);
Tejun Heoedcb0722012-04-01 14:38:42 -0700513 tmp = *rwstat;
Eric W. Biederman57a77442014-03-13 21:26:42 -0700514 } while (u64_stats_fetch_retry_irq(&rwstat->syncp, start));
Tejun Heoedcb0722012-04-01 14:38:42 -0700515
516 return tmp;
517}
518
519/**
Tejun Heo4d5e80a2013-01-09 08:05:12 -0800520 * blkg_rwstat_total - read the total count of a blkg_rwstat
Tejun Heoedcb0722012-04-01 14:38:42 -0700521 * @rwstat: blkg_rwstat to read
522 *
523 * Return the total count of @rwstat regardless of the IO direction. This
524 * function can be called without synchronization and takes care of u64
525 * atomicity.
526 */
Tejun Heo4d5e80a2013-01-09 08:05:12 -0800527static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
Tejun Heoedcb0722012-04-01 14:38:42 -0700528{
529 struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
530
531 return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
532}
533
534/**
535 * blkg_rwstat_reset - reset a blkg_rwstat
536 * @rwstat: blkg_rwstat to reset
537 */
538static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
539{
540 memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
541}
542
Tejun Heo16b3de62013-01-09 08:05:12 -0800543/**
544 * blkg_rwstat_merge - merge a blkg_rwstat into another
545 * @to: the destination blkg_rwstat
546 * @from: the source
547 *
548 * Add @from's counts to @to.
549 */
550static inline void blkg_rwstat_merge(struct blkg_rwstat *to,
551 struct blkg_rwstat *from)
552{
553 struct blkg_rwstat v = blkg_rwstat_read(from);
554 int i;
555
556 u64_stats_update_begin(&to->syncp);
557 for (i = 0; i < BLKG_RWSTAT_NR; i++)
558 to->cnt[i] += v.cnt[i];
559 u64_stats_update_end(&to->syncp);
560}
561
Tejun Heo36558c82012-04-16 13:57:24 -0700562#else /* CONFIG_BLK_CGROUP */
563
564struct cgroup;
Tejun Heob1208b52012-06-04 20:40:57 -0700565struct blkcg;
Jens Axboe2f5ea472009-12-03 21:06:43 +0100566
Tejun Heof95a04a2012-04-16 13:57:26 -0700567struct blkg_policy_data {
568};
569
Tejun Heo3c798392012-04-16 13:57:25 -0700570struct blkcg_gq {
Jens Axboe2f5ea472009-12-03 21:06:43 +0100571};
572
Tejun Heo3c798392012-04-16 13:57:25 -0700573struct blkcg_policy {
Vivek Goyal3e252062009-12-04 10:36:42 -0500574};
575
Tejun Heo3c798392012-04-16 13:57:25 -0700576static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
Tejun Heo5efd6112012-03-05 13:15:12 -0800577static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
578static inline void blkcg_drain_queue(struct request_queue *q) { }
579static inline void blkcg_exit_queue(struct request_queue *q) { }
Jens Axboed5bf0292014-06-22 16:31:56 -0600580static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
Tejun Heo3c798392012-04-16 13:57:25 -0700581static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
Tejun Heoa2b16932012-04-13 13:11:33 -0700582static inline int blkcg_activate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700583 const struct blkcg_policy *pol) { return 0; }
Tejun Heoa2b16932012-04-13 13:11:33 -0700584static inline void blkcg_deactivate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700585 const struct blkcg_policy *pol) { }
Vivek Goyal3e252062009-12-04 10:36:42 -0500586
Tejun Heob1208b52012-06-04 20:40:57 -0700587static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
Tejun Heoa0516612012-06-26 15:05:44 -0700588
Tejun Heof95a04a2012-04-16 13:57:26 -0700589static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
590 struct blkcg_policy *pol) { return NULL; }
591static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
Tejun Heo3c798392012-04-16 13:57:25 -0700592static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
593static inline void blkg_get(struct blkcg_gq *blkg) { }
594static inline void blkg_put(struct blkcg_gq *blkg) { }
Vivek Goyalafc24d42010-04-26 19:27:56 +0200595
Tejun Heoa0516612012-06-26 15:05:44 -0700596static inline struct request_list *blk_get_rl(struct request_queue *q,
597 struct bio *bio) { return &q->root_rl; }
598static inline void blk_put_rl(struct request_list *rl) { }
599static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
600static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
601
602#define blk_queue_for_each_rl(rl, q) \
603 for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
604
Tejun Heo36558c82012-04-16 13:57:24 -0700605#endif /* CONFIG_BLK_CGROUP */
606#endif /* _BLK_CGROUP_H */