include/linux/blk-cgroup.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _BLK_CGROUP_H
   3 #define _BLK_CGROUP_H
   4 /*
   5  * Common Block IO controller cgroup interface
   6  *
   7  * Based on ideas and code from CFQ, CFS and BFQ:
   8  * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
   9  *
  10  * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
  11  *                    Paolo Valente <paolo.valente@unimore.it>
  12  *
  13  * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
  14  *                    Nauman Rafique <nauman@google.com>
  15  */
  16
  17 #include <linux/cgroup.h>
  18 #include <linux/percpu_counter.h>
  19 #include <linux/seq_file.h>
  20 #include <linux/radix-tree.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/atomic.h>
  23
  24 /* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */
  25 #define BLKG_STAT_CPU_BATCH     (INT_MAX / 2)
  26
  27 /* Max limits for throttle policy */
  28 #define THROTL_IOPS_MAX         UINT_MAX
  29
  30 #ifdef CONFIG_BLK_CGROUP
  31
  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,
  40 };
  41
  42 struct blkcg_gq;
  43
  44 struct blkcg {
  45         struct cgroup_subsys_state      css;
  46         spinlock_t                      lock;
  47
  48         struct radix_tree_root          blkg_tree;
  49         struct blkcg_gq __rcu           *blkg_hint;
  50         struct hlist_head               blkg_list;
  51
  52         struct blkcg_policy_data        *cpd[BLKCG_MAX_POLS];
  53
  54         struct list_head                all_blkcgs_node;
  55 #ifdef CONFIG_CGROUP_WRITEBACK
  56         struct list_head                cgwb_list;
  57 #endif
  58 };
  59
  60 /*
  61  * blkg_[rw]stat->aux_cnt is excluded for local stats but included for
  62  * recursive.  Used to carry stats of dead children, and, for blkg_rwstat,
  63  * to carry result values from read and sum operations.
  64  */
  65 struct blkg_stat {
  66         struct percpu_counter           cpu_cnt;
  67         atomic64_t                      aux_cnt;
  68 };
  69
  70 struct blkg_rwstat {
  71         struct percpu_counter           cpu_cnt[BLKG_RWSTAT_NR];
  72         atomic64_t                      aux_cnt[BLKG_RWSTAT_NR];
  73 };
  74
  75 /*
  76  * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
  77  * request_queue (q).  This is used by blkcg policies which need to track
  78  * information per blkcg - q pair.
  79  *
  80  * There can be multiple active blkcg policies and each blkg:policy pair is
  81  * represented by a blkg_policy_data which is allocated and freed by each
  82  * policy's pd_alloc/free_fn() methods.  A policy can allocate private data
  83  * area by allocating larger data structure which embeds blkg_policy_data
  84  * at the beginning.
  85  */
  86 struct blkg_policy_data {
  87         /* the blkg and policy id this per-policy data belongs to */
  88         struct blkcg_gq                 *blkg;
  89         int                             plid;
  90 };
  91
  92 /*
  93  * Policies that need to keep per-blkcg data which is independent from any
  94  * request_queue associated to it should implement cpd_alloc/free_fn()
  95  * methods.  A policy can allocate private data area by allocating larger
  96  * data structure which embeds blkcg_policy_data at the beginning.
  97  * cpd_init() is invoked to let each policy handle per-blkcg data.
  98  */
  99 struct blkcg_policy_data {
 100         /* the blkcg and policy id this per-policy data belongs to */
 101         struct blkcg                    *blkcg;
 102         int                             plid;
 103 };
 104
 105 /* association between a blk cgroup and a request queue */
 106 struct blkcg_gq {
 107         /* Pointer to the associated request_queue */
 108         struct request_queue            *q;
 109         struct list_head                q_node;
 110         struct hlist_node               blkcg_node;
 111         struct blkcg                    *blkcg;
 112
 113         /*
 114          * Each blkg gets congested separately and the congestion state is
 115          * propagated to the matching bdi_writeback_congested.
 116          */
 117         struct bdi_writeback_congested  *wb_congested;
 118
 119         /* all non-root blkcg_gq's are guaranteed to have access to parent */
 120         struct blkcg_gq                 *parent;
 121
 122         /* request allocation list for this blkcg-q pair */
 123         struct request_list             rl;
 124
 125         /* reference count */
 126         atomic_t                        refcnt;
 127
 128         /* is this blkg online? protected by both blkcg and q locks */
 129         bool                            online;
 130
 131         struct blkg_rwstat              stat_bytes;
 132         struct blkg_rwstat              stat_ios;
 133
 134         struct blkg_policy_data         *pd[BLKCG_MAX_POLS];
 135
 136         struct rcu_head                 rcu_head;
 137 };
 138
 139 typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp);
 140 typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd);
 141 typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd);
 142 typedef void (blkcg_pol_bind_cpd_fn)(struct blkcg_policy_data *cpd);
 143 typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, int node);
 144 typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd);
 145 typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);
 146 typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd);
 147 typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);
 148 typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd);
 149
 150 struct blkcg_policy {
 151         int                             plid;
 152         /* cgroup files for the policy */
 153         struct cftype                   *dfl_cftypes;
 154         struct cftype                   *legacy_cftypes;
 155
 156         /* operations */
 157         blkcg_pol_alloc_cpd_fn          *cpd_alloc_fn;
 158         blkcg_pol_init_cpd_fn           *cpd_init_fn;
 159         blkcg_pol_free_cpd_fn           *cpd_free_fn;
 160         blkcg_pol_bind_cpd_fn           *cpd_bind_fn;
 161
 162         blkcg_pol_alloc_pd_fn           *pd_alloc_fn;
 163         blkcg_pol_init_pd_fn            *pd_init_fn;
 164         blkcg_pol_online_pd_fn          *pd_online_fn;
 165         blkcg_pol_offline_pd_fn         *pd_offline_fn;
 166         blkcg_pol_free_pd_fn            *pd_free_fn;
 167         blkcg_pol_reset_pd_stats_fn     *pd_reset_stats_fn;
 168 };
 169
 170 extern struct blkcg blkcg_root;
 171 extern struct cgroup_subsys_state * const blkcg_root_css;
 172
 173 struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg,
 174                                       struct request_queue *q, bool update_hint);
 175 struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
 176                                     struct request_queue *q);
 177 int blkcg_init_queue(struct request_queue *q);
 178 void blkcg_drain_queue(struct request_queue *q);
 179 void blkcg_exit_queue(struct request_queue *q);
 180
 181 /* Blkio controller policy registration */
 182 int blkcg_policy_register(struct blkcg_policy *pol);
 183 void blkcg_policy_unregister(struct blkcg_policy *pol);
 184 int blkcg_activate_policy(struct request_queue *q,
 185                           const struct blkcg_policy *pol);
 186 void blkcg_deactivate_policy(struct request_queue *q,
 187                              const struct blkcg_policy *pol);
 188
 189 const char *blkg_dev_name(struct blkcg_gq *blkg);
 190 void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
 191                        u64 (*prfill)(struct seq_file *,
 192                                      struct blkg_policy_data *, int),
 193                        const struct blkcg_policy *pol, int data,
 194                        bool show_total);
 195 u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
 196 u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
 197                          const struct blkg_rwstat *rwstat);
 198 u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
 199 u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
 200                        int off);
 201 int blkg_print_stat_bytes(struct seq_file *sf, void *v);
 202 int blkg_print_stat_ios(struct seq_file *sf, void *v);
 203 int blkg_print_stat_bytes_recursive(struct seq_file *sf, void *v);
 204 int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v);
 205
 206 u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg,
 207                             struct blkcg_policy *pol, int off);
 208 struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkcg_gq *blkg,
 209                                              struct blkcg_policy *pol, int off);
 210
 211 struct blkg_conf_ctx {
 212         struct gendisk                  *disk;
 213         struct blkcg_gq                 *blkg;
 214         char                            *body;
 215 };
 216
 217 int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 218                    char *input, struct blkg_conf_ctx *ctx);
 219 void blkg_conf_finish(struct blkg_conf_ctx *ctx);
 220
 221
 222 static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
 223 {
 224         return css ? container_of(css, struct blkcg, css) : NULL;
 225 }
 226
 227 static inline struct blkcg *task_blkcg(struct task_struct *tsk)
 228 {
 229         return css_to_blkcg(task_css(tsk, io_cgrp_id));
 230 }
 231
 232 static inline struct blkcg *bio_blkcg(struct bio *bio)
 233 {
 234         if (bio && bio->bi_css)
 235                 return css_to_blkcg(bio->bi_css);
 236         return task_blkcg(current);
 237 }
 238
 239 static inline struct cgroup_subsys_state *
 240 task_get_blkcg_css(struct task_struct *task)
 241 {
 242         return task_get_css(task, io_cgrp_id);
 243 }
 244
 245 /**
 246  * blkcg_parent - get the parent of a blkcg
 247  * @blkcg: blkcg of interest
 248  *
 249  * Return the parent blkcg of @blkcg.  Can be called anytime.
 250  */
 251 static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
 252 {
 253         return css_to_blkcg(blkcg->css.parent);
 254 }
 255
 256 /**
 257  * __blkg_lookup - internal version of blkg_lookup()
 258  * @blkcg: blkcg of interest
 259  * @q: request_queue of interest
 260  * @update_hint: whether to update lookup hint with the result or not
 261  *
 262  * This is internal version and shouldn't be used by policy
 263  * implementations.  Looks up blkgs for the @blkcg - @q pair regardless of
 264  * @q's bypass state.  If @update_hint is %true, the caller should be
 265  * holding @q->queue_lock and lookup hint is updated on success.
 266  */
 267 static inline struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
 268                                              struct request_queue *q,
 269                                              bool update_hint)
 270 {
 271         struct blkcg_gq *blkg;
 272
 273         if (blkcg == &blkcg_root)
 274                 return q->root_blkg;
 275
 276         blkg = rcu_dereference(blkcg->blkg_hint);
 277         if (blkg && blkg->q == q)
 278                 return blkg;
 279
 280         return blkg_lookup_slowpath(blkcg, q, update_hint);
 281 }
 282
 283 /**
 284  * blkg_lookup - lookup blkg for the specified blkcg - q pair
 285  * @blkcg: blkcg of interest
 286  * @q: request_queue of interest
 287  *
 288  * Lookup blkg for the @blkcg - @q pair.  This function should be called
 289  * under RCU read lock and is guaranteed to return %NULL if @q is bypassing
 290  * - see blk_queue_bypass_start() for details.
 291  */
 292 static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
 293                                            struct request_queue *q)
 294 {
 295         WARN_ON_ONCE(!rcu_read_lock_held());
 296
 297         if (unlikely(blk_queue_bypass(q)))
 298                 return NULL;
 299         return __blkg_lookup(blkcg, q, false);
 300 }
 301
 302 /**
 303  * blkg_to_pdata - get policy private data
 304  * @blkg: blkg of interest
 305  * @pol: policy of interest
 306  *
 307  * Return pointer to private data associated with the @blkg-@pol pair.
 308  */
 309 static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
 310                                                   struct blkcg_policy *pol)
 311 {
 312         return blkg ? blkg->pd[pol->plid] : NULL;
 313 }
 314
 315 static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg,
 316                                                      struct blkcg_policy *pol)
 317 {
 318         return blkcg ? blkcg->cpd[pol->plid] : NULL;
 319 }
 320
 321 /**
 322  * pdata_to_blkg - get blkg associated with policy private data
 323  * @pd: policy private data of interest
 324  *
 325  * @pd is policy private data.  Determine the blkg it's associated with.
 326  */
 327 static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
 328 {
 329         return pd ? pd->blkg : NULL;
 330 }
 331
 332 static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd)
 333 {
 334         return cpd ? cpd->blkcg : NULL;
 335 }
 336
 337 /**
 338  * blkg_path - format cgroup path of blkg
 339  * @blkg: blkg of interest
 340  * @buf: target buffer
 341  * @buflen: target buffer length
 342  *
 343  * Format the path of the cgroup of @blkg into @buf.
 344  */
 345 static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
 346 {
 347         return cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
 348 }
 349
 350 /**
 351  * blkg_get - get a blkg reference
 352  * @blkg: blkg to get
 353  *
 354  * The caller should be holding an existing reference.
 355  */
 356 static inline void blkg_get(struct blkcg_gq *blkg)
 357 {
 358         WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
 359         atomic_inc(&blkg->refcnt);
 360 }
 361
 362 void __blkg_release_rcu(struct rcu_head *rcu);
 363
 364 /**
 365  * blkg_put - put a blkg reference
 366  * @blkg: blkg to put
 367  */
 368 static inline void blkg_put(struct blkcg_gq *blkg)
 369 {
 370         WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
 371         if (atomic_dec_and_test(&blkg->refcnt))
 372                 call_rcu(&blkg->rcu_head, __blkg_release_rcu);
 373 }
 374
 375 /**
 376  * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
 377  * @d_blkg: loop cursor pointing to the current descendant
 378  * @pos_css: used for iteration
 379  * @p_blkg: target blkg to walk descendants of
 380  *
 381  * Walk @c_blkg through the descendants of @p_blkg.  Must be used with RCU
 382  * read locked.  If called under either blkcg or queue lock, the iteration
 383  * is guaranteed to include all and only online blkgs.  The caller may
 384  * update @pos_css by calling css_rightmost_descendant() to skip subtree.
 385  * @p_blkg is included in the iteration and the first node to be visited.
 386  */
 387 #define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg)           \
 388         css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css)   \
 389                 if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css),    \
 390                                               (p_blkg)->q, false)))
 391
 392 /**
 393  * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
 394  * @d_blkg: loop cursor pointing to the current descendant
 395  * @pos_css: used for iteration
 396  * @p_blkg: target blkg to walk descendants of
 397  *
 398  * Similar to blkg_for_each_descendant_pre() but performs post-order
 399  * traversal instead.  Synchronization rules are the same.  @p_blkg is
 400  * included in the iteration and the last node to be visited.
 401  */
 402 #define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg)          \
 403         css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css)  \
 404                 if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css),    \
 405                                               (p_blkg)->q, false)))
 406
 407 /**
 408  * blk_get_rl - get request_list to use
 409  * @q: request_queue of interest
 410  * @bio: bio which will be attached to the allocated request (may be %NULL)
 411  *
 412  * The caller wants to allocate a request from @q to use for @bio.  Find
 413  * the request_list to use and obtain a reference on it.  Should be called
 414  * under queue_lock.  This function is guaranteed to return non-%NULL
 415  * request_list.
 416  */
 417 static inline struct request_list *blk_get_rl(struct request_queue *q,
 418                                               struct bio *bio)
 419 {
 420         struct blkcg *blkcg;
 421         struct blkcg_gq *blkg;
 422
 423         rcu_read_lock();
 424
 425         blkcg = bio_blkcg(bio);
 426
 427         /* bypass blkg lookup and use @q->root_rl directly for root */
 428         if (blkcg == &blkcg_root)
 429                 goto root_rl;
 430
 431         /*
 432          * Try to use blkg->rl.  blkg lookup may fail under memory pressure
 433          * or if either the blkcg or queue is going away.  Fall back to
 434          * root_rl in such cases.
 435          */
 436         blkg = blkg_lookup(blkcg, q);
 437         if (unlikely(!blkg))
 438                 goto root_rl;
 439
 440         blkg_get(blkg);
 441         rcu_read_unlock();
 442         return &blkg->rl;
 443 root_rl:
 444         rcu_read_unlock();
 445         return &q->root_rl;
 446 }
 447
 448 /**
 449  * blk_put_rl - put request_list
 450  * @rl: request_list to put
 451  *
 452  * Put the reference acquired by blk_get_rl().  Should be called under
 453  * queue_lock.
 454  */
 455 static inline void blk_put_rl(struct request_list *rl)
 456 {
 457         if (rl->blkg->blkcg != &blkcg_root)
 458                 blkg_put(rl->blkg);
 459 }
 460
 461 /**
 462  * blk_rq_set_rl - associate a request with a request_list
 463  * @rq: request of interest
 464  * @rl: target request_list
 465  *
 466  * Associate @rq with @rl so that accounting and freeing can know the
 467  * request_list @rq came from.
 468  */
 469 static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
 470 {
 471         rq->rl = rl;
 472 }
 473
 474 /**
 475  * blk_rq_rl - return the request_list a request came from
 476  * @rq: request of interest
 477  *
 478  * Return the request_list @rq is allocated from.
 479  */
 480 static inline struct request_list *blk_rq_rl(struct request *rq)
 481 {
 482         return rq->rl;
 483 }
 484
 485 struct request_list *__blk_queue_next_rl(struct request_list *rl,
 486                                          struct request_queue *q);
 487 /**
 488  * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
 489  *
 490  * Should be used under queue_lock.
 491  */
 492 #define blk_queue_for_each_rl(rl, q)    \
 493         for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
 494
 495 static inline int blkg_stat_init(struct blkg_stat *stat, gfp_t gfp)
 496 {
 497         int ret;
 498
 499         ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp);
 500         if (ret)
 501                 return ret;
 502
 503         atomic64_set(&stat->aux_cnt, 0);
 504         return 0;
 505 }
 506
 507 static inline void blkg_stat_exit(struct blkg_stat *stat)
 508 {
 509         percpu_counter_destroy(&stat->cpu_cnt);
 510 }
 511
 512 /**
 513  * blkg_stat_add - add a value to a blkg_stat
 514  * @stat: target blkg_stat
 515  * @val: value to add
 516  *
 517  * Add @val to @stat.  The caller must ensure that IRQ on the same CPU
 518  * don't re-enter this function for the same counter.
 519  */
 520 static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
 521 {
 522         percpu_counter_add_batch(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
 523 }
 524
 525 /**
 526  * blkg_stat_read - read the current value of a blkg_stat
 527  * @stat: blkg_stat to read
 528  */
 529 static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
 530 {
 531         return percpu_counter_sum_positive(&stat->cpu_cnt);
 532 }
 533
 534 /**
 535  * blkg_stat_reset - reset a blkg_stat
 536  * @stat: blkg_stat to reset
 537  */
 538 static inline void blkg_stat_reset(struct blkg_stat *stat)
 539 {
 540         percpu_counter_set(&stat->cpu_cnt, 0);
 541         atomic64_set(&stat->aux_cnt, 0);
 542 }
 543
 544 /**
 545  * blkg_stat_add_aux - add a blkg_stat into another's aux count
 546  * @to: the destination blkg_stat
 547  * @from: the source
 548  *
 549  * Add @from's count including the aux one to @to's aux count.
 550  */
 551 static inline void blkg_stat_add_aux(struct blkg_stat *to,
 552                                      struct blkg_stat *from)
 553 {
 554         atomic64_add(blkg_stat_read(from) + atomic64_read(&from->aux_cnt),
 555                      &to->aux_cnt);
 556 }
 557
 558 static inline int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
 559 {
 560         int i, ret;
 561
 562         for (i = 0; i < BLKG_RWSTAT_NR; i++) {
 563                 ret = percpu_counter_init(&rwstat->cpu_cnt[i], 0, gfp);
 564                 if (ret) {
 565                         while (--i >= 0)
 566                                 percpu_counter_destroy(&rwstat->cpu_cnt[i]);
 567                         return ret;
 568                 }
 569                 atomic64_set(&rwstat->aux_cnt[i], 0);
 570         }
 571         return 0;
 572 }
 573
 574 static inline void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
 575 {
 576         int i;
 577
 578         for (i = 0; i < BLKG_RWSTAT_NR; i++)
 579                 percpu_counter_destroy(&rwstat->cpu_cnt[i]);
 580 }
 581
 582 /**
 583  * blkg_rwstat_add - add a value to a blkg_rwstat
 584  * @rwstat: target blkg_rwstat
 585  * @op: REQ_OP and flags
 586  * @val: value to add
 587  *
 588  * Add @val to @rwstat.  The counters are chosen according to @rw.  The
 589  * caller is responsible for synchronizing calls to this function.
 590  */
 591 static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
 592                                    unsigned int op, uint64_t val)
 593 {
 594         struct percpu_counter *cnt;
 595
 596         if (op_is_write(op))
 597                 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE];
 598         else
 599                 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ];
 600
 601         percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH);
 602
 603         if (op_is_sync(op))
 604                 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC];
 605         else
 606                 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC];
 607
 608         percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH);
 609 }
 610
 611 /**
 612  * blkg_rwstat_read - read the current values of a blkg_rwstat
 613  * @rwstat: blkg_rwstat to read
 614  *
 615  * Read the current snapshot of @rwstat and return it in the aux counts.
 616  */
 617 static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
 618 {
 619         struct blkg_rwstat result;
 620         int i;
 621
 622         for (i = 0; i < BLKG_RWSTAT_NR; i++)
 623                 atomic64_set(&result.aux_cnt[i],
 624                              percpu_counter_sum_positive(&rwstat->cpu_cnt[i]));
 625         return result;
 626 }
 627
 628 /**
 629  * blkg_rwstat_total - read the total count of a blkg_rwstat
 630  * @rwstat: blkg_rwstat to read
 631  *
 632  * Return the total count of @rwstat regardless of the IO direction.  This
 633  * function can be called without synchronization and takes care of u64
 634  * atomicity.
 635  */
 636 static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
 637 {
 638         struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
 639
 640         return atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
 641                 atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
 642 }
 643
 644 /**
 645  * blkg_rwstat_reset - reset a blkg_rwstat
 646  * @rwstat: blkg_rwstat to reset
 647  */
 648 static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
 649 {
 650         int i;
 651
 652         for (i = 0; i < BLKG_RWSTAT_NR; i++) {
 653                 percpu_counter_set(&rwstat->cpu_cnt[i], 0);
 654                 atomic64_set(&rwstat->aux_cnt[i], 0);
 655         }
 656 }
 657
 658 /**
 659  * blkg_rwstat_add_aux - add a blkg_rwstat into another's aux count
 660  * @to: the destination blkg_rwstat
 661  * @from: the source
 662  *
 663  * Add @from's count including the aux one to @to's aux count.
 664  */
 665 static inline void blkg_rwstat_add_aux(struct blkg_rwstat *to,
 666                                        struct blkg_rwstat *from)
 667 {
 668         struct blkg_rwstat v = blkg_rwstat_read(from);
 669         int i;
 670
 671         for (i = 0; i < BLKG_RWSTAT_NR; i++)
 672                 atomic64_add(atomic64_read(&v.aux_cnt[i]) +
 673                              atomic64_read(&from->aux_cnt[i]),
 674                              &to->aux_cnt[i]);
 675 }
 676
 677 #ifdef CONFIG_BLK_DEV_THROTTLING
 678 extern bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
 679                            struct bio *bio);
 680 #else
 681 static inline bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
 682                                   struct bio *bio) { return false; }
 683 #endif
 684
 685 static inline bool blkcg_bio_issue_check(struct request_queue *q,
 686                                          struct bio *bio)
 687 {
 688         struct blkcg *blkcg;
 689         struct blkcg_gq *blkg;
 690         bool throtl = false;
 691
 692         rcu_read_lock();
 693         blkcg = bio_blkcg(bio);
 694
 695         /* associate blkcg if bio hasn't attached one */
 696         bio_associate_blkcg(bio, &blkcg->css);
 697
 698         blkg = blkg_lookup(blkcg, q);
 699         if (unlikely(!blkg)) {
 700                 spin_lock_irq(q->queue_lock);
 701                 blkg = blkg_lookup_create(blkcg, q);
 702                 if (IS_ERR(blkg))
 703                         blkg = NULL;
 704                 spin_unlock_irq(q->queue_lock);
 705         }
 706
 707         throtl = blk_throtl_bio(q, blkg, bio);
 708
 709         if (!throtl) {
 710                 blkg = blkg ?: q->root_blkg;
 711                 blkg_rwstat_add(&blkg->stat_bytes, bio->bi_opf,
 712                                 bio->bi_iter.bi_size);
 713                 blkg_rwstat_add(&blkg->stat_ios, bio->bi_opf, 1);
 714         }
 715
 716         rcu_read_unlock();
 717         return !throtl;
 718 }
 719
 720 #else   /* CONFIG_BLK_CGROUP */
 721
 722 struct blkcg {
 723 };
 724
 725 struct blkg_policy_data {
 726 };
 727
 728 struct blkcg_policy_data {
 729 };
 730
 731 struct blkcg_gq {
 732 };
 733
 734 struct blkcg_policy {
 735 };
 736
 737 #define blkcg_root_css  ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))
 738
 739 static inline struct cgroup_subsys_state *
 740 task_get_blkcg_css(struct task_struct *task)
 741 {
 742         return NULL;
 743 }
 744
 745 #ifdef CONFIG_BLOCK
 746
 747 static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
 748 static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
 749 static inline void blkcg_drain_queue(struct request_queue *q) { }
 750 static inline void blkcg_exit_queue(struct request_queue *q) { }
 751 static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
 752 static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
 753 static inline int blkcg_activate_policy(struct request_queue *q,
 754                                         const struct blkcg_policy *pol) { return 0; }
 755 static inline void blkcg_deactivate_policy(struct request_queue *q,
 756                                            const struct blkcg_policy *pol) { }
 757
 758 static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
 759
 760 static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
 761                                                   struct blkcg_policy *pol) { return NULL; }
 762 static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
 763 static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
 764 static inline void blkg_get(struct blkcg_gq *blkg) { }
 765 static inline void blkg_put(struct blkcg_gq *blkg) { }
 766
 767 static inline struct request_list *blk_get_rl(struct request_queue *q,
 768                                               struct bio *bio) { return &q->root_rl; }
 769 static inline void blk_put_rl(struct request_list *rl) { }
 770 static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
 771 static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
 772
 773 static inline bool blkcg_bio_issue_check(struct request_queue *q,
 774                                          struct bio *bio) { return true; }
 775
 776 #define blk_queue_for_each_rl(rl, q)    \
 777         for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
 778
 779 #endif  /* CONFIG_BLOCK */
 780 #endif  /* CONFIG_BLK_CGROUP */
 781 #endif  /* _BLK_CGROUP_H */