1 /* SPDX-License-Identifier: GPL-2.0 */
5 * Common Block IO controller cgroup interface
7 * Based on ideas and code from CFQ, CFS and BFQ:
8 * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
10 * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
11 * Paolo Valente <paolo.valente@unimore.it>
13 * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
14 * Nauman Rafique <nauman@google.com>
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>
24 /* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */
25 #define BLKG_STAT_CPU_BATCH (INT_MAX / 2)
27 /* Max limits for throttle policy */
28 #define THROTL_IOPS_MAX UINT_MAX
30 #ifdef CONFIG_BLK_CGROUP
32 enum blkg_rwstat_type {
39 BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
45 struct cgroup_subsys_state css;
48 struct radix_tree_root blkg_tree;
49 struct blkcg_gq __rcu *blkg_hint;
50 struct hlist_head blkg_list;
52 struct blkcg_policy_data *cpd[BLKCG_MAX_POLS];
54 struct list_head all_blkcgs_node;
55 #ifdef CONFIG_CGROUP_WRITEBACK
56 struct list_head cgwb_list;
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.
66 struct percpu_counter cpu_cnt;
71 struct percpu_counter cpu_cnt[BLKG_RWSTAT_NR];
72 atomic64_t aux_cnt[BLKG_RWSTAT_NR];
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.
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
86 struct blkg_policy_data {
87 /* the blkg and policy id this per-policy data belongs to */
88 struct blkcg_gq *blkg;
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.
99 struct blkcg_policy_data {
100 /* the blkcg and policy id this per-policy data belongs to */
105 /* association between a blk cgroup and a request queue */
107 /* Pointer to the associated request_queue */
108 struct request_queue *q;
109 struct list_head q_node;
110 struct hlist_node blkcg_node;
114 * Each blkg gets congested separately and the congestion state is
115 * propagated to the matching bdi_writeback_congested.
117 struct bdi_writeback_congested *wb_congested;
119 /* all non-root blkcg_gq's are guaranteed to have access to parent */
120 struct blkcg_gq *parent;
122 /* request allocation list for this blkcg-q pair */
123 struct request_list rl;
125 /* reference count */
128 /* is this blkg online? protected by both blkcg and q locks */
131 struct blkg_rwstat stat_bytes;
132 struct blkg_rwstat stat_ios;
134 struct blkg_policy_data *pd[BLKCG_MAX_POLS];
136 struct rcu_head rcu_head;
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);
150 struct blkcg_policy {
152 /* cgroup files for the policy */
153 struct cftype *dfl_cftypes;
154 struct cftype *legacy_cftypes;
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;
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;
170 extern struct blkcg blkcg_root;
171 extern struct cgroup_subsys_state * const blkcg_root_css;
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);
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);
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,
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,
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);
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);
211 struct blkg_conf_ctx {
212 struct gendisk *disk;
213 struct blkcg_gq *blkg;
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);
222 static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
224 return css ? container_of(css, struct blkcg, css) : NULL;
227 static inline struct blkcg *task_blkcg(struct task_struct *tsk)
229 return css_to_blkcg(task_css(tsk, io_cgrp_id));
232 static inline struct blkcg *bio_blkcg(struct bio *bio)
234 if (bio && bio->bi_css)
235 return css_to_blkcg(bio->bi_css);
236 return task_blkcg(current);
239 static inline struct cgroup_subsys_state *
240 task_get_blkcg_css(struct task_struct *task)
242 return task_get_css(task, io_cgrp_id);
246 * blkcg_parent - get the parent of a blkcg
247 * @blkcg: blkcg of interest
249 * Return the parent blkcg of @blkcg. Can be called anytime.
251 static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
253 return css_to_blkcg(blkcg->css.parent);
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
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.
267 static inline struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
268 struct request_queue *q,
271 struct blkcg_gq *blkg;
273 if (blkcg == &blkcg_root)
276 blkg = rcu_dereference(blkcg->blkg_hint);
277 if (blkg && blkg->q == q)
280 return blkg_lookup_slowpath(blkcg, q, update_hint);
284 * blkg_lookup - lookup blkg for the specified blkcg - q pair
285 * @blkcg: blkcg of interest
286 * @q: request_queue of interest
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.
292 static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
293 struct request_queue *q)
295 WARN_ON_ONCE(!rcu_read_lock_held());
297 if (unlikely(blk_queue_bypass(q)))
299 return __blkg_lookup(blkcg, q, false);
303 * blkg_to_pdata - get policy private data
304 * @blkg: blkg of interest
305 * @pol: policy of interest
307 * Return pointer to private data associated with the @blkg-@pol pair.
309 static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
310 struct blkcg_policy *pol)
312 return blkg ? blkg->pd[pol->plid] : NULL;
315 static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg,
316 struct blkcg_policy *pol)
318 return blkcg ? blkcg->cpd[pol->plid] : NULL;
322 * pdata_to_blkg - get blkg associated with policy private data
323 * @pd: policy private data of interest
325 * @pd is policy private data. Determine the blkg it's associated with.
327 static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
329 return pd ? pd->blkg : NULL;
332 static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd)
334 return cpd ? cpd->blkcg : NULL;
338 * blkg_path - format cgroup path of blkg
339 * @blkg: blkg of interest
340 * @buf: target buffer
341 * @buflen: target buffer length
343 * Format the path of the cgroup of @blkg into @buf.
345 static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
347 return cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
351 * blkg_get - get a blkg reference
354 * The caller should be holding an existing reference.
356 static inline void blkg_get(struct blkcg_gq *blkg)
358 WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
359 atomic_inc(&blkg->refcnt);
362 void __blkg_release_rcu(struct rcu_head *rcu);
365 * blkg_put - put a blkg reference
368 static inline void blkg_put(struct blkcg_gq *blkg)
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);
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
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.
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)))
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
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.
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)))
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)
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
417 static inline struct request_list *blk_get_rl(struct request_queue *q,
421 struct blkcg_gq *blkg;
425 blkcg = bio_blkcg(bio);
427 /* bypass blkg lookup and use @q->root_rl directly for root */
428 if (blkcg == &blkcg_root)
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.
436 blkg = blkg_lookup(blkcg, q);
449 * blk_put_rl - put request_list
450 * @rl: request_list to put
452 * Put the reference acquired by blk_get_rl(). Should be called under
455 static inline void blk_put_rl(struct request_list *rl)
457 if (rl->blkg->blkcg != &blkcg_root)
462 * blk_rq_set_rl - associate a request with a request_list
463 * @rq: request of interest
464 * @rl: target request_list
466 * Associate @rq with @rl so that accounting and freeing can know the
467 * request_list @rq came from.
469 static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
475 * blk_rq_rl - return the request_list a request came from
476 * @rq: request of interest
478 * Return the request_list @rq is allocated from.
480 static inline struct request_list *blk_rq_rl(struct request *rq)
485 struct request_list *__blk_queue_next_rl(struct request_list *rl,
486 struct request_queue *q);
488 * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
490 * Should be used under queue_lock.
492 #define blk_queue_for_each_rl(rl, q) \
493 for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
495 static inline int blkg_stat_init(struct blkg_stat *stat, gfp_t gfp)
499 ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp);
503 atomic64_set(&stat->aux_cnt, 0);
507 static inline void blkg_stat_exit(struct blkg_stat *stat)
509 percpu_counter_destroy(&stat->cpu_cnt);
513 * blkg_stat_add - add a value to a blkg_stat
514 * @stat: target blkg_stat
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.
520 static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
522 percpu_counter_add_batch(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
526 * blkg_stat_read - read the current value of a blkg_stat
527 * @stat: blkg_stat to read
529 static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
531 return percpu_counter_sum_positive(&stat->cpu_cnt);
535 * blkg_stat_reset - reset a blkg_stat
536 * @stat: blkg_stat to reset
538 static inline void blkg_stat_reset(struct blkg_stat *stat)
540 percpu_counter_set(&stat->cpu_cnt, 0);
541 atomic64_set(&stat->aux_cnt, 0);
545 * blkg_stat_add_aux - add a blkg_stat into another's aux count
546 * @to: the destination blkg_stat
549 * Add @from's count including the aux one to @to's aux count.
551 static inline void blkg_stat_add_aux(struct blkg_stat *to,
552 struct blkg_stat *from)
554 atomic64_add(blkg_stat_read(from) + atomic64_read(&from->aux_cnt),
558 static inline int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
562 for (i = 0; i < BLKG_RWSTAT_NR; i++) {
563 ret = percpu_counter_init(&rwstat->cpu_cnt[i], 0, gfp);
566 percpu_counter_destroy(&rwstat->cpu_cnt[i]);
569 atomic64_set(&rwstat->aux_cnt[i], 0);
574 static inline void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
578 for (i = 0; i < BLKG_RWSTAT_NR; i++)
579 percpu_counter_destroy(&rwstat->cpu_cnt[i]);
583 * blkg_rwstat_add - add a value to a blkg_rwstat
584 * @rwstat: target blkg_rwstat
585 * @op: REQ_OP and flags
588 * Add @val to @rwstat. The counters are chosen according to @rw. The
589 * caller is responsible for synchronizing calls to this function.
591 static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
592 unsigned int op, uint64_t val)
594 struct percpu_counter *cnt;
597 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE];
599 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ];
601 percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH);
604 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC];
606 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC];
608 percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH);
612 * blkg_rwstat_read - read the current values of a blkg_rwstat
613 * @rwstat: blkg_rwstat to read
615 * Read the current snapshot of @rwstat and return it in the aux counts.
617 static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
619 struct blkg_rwstat result;
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]));
629 * blkg_rwstat_total - read the total count of a blkg_rwstat
630 * @rwstat: blkg_rwstat to read
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
636 static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
638 struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
640 return atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
641 atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
645 * blkg_rwstat_reset - reset a blkg_rwstat
646 * @rwstat: blkg_rwstat to reset
648 static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
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);
659 * blkg_rwstat_add_aux - add a blkg_rwstat into another's aux count
660 * @to: the destination blkg_rwstat
663 * Add @from's count including the aux one to @to's aux count.
665 static inline void blkg_rwstat_add_aux(struct blkg_rwstat *to,
666 struct blkg_rwstat *from)
668 struct blkg_rwstat v = blkg_rwstat_read(from);
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]),
677 #ifdef CONFIG_BLK_DEV_THROTTLING
678 extern bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
681 static inline bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
682 struct bio *bio) { return false; }
685 static inline bool blkcg_bio_issue_check(struct request_queue *q,
689 struct blkcg_gq *blkg;
693 blkcg = bio_blkcg(bio);
695 /* associate blkcg if bio hasn't attached one */
696 bio_associate_blkcg(bio, &blkcg->css);
698 blkg = blkg_lookup(blkcg, q);
699 if (unlikely(!blkg)) {
700 spin_lock_irq(q->queue_lock);
701 blkg = blkg_lookup_create(blkcg, q);
704 spin_unlock_irq(q->queue_lock);
707 throtl = blk_throtl_bio(q, blkg, bio);
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);
720 #else /* CONFIG_BLK_CGROUP */
725 struct blkg_policy_data {
728 struct blkcg_policy_data {
734 struct blkcg_policy {
737 #define blkcg_root_css ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))
739 static inline struct cgroup_subsys_state *
740 task_get_blkcg_css(struct task_struct *task)
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) { }
758 static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
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) { }
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; }
773 static inline bool blkcg_bio_issue_check(struct request_queue *q,
774 struct bio *bio) { return true; }
776 #define blk_queue_for_each_rl(rl, q) \
777 for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
779 #endif /* CONFIG_BLOCK */
780 #endif /* CONFIG_BLK_CGROUP */
781 #endif /* _BLK_CGROUP_H */