4 * Common Block IO controller cgroup interface
6 * Based on ideas and code from CFQ, CFS and BFQ:
7 * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
9 * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
10 * Paolo Valente <paolo.valente@unimore.it>
12 * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
13 * Nauman Rafique <nauman@google.com>
16 #include <linux/cgroup.h>
17 #include <linux/percpu_counter.h>
18 #include <linux/seq_file.h>
19 #include <linux/radix-tree.h>
20 #include <linux/blkdev.h>
21 #include <linux/atomic.h>
23 /* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */
24 #define BLKG_STAT_CPU_BATCH (INT_MAX / 2)
26 /* Max limits for throttle policy */
27 #define THROTL_IOPS_MAX UINT_MAX
29 #ifdef CONFIG_BLK_CGROUP
31 enum blkg_rwstat_type {
38 BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
44 struct cgroup_subsys_state css;
47 struct radix_tree_root blkg_tree;
48 struct blkcg_gq *blkg_hint;
49 struct hlist_head blkg_list;
51 struct blkcg_policy_data *cpd[BLKCG_MAX_POLS];
53 struct list_head all_blkcgs_node;
54 #ifdef CONFIG_CGROUP_WRITEBACK
55 struct list_head cgwb_list;
60 * blkg_[rw]stat->aux_cnt is excluded for local stats but included for
61 * recursive. Used to carry stats of dead children, and, for blkg_rwstat,
62 * to carry result values from read and sum operations.
65 struct percpu_counter cpu_cnt;
70 struct percpu_counter cpu_cnt[BLKG_RWSTAT_NR];
71 atomic64_t aux_cnt[BLKG_RWSTAT_NR];
75 * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
76 * request_queue (q). This is used by blkcg policies which need to track
77 * information per blkcg - q pair.
79 * There can be multiple active blkcg policies and each blkg:policy pair is
80 * represented by a blkg_policy_data which is allocated and freed by each
81 * policy's pd_alloc/free_fn() methods. A policy can allocate private data
82 * area by allocating larger data structure which embeds blkg_policy_data
85 struct blkg_policy_data {
86 /* the blkg and policy id this per-policy data belongs to */
87 struct blkcg_gq *blkg;
92 * Policies that need to keep per-blkcg data which is independent from any
93 * request_queue associated to it should implement cpd_alloc/free_fn()
94 * methods. A policy can allocate private data area by allocating larger
95 * data structure which embeds blkcg_policy_data at the beginning.
96 * cpd_init() is invoked to let each policy handle per-blkcg data.
98 struct blkcg_policy_data {
99 /* the blkcg and policy id this per-policy data belongs to */
104 /* association between a blk cgroup and a request queue */
106 /* Pointer to the associated request_queue */
107 struct request_queue *q;
108 struct list_head q_node;
109 struct hlist_node blkcg_node;
113 * Each blkg gets congested separately and the congestion state is
114 * propagated to the matching bdi_writeback_congested.
116 struct bdi_writeback_congested *wb_congested;
118 /* all non-root blkcg_gq's are guaranteed to have access to parent */
119 struct blkcg_gq *parent;
121 /* request allocation list for this blkcg-q pair */
122 struct request_list rl;
124 /* reference count */
127 /* is this blkg online? protected by both blkcg and q locks */
130 struct blkg_rwstat stat_bytes;
131 struct blkg_rwstat stat_ios;
133 struct blkg_policy_data *pd[BLKCG_MAX_POLS];
135 struct rcu_head rcu_head;
138 typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp);
139 typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd);
140 typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd);
141 typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, int node);
142 typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd);
143 typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);
144 typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd);
145 typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);
146 typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd);
148 struct blkcg_policy {
150 /* cgroup files for the policy */
151 struct cftype *dfl_cftypes;
152 struct cftype *legacy_cftypes;
155 blkcg_pol_alloc_cpd_fn *cpd_alloc_fn;
156 blkcg_pol_init_cpd_fn *cpd_init_fn;
157 blkcg_pol_free_cpd_fn *cpd_free_fn;
159 blkcg_pol_alloc_pd_fn *pd_alloc_fn;
160 blkcg_pol_init_pd_fn *pd_init_fn;
161 blkcg_pol_online_pd_fn *pd_online_fn;
162 blkcg_pol_offline_pd_fn *pd_offline_fn;
163 blkcg_pol_free_pd_fn *pd_free_fn;
164 blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
167 extern struct blkcg blkcg_root;
168 extern struct cgroup_subsys_state * const blkcg_root_css;
170 struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg,
171 struct request_queue *q, bool update_hint);
172 struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
173 struct request_queue *q);
174 int blkcg_init_queue(struct request_queue *q);
175 void blkcg_drain_queue(struct request_queue *q);
176 void blkcg_exit_queue(struct request_queue *q);
178 /* Blkio controller policy registration */
179 int blkcg_policy_register(struct blkcg_policy *pol);
180 void blkcg_policy_unregister(struct blkcg_policy *pol);
181 int blkcg_activate_policy(struct request_queue *q,
182 const struct blkcg_policy *pol);
183 void blkcg_deactivate_policy(struct request_queue *q,
184 const struct blkcg_policy *pol);
186 const char *blkg_dev_name(struct blkcg_gq *blkg);
187 void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
188 u64 (*prfill)(struct seq_file *,
189 struct blkg_policy_data *, int),
190 const struct blkcg_policy *pol, int data,
192 u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
193 u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
194 const struct blkg_rwstat *rwstat);
195 u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
196 u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
198 int blkg_print_stat_bytes(struct seq_file *sf, void *v);
199 int blkg_print_stat_ios(struct seq_file *sf, void *v);
200 int blkg_print_stat_bytes_recursive(struct seq_file *sf, void *v);
201 int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v);
203 u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg,
204 struct blkcg_policy *pol, int off);
205 struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkcg_gq *blkg,
206 struct blkcg_policy *pol, int off);
208 struct blkg_conf_ctx {
209 struct gendisk *disk;
210 struct blkcg_gq *blkg;
214 int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
215 char *input, struct blkg_conf_ctx *ctx);
216 void blkg_conf_finish(struct blkg_conf_ctx *ctx);
219 static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
221 return css ? container_of(css, struct blkcg, css) : NULL;
224 static inline struct blkcg *task_blkcg(struct task_struct *tsk)
226 return css_to_blkcg(task_css(tsk, io_cgrp_id));
229 static inline struct blkcg *bio_blkcg(struct bio *bio)
231 if (bio && bio->bi_css)
232 return css_to_blkcg(bio->bi_css);
233 return task_blkcg(current);
236 static inline struct cgroup_subsys_state *
237 task_get_blkcg_css(struct task_struct *task)
239 return task_get_css(task, io_cgrp_id);
243 * blkcg_parent - get the parent of a blkcg
244 * @blkcg: blkcg of interest
246 * Return the parent blkcg of @blkcg. Can be called anytime.
248 static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
250 return css_to_blkcg(blkcg->css.parent);
254 * __blkg_lookup - internal version of blkg_lookup()
255 * @blkcg: blkcg of interest
256 * @q: request_queue of interest
257 * @update_hint: whether to update lookup hint with the result or not
259 * This is internal version and shouldn't be used by policy
260 * implementations. Looks up blkgs for the @blkcg - @q pair regardless of
261 * @q's bypass state. If @update_hint is %true, the caller should be
262 * holding @q->queue_lock and lookup hint is updated on success.
264 static inline struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
265 struct request_queue *q,
268 struct blkcg_gq *blkg;
270 if (blkcg == &blkcg_root)
273 blkg = rcu_dereference(blkcg->blkg_hint);
274 if (blkg && blkg->q == q)
277 return blkg_lookup_slowpath(blkcg, q, update_hint);
281 * blkg_lookup - lookup blkg for the specified blkcg - q pair
282 * @blkcg: blkcg of interest
283 * @q: request_queue of interest
285 * Lookup blkg for the @blkcg - @q pair. This function should be called
286 * under RCU read lock and is guaranteed to return %NULL if @q is bypassing
287 * - see blk_queue_bypass_start() for details.
289 static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
290 struct request_queue *q)
292 WARN_ON_ONCE(!rcu_read_lock_held());
294 if (unlikely(blk_queue_bypass(q)))
296 return __blkg_lookup(blkcg, q, false);
300 * blkg_to_pdata - get policy private data
301 * @blkg: blkg of interest
302 * @pol: policy of interest
304 * Return pointer to private data associated with the @blkg-@pol pair.
306 static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
307 struct blkcg_policy *pol)
309 return blkg ? blkg->pd[pol->plid] : NULL;
312 static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg,
313 struct blkcg_policy *pol)
315 return blkcg ? blkcg->cpd[pol->plid] : NULL;
319 * pdata_to_blkg - get blkg associated with policy private data
320 * @pd: policy private data of interest
322 * @pd is policy private data. Determine the blkg it's associated with.
324 static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
326 return pd ? pd->blkg : NULL;
329 static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd)
331 return cpd ? cpd->blkcg : NULL;
335 * blkg_path - format cgroup path of blkg
336 * @blkg: blkg of interest
337 * @buf: target buffer
338 * @buflen: target buffer length
340 * Format the path of the cgroup of @blkg into @buf.
342 static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
346 p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
348 strncpy(buf, "<unavailable>", buflen);
349 return -ENAMETOOLONG;
352 memmove(buf, p, buf + buflen - p);
357 * blkg_get - get a blkg reference
360 * The caller should be holding an existing reference.
362 static inline void blkg_get(struct blkcg_gq *blkg)
364 WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
365 atomic_inc(&blkg->refcnt);
368 void __blkg_release_rcu(struct rcu_head *rcu);
371 * blkg_put - put a blkg reference
374 static inline void blkg_put(struct blkcg_gq *blkg)
376 WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
377 if (atomic_dec_and_test(&blkg->refcnt))
378 call_rcu(&blkg->rcu_head, __blkg_release_rcu);
382 * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
383 * @d_blkg: loop cursor pointing to the current descendant
384 * @pos_css: used for iteration
385 * @p_blkg: target blkg to walk descendants of
387 * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
388 * read locked. If called under either blkcg or queue lock, the iteration
389 * is guaranteed to include all and only online blkgs. The caller may
390 * update @pos_css by calling css_rightmost_descendant() to skip subtree.
391 * @p_blkg is included in the iteration and the first node to be visited.
393 #define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \
394 css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \
395 if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
396 (p_blkg)->q, false)))
399 * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
400 * @d_blkg: loop cursor pointing to the current descendant
401 * @pos_css: used for iteration
402 * @p_blkg: target blkg to walk descendants of
404 * Similar to blkg_for_each_descendant_pre() but performs post-order
405 * traversal instead. Synchronization rules are the same. @p_blkg is
406 * included in the iteration and the last node to be visited.
408 #define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \
409 css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \
410 if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
411 (p_blkg)->q, false)))
414 * blk_get_rl - get request_list to use
415 * @q: request_queue of interest
416 * @bio: bio which will be attached to the allocated request (may be %NULL)
418 * The caller wants to allocate a request from @q to use for @bio. Find
419 * the request_list to use and obtain a reference on it. Should be called
420 * under queue_lock. This function is guaranteed to return non-%NULL
423 static inline struct request_list *blk_get_rl(struct request_queue *q,
427 struct blkcg_gq *blkg;
431 blkcg = bio_blkcg(bio);
433 /* bypass blkg lookup and use @q->root_rl directly for root */
434 if (blkcg == &blkcg_root)
438 * Try to use blkg->rl. blkg lookup may fail under memory pressure
439 * or if either the blkcg or queue is going away. Fall back to
440 * root_rl in such cases.
442 blkg = blkg_lookup(blkcg, q);
455 * blk_put_rl - put request_list
456 * @rl: request_list to put
458 * Put the reference acquired by blk_get_rl(). Should be called under
461 static inline void blk_put_rl(struct request_list *rl)
463 if (rl->blkg->blkcg != &blkcg_root)
468 * blk_rq_set_rl - associate a request with a request_list
469 * @rq: request of interest
470 * @rl: target request_list
472 * Associate @rq with @rl so that accounting and freeing can know the
473 * request_list @rq came from.
475 static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
481 * blk_rq_rl - return the request_list a request came from
482 * @rq: request of interest
484 * Return the request_list @rq is allocated from.
486 static inline struct request_list *blk_rq_rl(struct request *rq)
491 struct request_list *__blk_queue_next_rl(struct request_list *rl,
492 struct request_queue *q);
494 * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
496 * Should be used under queue_lock.
498 #define blk_queue_for_each_rl(rl, q) \
499 for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
501 static inline int blkg_stat_init(struct blkg_stat *stat, gfp_t gfp)
505 ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp);
509 atomic64_set(&stat->aux_cnt, 0);
513 static inline void blkg_stat_exit(struct blkg_stat *stat)
515 percpu_counter_destroy(&stat->cpu_cnt);
519 * blkg_stat_add - add a value to a blkg_stat
520 * @stat: target blkg_stat
523 * Add @val to @stat. The caller must ensure that IRQ on the same CPU
524 * don't re-enter this function for the same counter.
526 static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
528 __percpu_counter_add(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
532 * blkg_stat_read - read the current value of a blkg_stat
533 * @stat: blkg_stat to read
535 static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
537 return percpu_counter_sum_positive(&stat->cpu_cnt);
541 * blkg_stat_reset - reset a blkg_stat
542 * @stat: blkg_stat to reset
544 static inline void blkg_stat_reset(struct blkg_stat *stat)
546 percpu_counter_set(&stat->cpu_cnt, 0);
547 atomic64_set(&stat->aux_cnt, 0);
551 * blkg_stat_add_aux - add a blkg_stat into another's aux count
552 * @to: the destination blkg_stat
555 * Add @from's count including the aux one to @to's aux count.
557 static inline void blkg_stat_add_aux(struct blkg_stat *to,
558 struct blkg_stat *from)
560 atomic64_add(blkg_stat_read(from) + atomic64_read(&from->aux_cnt),
564 static inline int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
568 for (i = 0; i < BLKG_RWSTAT_NR; i++) {
569 ret = percpu_counter_init(&rwstat->cpu_cnt[i], 0, gfp);
572 percpu_counter_destroy(&rwstat->cpu_cnt[i]);
575 atomic64_set(&rwstat->aux_cnt[i], 0);
580 static inline void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
584 for (i = 0; i < BLKG_RWSTAT_NR; i++)
585 percpu_counter_destroy(&rwstat->cpu_cnt[i]);
589 * blkg_rwstat_add - add a value to a blkg_rwstat
590 * @rwstat: target blkg_rwstat
591 * @rw: mask of REQ_{WRITE|SYNC}
594 * Add @val to @rwstat. The counters are chosen according to @rw. The
595 * caller is responsible for synchronizing calls to this function.
597 static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
598 int rw, uint64_t val)
600 struct percpu_counter *cnt;
603 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE];
605 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ];
607 __percpu_counter_add(cnt, val, BLKG_STAT_CPU_BATCH);
610 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC];
612 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC];
614 __percpu_counter_add(cnt, val, BLKG_STAT_CPU_BATCH);
618 * blkg_rwstat_read - read the current values of a blkg_rwstat
619 * @rwstat: blkg_rwstat to read
621 * Read the current snapshot of @rwstat and return it in the aux counts.
623 static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
625 struct blkg_rwstat result;
628 for (i = 0; i < BLKG_RWSTAT_NR; i++)
629 atomic64_set(&result.aux_cnt[i],
630 percpu_counter_sum_positive(&rwstat->cpu_cnt[i]));
635 * blkg_rwstat_total - read the total count of a blkg_rwstat
636 * @rwstat: blkg_rwstat to read
638 * Return the total count of @rwstat regardless of the IO direction. This
639 * function can be called without synchronization and takes care of u64
642 static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
644 struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
646 return atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
647 atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
651 * blkg_rwstat_reset - reset a blkg_rwstat
652 * @rwstat: blkg_rwstat to reset
654 static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
658 for (i = 0; i < BLKG_RWSTAT_NR; i++) {
659 percpu_counter_set(&rwstat->cpu_cnt[i], 0);
660 atomic64_set(&rwstat->aux_cnt[i], 0);
665 * blkg_rwstat_add_aux - add a blkg_rwstat into another's aux count
666 * @to: the destination blkg_rwstat
669 * Add @from's count including the aux one to @to's aux count.
671 static inline void blkg_rwstat_add_aux(struct blkg_rwstat *to,
672 struct blkg_rwstat *from)
674 struct blkg_rwstat v = blkg_rwstat_read(from);
677 for (i = 0; i < BLKG_RWSTAT_NR; i++)
678 atomic64_add(atomic64_read(&v.aux_cnt[i]) +
679 atomic64_read(&from->aux_cnt[i]),
683 #ifdef CONFIG_BLK_DEV_THROTTLING
684 extern bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
687 static inline bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
688 struct bio *bio) { return false; }
691 static inline bool blkcg_bio_issue_check(struct request_queue *q,
695 struct blkcg_gq *blkg;
699 blkcg = bio_blkcg(bio);
701 blkg = blkg_lookup(blkcg, q);
702 if (unlikely(!blkg)) {
703 spin_lock_irq(q->queue_lock);
704 blkg = blkg_lookup_create(blkcg, q);
707 spin_unlock_irq(q->queue_lock);
710 throtl = blk_throtl_bio(q, blkg, bio);
713 blkg = blkg ?: q->root_blkg;
714 blkg_rwstat_add(&blkg->stat_bytes, bio->bi_flags,
715 bio->bi_iter.bi_size);
716 blkg_rwstat_add(&blkg->stat_ios, bio->bi_flags, 1);
723 #else /* CONFIG_BLK_CGROUP */
728 struct blkg_policy_data {
731 struct blkcg_policy_data {
737 struct blkcg_policy {
740 #define blkcg_root_css ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))
742 static inline struct cgroup_subsys_state *
743 task_get_blkcg_css(struct task_struct *task)
750 static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
751 static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
752 static inline void blkcg_drain_queue(struct request_queue *q) { }
753 static inline void blkcg_exit_queue(struct request_queue *q) { }
754 static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
755 static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
756 static inline int blkcg_activate_policy(struct request_queue *q,
757 const struct blkcg_policy *pol) { return 0; }
758 static inline void blkcg_deactivate_policy(struct request_queue *q,
759 const struct blkcg_policy *pol) { }
761 static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
763 static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
764 struct blkcg_policy *pol) { return NULL; }
765 static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
766 static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
767 static inline void blkg_get(struct blkcg_gq *blkg) { }
768 static inline void blkg_put(struct blkcg_gq *blkg) { }
770 static inline struct request_list *blk_get_rl(struct request_queue *q,
771 struct bio *bio) { return &q->root_rl; }
772 static inline void blk_put_rl(struct request_list *rl) { }
773 static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
774 static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
776 static inline bool blkcg_bio_issue_check(struct request_queue *q,
777 struct bio *bio) { return true; }
779 #define blk_queue_for_each_rl(rl, q) \
780 for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
782 #endif /* CONFIG_BLOCK */
783 #endif /* CONFIG_BLK_CGROUP */
784 #endif /* _BLK_CGROUP_H */