Re: [PATCH block/for-next 1/4] blkcg: move block/blk-cgroup.h to include/linux/blk-cgroup.h
From: Vivek Goyal
Date: Thu Nov 20 2014 - 15:11:01 EST
On Mon, Nov 17, 2014 at 04:13:21PM -0500, Tejun Heo wrote:
> cgroup aware writeback support will require exposing some of blkcg
> details. In preprataion, move block/blk-cgroup.h to
> include/linux/blk-cgroup.h. This patch is pure file move.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Acked-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Thanks
Vivek
> ---
> Hello, Jens.
>
> These four are misc prep patches on blkcg for cgroup writeback
> support.
>
> Thanks.
>
> block/blk-cgroup.c | 2
> block/blk-cgroup.h | 603 ---------------------------------------------
> block/blk-core.c | 2
> block/blk-sysfs.c | 2
> block/blk-throttle.c | 2
> block/cfq-iosched.c | 2
> block/elevator.c | 2
> include/linux/blk-cgroup.h | 603 +++++++++++++++++++++++++++++++++++++++++++++
> 8 files changed, 609 insertions(+), 609 deletions(-)
>
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -19,7 +19,7 @@
> #include <linux/genhd.h>
> #include <linux/delay.h>
> #include <linux/atomic.h>
> -#include "blk-cgroup.h"
> +#include <linux/blk-cgroup.h>
> #include "blk.h"
>
> #define MAX_KEY_LEN 100
> --- a/block/blk-cgroup.h
> +++ /dev/null
> @@ -1,603 +0,0 @@
> -#ifndef _BLK_CGROUP_H
> -#define _BLK_CGROUP_H
> -/*
> - * Common Block IO controller cgroup interface
> - *
> - * Based on ideas and code from CFQ, CFS and BFQ:
> - * Copyright (C) 2003 Jens Axboe <axboe@xxxxxxxxx>
> - *
> - * Copyright (C) 2008 Fabio Checconi <fabio@xxxxxxxxxxxxxxxx>
> - * Paolo Valente <paolo.valente@xxxxxxxxxx>
> - *
> - * Copyright (C) 2009 Vivek Goyal <vgoyal@xxxxxxxxxx>
> - * Nauman Rafique <nauman@xxxxxxxxxx>
> - */
> -
> -#include <linux/cgroup.h>
> -#include <linux/u64_stats_sync.h>
> -#include <linux/seq_file.h>
> -#include <linux/radix-tree.h>
> -#include <linux/blkdev.h>
> -#include <linux/atomic.h>
> -
> -/* Max limits for throttle policy */
> -#define THROTL_IOPS_MAX UINT_MAX
> -
> -/* CFQ specific, out here for blkcg->cfq_weight */
> -#define CFQ_WEIGHT_MIN 10
> -#define CFQ_WEIGHT_MAX 1000
> -#define CFQ_WEIGHT_DEFAULT 500
> -
> -#ifdef CONFIG_BLK_CGROUP
> -
> -enum blkg_rwstat_type {
> - BLKG_RWSTAT_READ,
> - BLKG_RWSTAT_WRITE,
> - BLKG_RWSTAT_SYNC,
> - BLKG_RWSTAT_ASYNC,
> -
> - BLKG_RWSTAT_NR,
> - BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
> -};
> -
> -struct blkcg_gq;
> -
> -struct blkcg {
> - struct cgroup_subsys_state css;
> - spinlock_t lock;
> -
> - struct radix_tree_root blkg_tree;
> - struct blkcg_gq *blkg_hint;
> - struct hlist_head blkg_list;
> -
> - /* TODO: per-policy storage in blkcg */
> - unsigned int cfq_weight; /* belongs to cfq */
> - unsigned int cfq_leaf_weight;
> -};
> -
> -struct blkg_stat {
> - struct u64_stats_sync syncp;
> - uint64_t cnt;
> -};
> -
> -struct blkg_rwstat {
> - struct u64_stats_sync syncp;
> - uint64_t cnt[BLKG_RWSTAT_NR];
> -};
> -
> -/*
> - * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
> - * request_queue (q). This is used by blkcg policies which need to track
> - * information per blkcg - q pair.
> - *
> - * There can be multiple active blkcg policies and each has its private
> - * data on each blkg, the size of which is determined by
> - * blkcg_policy->pd_size. blkcg core allocates and frees such areas
> - * together with blkg and invokes pd_init/exit_fn() methods.
> - *
> - * Such private data must embed struct blkg_policy_data (pd) at the
> - * beginning and pd_size can't be smaller than pd.
> - */
> -struct blkg_policy_data {
> - /* the blkg and policy id this per-policy data belongs to */
> - struct blkcg_gq *blkg;
> - int plid;
> -
> - /* used during policy activation */
> - struct list_head alloc_node;
> -};
> -
> -/* association between a blk cgroup and a request queue */
> -struct blkcg_gq {
> - /* Pointer to the associated request_queue */
> - struct request_queue *q;
> - struct list_head q_node;
> - struct hlist_node blkcg_node;
> - struct blkcg *blkcg;
> -
> - /* all non-root blkcg_gq's are guaranteed to have access to parent */
> - struct blkcg_gq *parent;
> -
> - /* request allocation list for this blkcg-q pair */
> - struct request_list rl;
> -
> - /* reference count */
> - atomic_t refcnt;
> -
> - /* is this blkg online? protected by both blkcg and q locks */
> - bool online;
> -
> - struct blkg_policy_data *pd[BLKCG_MAX_POLS];
> -
> - struct rcu_head rcu_head;
> -};
> -
> -typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
> -typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg);
> -typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg);
> -typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
> -typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
> -
> -struct blkcg_policy {
> - int plid;
> - /* policy specific private data size */
> - size_t pd_size;
> - /* cgroup files for the policy */
> - struct cftype *cftypes;
> -
> - /* operations */
> - blkcg_pol_init_pd_fn *pd_init_fn;
> - blkcg_pol_online_pd_fn *pd_online_fn;
> - blkcg_pol_offline_pd_fn *pd_offline_fn;
> - blkcg_pol_exit_pd_fn *pd_exit_fn;
> - blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
> -};
> -
> -extern struct blkcg blkcg_root;
> -
> -struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
> -struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
> - struct request_queue *q);
> -int blkcg_init_queue(struct request_queue *q);
> -void blkcg_drain_queue(struct request_queue *q);
> -void blkcg_exit_queue(struct request_queue *q);
> -
> -/* Blkio controller policy registration */
> -int blkcg_policy_register(struct blkcg_policy *pol);
> -void blkcg_policy_unregister(struct blkcg_policy *pol);
> -int blkcg_activate_policy(struct request_queue *q,
> - const struct blkcg_policy *pol);
> -void blkcg_deactivate_policy(struct request_queue *q,
> - const struct blkcg_policy *pol);
> -
> -void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
> - u64 (*prfill)(struct seq_file *,
> - struct blkg_policy_data *, int),
> - const struct blkcg_policy *pol, int data,
> - bool show_total);
> -u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
> -u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
> - const struct blkg_rwstat *rwstat);
> -u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
> -u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
> - int off);
> -
> -u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off);
> -struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
> - int off);
> -
> -struct blkg_conf_ctx {
> - struct gendisk *disk;
> - struct blkcg_gq *blkg;
> - u64 v;
> -};
> -
> -int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
> - const char *input, struct blkg_conf_ctx *ctx);
> -void blkg_conf_finish(struct blkg_conf_ctx *ctx);
> -
> -
> -static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
> -{
> - return css ? container_of(css, struct blkcg, css) : NULL;
> -}
> -
> -static inline struct blkcg *task_blkcg(struct task_struct *tsk)
> -{
> - return css_to_blkcg(task_css(tsk, blkio_cgrp_id));
> -}
> -
> -static inline struct blkcg *bio_blkcg(struct bio *bio)
> -{
> - if (bio && bio->bi_css)
> - return css_to_blkcg(bio->bi_css);
> - return task_blkcg(current);
> -}
> -
> -/**
> - * blkcg_parent - get the parent of a blkcg
> - * @blkcg: blkcg of interest
> - *
> - * Return the parent blkcg of @blkcg. Can be called anytime.
> - */
> -static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
> -{
> - return css_to_blkcg(blkcg->css.parent);
> -}
> -
> -/**
> - * blkg_to_pdata - get policy private data
> - * @blkg: blkg of interest
> - * @pol: policy of interest
> - *
> - * Return pointer to private data associated with the @blkg-@pol pair.
> - */
> -static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
> - struct blkcg_policy *pol)
> -{
> - return blkg ? blkg->pd[pol->plid] : NULL;
> -}
> -
> -/**
> - * pdata_to_blkg - get blkg associated with policy private data
> - * @pd: policy private data of interest
> - *
> - * @pd is policy private data. Determine the blkg it's associated with.
> - */
> -static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
> -{
> - return pd ? pd->blkg : NULL;
> -}
> -
> -/**
> - * blkg_path - format cgroup path of blkg
> - * @blkg: blkg of interest
> - * @buf: target buffer
> - * @buflen: target buffer length
> - *
> - * Format the path of the cgroup of @blkg into @buf.
> - */
> -static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
> -{
> - char *p;
> -
> - p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
> - if (!p) {
> - strncpy(buf, "<unavailable>", buflen);
> - return -ENAMETOOLONG;
> - }
> -
> - memmove(buf, p, buf + buflen - p);
> - return 0;
> -}
> -
> -/**
> - * blkg_get - get a blkg reference
> - * @blkg: blkg to get
> - *
> - * The caller should be holding an existing reference.
> - */
> -static inline void blkg_get(struct blkcg_gq *blkg)
> -{
> - WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
> - atomic_inc(&blkg->refcnt);
> -}
> -
> -void __blkg_release_rcu(struct rcu_head *rcu);
> -
> -/**
> - * blkg_put - put a blkg reference
> - * @blkg: blkg to put
> - */
> -static inline void blkg_put(struct blkcg_gq *blkg)
> -{
> - WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
> - if (atomic_dec_and_test(&blkg->refcnt))
> - call_rcu(&blkg->rcu_head, __blkg_release_rcu);
> -}
> -
> -struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q,
> - bool update_hint);
> -
> -/**
> - * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
> - * @d_blkg: loop cursor pointing to the current descendant
> - * @pos_css: used for iteration
> - * @p_blkg: target blkg to walk descendants of
> - *
> - * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
> - * read locked. If called under either blkcg or queue lock, the iteration
> - * is guaranteed to include all and only online blkgs. The caller may
> - * update @pos_css by calling css_rightmost_descendant() to skip subtree.
> - * @p_blkg is included in the iteration and the first node to be visited.
> - */
> -#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \
> - css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \
> - if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
> - (p_blkg)->q, false)))
> -
> -/**
> - * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
> - * @d_blkg: loop cursor pointing to the current descendant
> - * @pos_css: used for iteration
> - * @p_blkg: target blkg to walk descendants of
> - *
> - * Similar to blkg_for_each_descendant_pre() but performs post-order
> - * traversal instead. Synchronization rules are the same. @p_blkg is
> - * included in the iteration and the last node to be visited.
> - */
> -#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \
> - css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \
> - if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
> - (p_blkg)->q, false)))
> -
> -/**
> - * blk_get_rl - get request_list to use
> - * @q: request_queue of interest
> - * @bio: bio which will be attached to the allocated request (may be %NULL)
> - *
> - * The caller wants to allocate a request from @q to use for @bio. Find
> - * the request_list to use and obtain a reference on it. Should be called
> - * under queue_lock. This function is guaranteed to return non-%NULL
> - * request_list.
> - */
> -static inline struct request_list *blk_get_rl(struct request_queue *q,
> - struct bio *bio)
> -{
> - struct blkcg *blkcg;
> - struct blkcg_gq *blkg;
> -
> - rcu_read_lock();
> -
> - blkcg = bio_blkcg(bio);
> -
> - /* bypass blkg lookup and use @q->root_rl directly for root */
> - if (blkcg == &blkcg_root)
> - goto root_rl;
> -
> - /*
> - * Try to use blkg->rl. blkg lookup may fail under memory pressure
> - * or if either the blkcg or queue is going away. Fall back to
> - * root_rl in such cases.
> - */
> - blkg = blkg_lookup_create(blkcg, q);
> - if (unlikely(IS_ERR(blkg)))
> - goto root_rl;
> -
> - blkg_get(blkg);
> - rcu_read_unlock();
> - return &blkg->rl;
> -root_rl:
> - rcu_read_unlock();
> - return &q->root_rl;
> -}
> -
> -/**
> - * blk_put_rl - put request_list
> - * @rl: request_list to put
> - *
> - * Put the reference acquired by blk_get_rl(). Should be called under
> - * queue_lock.
> - */
> -static inline void blk_put_rl(struct request_list *rl)
> -{
> - /* root_rl may not have blkg set */
> - if (rl->blkg && rl->blkg->blkcg != &blkcg_root)
> - blkg_put(rl->blkg);
> -}
> -
> -/**
> - * blk_rq_set_rl - associate a request with a request_list
> - * @rq: request of interest
> - * @rl: target request_list
> - *
> - * Associate @rq with @rl so that accounting and freeing can know the
> - * request_list @rq came from.
> - */
> -static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
> -{
> - rq->rl = rl;
> -}
> -
> -/**
> - * blk_rq_rl - return the request_list a request came from
> - * @rq: request of interest
> - *
> - * Return the request_list @rq is allocated from.
> - */
> -static inline struct request_list *blk_rq_rl(struct request *rq)
> -{
> - return rq->rl;
> -}
> -
> -struct request_list *__blk_queue_next_rl(struct request_list *rl,
> - struct request_queue *q);
> -/**
> - * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
> - *
> - * Should be used under queue_lock.
> - */
> -#define blk_queue_for_each_rl(rl, q) \
> - for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
> -
> -static inline void blkg_stat_init(struct blkg_stat *stat)
> -{
> - u64_stats_init(&stat->syncp);
> -}
> -
> -/**
> - * blkg_stat_add - add a value to a blkg_stat
> - * @stat: target blkg_stat
> - * @val: value to add
> - *
> - * Add @val to @stat. The caller is responsible for synchronizing calls to
> - * this function.
> - */
> -static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
> -{
> - u64_stats_update_begin(&stat->syncp);
> - stat->cnt += val;
> - u64_stats_update_end(&stat->syncp);
> -}
> -
> -/**
> - * blkg_stat_read - read the current value of a blkg_stat
> - * @stat: blkg_stat to read
> - *
> - * Read the current value of @stat. This function can be called without
> - * synchroniztion and takes care of u64 atomicity.
> - */
> -static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
> -{
> - unsigned int start;
> - uint64_t v;
> -
> - do {
> - start = u64_stats_fetch_begin_irq(&stat->syncp);
> - v = stat->cnt;
> - } while (u64_stats_fetch_retry_irq(&stat->syncp, start));
> -
> - return v;
> -}
> -
> -/**
> - * blkg_stat_reset - reset a blkg_stat
> - * @stat: blkg_stat to reset
> - */
> -static inline void blkg_stat_reset(struct blkg_stat *stat)
> -{
> - stat->cnt = 0;
> -}
> -
> -/**
> - * blkg_stat_merge - merge a blkg_stat into another
> - * @to: the destination blkg_stat
> - * @from: the source
> - *
> - * Add @from's count to @to.
> - */
> -static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from)
> -{
> - blkg_stat_add(to, blkg_stat_read(from));
> -}
> -
> -static inline void blkg_rwstat_init(struct blkg_rwstat *rwstat)
> -{
> - u64_stats_init(&rwstat->syncp);
> -}
> -
> -/**
> - * blkg_rwstat_add - add a value to a blkg_rwstat
> - * @rwstat: target blkg_rwstat
> - * @rw: mask of REQ_{WRITE|SYNC}
> - * @val: value to add
> - *
> - * Add @val to @rwstat. The counters are chosen according to @rw. The
> - * caller is responsible for synchronizing calls to this function.
> - */
> -static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
> - int rw, uint64_t val)
> -{
> - u64_stats_update_begin(&rwstat->syncp);
> -
> - if (rw & REQ_WRITE)
> - rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
> - else
> - rwstat->cnt[BLKG_RWSTAT_READ] += val;
> - if (rw & REQ_SYNC)
> - rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
> - else
> - rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
> -
> - u64_stats_update_end(&rwstat->syncp);
> -}
> -
> -/**
> - * blkg_rwstat_read - read the current values of a blkg_rwstat
> - * @rwstat: blkg_rwstat to read
> - *
> - * Read the current snapshot of @rwstat and return it as the return value.
> - * This function can be called without synchronization and takes care of
> - * u64 atomicity.
> - */
> -static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
> -{
> - unsigned int start;
> - struct blkg_rwstat tmp;
> -
> - do {
> - start = u64_stats_fetch_begin_irq(&rwstat->syncp);
> - tmp = *rwstat;
> - } while (u64_stats_fetch_retry_irq(&rwstat->syncp, start));
> -
> - return tmp;
> -}
> -
> -/**
> - * blkg_rwstat_total - read the total count of a blkg_rwstat
> - * @rwstat: blkg_rwstat to read
> - *
> - * Return the total count of @rwstat regardless of the IO direction. This
> - * function can be called without synchronization and takes care of u64
> - * atomicity.
> - */
> -static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
> -{
> - struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
> -
> - return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
> -}
> -
> -/**
> - * blkg_rwstat_reset - reset a blkg_rwstat
> - * @rwstat: blkg_rwstat to reset
> - */
> -static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
> -{
> - memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
> -}
> -
> -/**
> - * blkg_rwstat_merge - merge a blkg_rwstat into another
> - * @to: the destination blkg_rwstat
> - * @from: the source
> - *
> - * Add @from's counts to @to.
> - */
> -static inline void blkg_rwstat_merge(struct blkg_rwstat *to,
> - struct blkg_rwstat *from)
> -{
> - struct blkg_rwstat v = blkg_rwstat_read(from);
> - int i;
> -
> - u64_stats_update_begin(&to->syncp);
> - for (i = 0; i < BLKG_RWSTAT_NR; i++)
> - to->cnt[i] += v.cnt[i];
> - u64_stats_update_end(&to->syncp);
> -}
> -
> -#else /* CONFIG_BLK_CGROUP */
> -
> -struct cgroup;
> -struct blkcg;
> -
> -struct blkg_policy_data {
> -};
> -
> -struct blkcg_gq {
> -};
> -
> -struct blkcg_policy {
> -};
> -
> -static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
> -static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
> -static inline void blkcg_drain_queue(struct request_queue *q) { }
> -static inline void blkcg_exit_queue(struct request_queue *q) { }
> -static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
> -static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
> -static inline int blkcg_activate_policy(struct request_queue *q,
> - const struct blkcg_policy *pol) { return 0; }
> -static inline void blkcg_deactivate_policy(struct request_queue *q,
> - const struct blkcg_policy *pol) { }
> -
> -static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
> -
> -static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
> - struct blkcg_policy *pol) { return NULL; }
> -static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
> -static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
> -static inline void blkg_get(struct blkcg_gq *blkg) { }
> -static inline void blkg_put(struct blkcg_gq *blkg) { }
> -
> -static inline struct request_list *blk_get_rl(struct request_queue *q,
> - struct bio *bio) { return &q->root_rl; }
> -static inline void blk_put_rl(struct request_list *rl) { }
> -static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
> -static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
> -
> -#define blk_queue_for_each_rl(rl, q) \
> - for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
> -
> -#endif /* CONFIG_BLK_CGROUP */
> -#endif /* _BLK_CGROUP_H */
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -32,12 +32,12 @@
> #include <linux/delay.h>
> #include <linux/ratelimit.h>
> #include <linux/pm_runtime.h>
> +#include <linux/blk-cgroup.h>
>
> #define CREATE_TRACE_POINTS
> #include <trace/events/block.h>
>
> #include "blk.h"
> -#include "blk-cgroup.h"
> #include "blk-mq.h"
>
> EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
> --- a/block/blk-sysfs.c
> +++ b/block/blk-sysfs.c
> @@ -8,9 +8,9 @@
> #include <linux/blkdev.h>
> #include <linux/blktrace_api.h>
> #include <linux/blk-mq.h>
> +#include <linux/blk-cgroup.h>
>
> #include "blk.h"
> -#include "blk-cgroup.h"
> #include "blk-mq.h"
>
> struct queue_sysfs_entry {
> --- a/block/blk-throttle.c
> +++ b/block/blk-throttle.c
> @@ -9,7 +9,7 @@
> #include <linux/blkdev.h>
> #include <linux/bio.h>
> #include <linux/blktrace_api.h>
> -#include "blk-cgroup.h"
> +#include <linux/blk-cgroup.h>
> #include "blk.h"
>
> /* Max dispatch from a group in 1 round */
> --- a/block/cfq-iosched.c
> +++ b/block/cfq-iosched.c
> @@ -14,8 +14,8 @@
> #include <linux/rbtree.h>
> #include <linux/ioprio.h>
> #include <linux/blktrace_api.h>
> +#include <linux/blk-cgroup.h>
> #include "blk.h"
> -#include "blk-cgroup.h"
>
> /*
> * tunables
> --- a/block/elevator.c
> +++ b/block/elevator.c
> @@ -35,11 +35,11 @@
> #include <linux/hash.h>
> #include <linux/uaccess.h>
> #include <linux/pm_runtime.h>
> +#include <linux/blk-cgroup.h>
>
> #include <trace/events/block.h>
>
> #include "blk.h"
> -#include "blk-cgroup.h"
>
> static DEFINE_SPINLOCK(elv_list_lock);
> static LIST_HEAD(elv_list);
> --- /dev/null
> +++ b/include/linux/blk-cgroup.h
> @@ -0,0 +1,603 @@
> +#ifndef _BLK_CGROUP_H
> +#define _BLK_CGROUP_H
> +/*
> + * Common Block IO controller cgroup interface
> + *
> + * Based on ideas and code from CFQ, CFS and BFQ:
> + * Copyright (C) 2003 Jens Axboe <axboe@xxxxxxxxx>
> + *
> + * Copyright (C) 2008 Fabio Checconi <fabio@xxxxxxxxxxxxxxxx>
> + * Paolo Valente <paolo.valente@xxxxxxxxxx>
> + *
> + * Copyright (C) 2009 Vivek Goyal <vgoyal@xxxxxxxxxx>
> + * Nauman Rafique <nauman@xxxxxxxxxx>
> + */
> +
> +#include <linux/cgroup.h>
> +#include <linux/u64_stats_sync.h>
> +#include <linux/seq_file.h>
> +#include <linux/radix-tree.h>
> +#include <linux/blkdev.h>
> +#include <linux/atomic.h>
> +
> +/* Max limits for throttle policy */
> +#define THROTL_IOPS_MAX UINT_MAX
> +
> +/* CFQ specific, out here for blkcg->cfq_weight */
> +#define CFQ_WEIGHT_MIN 10
> +#define CFQ_WEIGHT_MAX 1000
> +#define CFQ_WEIGHT_DEFAULT 500
> +
> +#ifdef CONFIG_BLK_CGROUP
> +
> +enum blkg_rwstat_type {
> + BLKG_RWSTAT_READ,
> + BLKG_RWSTAT_WRITE,
> + BLKG_RWSTAT_SYNC,
> + BLKG_RWSTAT_ASYNC,
> +
> + BLKG_RWSTAT_NR,
> + BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
> +};
> +
> +struct blkcg_gq;
> +
> +struct blkcg {
> + struct cgroup_subsys_state css;
> + spinlock_t lock;
> +
> + struct radix_tree_root blkg_tree;
> + struct blkcg_gq *blkg_hint;
> + struct hlist_head blkg_list;
> +
> + /* TODO: per-policy storage in blkcg */
> + unsigned int cfq_weight; /* belongs to cfq */
> + unsigned int cfq_leaf_weight;
> +};
> +
> +struct blkg_stat {
> + struct u64_stats_sync syncp;
> + uint64_t cnt;
> +};
> +
> +struct blkg_rwstat {
> + struct u64_stats_sync syncp;
> + uint64_t cnt[BLKG_RWSTAT_NR];
> +};
> +
> +/*
> + * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
> + * request_queue (q). This is used by blkcg policies which need to track
> + * information per blkcg - q pair.
> + *
> + * There can be multiple active blkcg policies and each has its private
> + * data on each blkg, the size of which is determined by
> + * blkcg_policy->pd_size. blkcg core allocates and frees such areas
> + * together with blkg and invokes pd_init/exit_fn() methods.
> + *
> + * Such private data must embed struct blkg_policy_data (pd) at the
> + * beginning and pd_size can't be smaller than pd.
> + */
> +struct blkg_policy_data {
> + /* the blkg and policy id this per-policy data belongs to */
> + struct blkcg_gq *blkg;
> + int plid;
> +
> + /* used during policy activation */
> + struct list_head alloc_node;
> +};
> +
> +/* association between a blk cgroup and a request queue */
> +struct blkcg_gq {
> + /* Pointer to the associated request_queue */
> + struct request_queue *q;
> + struct list_head q_node;
> + struct hlist_node blkcg_node;
> + struct blkcg *blkcg;
> +
> + /* all non-root blkcg_gq's are guaranteed to have access to parent */
> + struct blkcg_gq *parent;
> +
> + /* request allocation list for this blkcg-q pair */
> + struct request_list rl;
> +
> + /* reference count */
> + atomic_t refcnt;
> +
> + /* is this blkg online? protected by both blkcg and q locks */
> + bool online;
> +
> + struct blkg_policy_data *pd[BLKCG_MAX_POLS];
> +
> + struct rcu_head rcu_head;
> +};
> +
> +typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
> +typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg);
> +typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg);
> +typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
> +typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
> +
> +struct blkcg_policy {
> + int plid;
> + /* policy specific private data size */
> + size_t pd_size;
> + /* cgroup files for the policy */
> + struct cftype *cftypes;
> +
> + /* operations */
> + blkcg_pol_init_pd_fn *pd_init_fn;
> + blkcg_pol_online_pd_fn *pd_online_fn;
> + blkcg_pol_offline_pd_fn *pd_offline_fn;
> + blkcg_pol_exit_pd_fn *pd_exit_fn;
> + blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
> +};
> +
> +extern struct blkcg blkcg_root;
> +
> +struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
> +struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
> + struct request_queue *q);
> +int blkcg_init_queue(struct request_queue *q);
> +void blkcg_drain_queue(struct request_queue *q);
> +void blkcg_exit_queue(struct request_queue *q);
> +
> +/* Blkio controller policy registration */
> +int blkcg_policy_register(struct blkcg_policy *pol);
> +void blkcg_policy_unregister(struct blkcg_policy *pol);
> +int blkcg_activate_policy(struct request_queue *q,
> + const struct blkcg_policy *pol);
> +void blkcg_deactivate_policy(struct request_queue *q,
> + const struct blkcg_policy *pol);
> +
> +void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
> + u64 (*prfill)(struct seq_file *,
> + struct blkg_policy_data *, int),
> + const struct blkcg_policy *pol, int data,
> + bool show_total);
> +u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
> +u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
> + const struct blkg_rwstat *rwstat);
> +u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
> +u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
> + int off);
> +
> +u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off);
> +struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
> + int off);
> +
> +struct blkg_conf_ctx {
> + struct gendisk *disk;
> + struct blkcg_gq *blkg;
> + u64 v;
> +};
> +
> +int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
> + const char *input, struct blkg_conf_ctx *ctx);
> +void blkg_conf_finish(struct blkg_conf_ctx *ctx);
> +
> +
> +static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
> +{
> + return css ? container_of(css, struct blkcg, css) : NULL;
> +}
> +
> +static inline struct blkcg *task_blkcg(struct task_struct *tsk)
> +{
> + return css_to_blkcg(task_css(tsk, blkio_cgrp_id));
> +}
> +
> +static inline struct blkcg *bio_blkcg(struct bio *bio)
> +{
> + if (bio && bio->bi_css)
> + return css_to_blkcg(bio->bi_css);
> + return task_blkcg(current);
> +}
> +
> +/**
> + * blkcg_parent - get the parent of a blkcg
> + * @blkcg: blkcg of interest
> + *
> + * Return the parent blkcg of @blkcg. Can be called anytime.
> + */
> +static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
> +{
> + return css_to_blkcg(blkcg->css.parent);
> +}
> +
> +/**
> + * blkg_to_pdata - get policy private data
> + * @blkg: blkg of interest
> + * @pol: policy of interest
> + *
> + * Return pointer to private data associated with the @blkg-@pol pair.
> + */
> +static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
> + struct blkcg_policy *pol)
> +{
> + return blkg ? blkg->pd[pol->plid] : NULL;
> +}
> +
> +/**
> + * pdata_to_blkg - get blkg associated with policy private data
> + * @pd: policy private data of interest
> + *
> + * @pd is policy private data. Determine the blkg it's associated with.
> + */
> +static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
> +{
> + return pd ? pd->blkg : NULL;
> +}
> +
> +/**
> + * blkg_path - format cgroup path of blkg
> + * @blkg: blkg of interest
> + * @buf: target buffer
> + * @buflen: target buffer length
> + *
> + * Format the path of the cgroup of @blkg into @buf.
> + */
> +static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
> +{
> + char *p;
> +
> + p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
> + if (!p) {
> + strncpy(buf, "<unavailable>", buflen);
> + return -ENAMETOOLONG;
> + }
> +
> + memmove(buf, p, buf + buflen - p);
> + return 0;
> +}
> +
> +/**
> + * blkg_get - get a blkg reference
> + * @blkg: blkg to get
> + *
> + * The caller should be holding an existing reference.
> + */
> +static inline void blkg_get(struct blkcg_gq *blkg)
> +{
> + WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
> + atomic_inc(&blkg->refcnt);
> +}
> +
> +void __blkg_release_rcu(struct rcu_head *rcu);
> +
> +/**
> + * blkg_put - put a blkg reference
> + * @blkg: blkg to put
> + */
> +static inline void blkg_put(struct blkcg_gq *blkg)
> +{
> + WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
> + if (atomic_dec_and_test(&blkg->refcnt))
> + call_rcu(&blkg->rcu_head, __blkg_release_rcu);
> +}
> +
> +struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q,
> + bool update_hint);
> +
> +/**
> + * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
> + * @d_blkg: loop cursor pointing to the current descendant
> + * @pos_css: used for iteration
> + * @p_blkg: target blkg to walk descendants of
> + *
> + * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
> + * read locked. If called under either blkcg or queue lock, the iteration
> + * is guaranteed to include all and only online blkgs. The caller may
> + * update @pos_css by calling css_rightmost_descendant() to skip subtree.
> + * @p_blkg is included in the iteration and the first node to be visited.
> + */
> +#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \
> + css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \
> + if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
> + (p_blkg)->q, false)))
> +
> +/**
> + * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
> + * @d_blkg: loop cursor pointing to the current descendant
> + * @pos_css: used for iteration
> + * @p_blkg: target blkg to walk descendants of
> + *
> + * Similar to blkg_for_each_descendant_pre() but performs post-order
> + * traversal instead. Synchronization rules are the same. @p_blkg is
> + * included in the iteration and the last node to be visited.
> + */
> +#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \
> + css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \
> + if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
> + (p_blkg)->q, false)))
> +
> +/**
> + * blk_get_rl - get request_list to use
> + * @q: request_queue of interest
> + * @bio: bio which will be attached to the allocated request (may be %NULL)
> + *
> + * The caller wants to allocate a request from @q to use for @bio. Find
> + * the request_list to use and obtain a reference on it. Should be called
> + * under queue_lock. This function is guaranteed to return non-%NULL
> + * request_list.
> + */
> +static inline struct request_list *blk_get_rl(struct request_queue *q,
> + struct bio *bio)
> +{
> + struct blkcg *blkcg;
> + struct blkcg_gq *blkg;
> +
> + rcu_read_lock();
> +
> + blkcg = bio_blkcg(bio);
> +
> + /* bypass blkg lookup and use @q->root_rl directly for root */
> + if (blkcg == &blkcg_root)
> + goto root_rl;
> +
> + /*
> + * Try to use blkg->rl. blkg lookup may fail under memory pressure
> + * or if either the blkcg or queue is going away. Fall back to
> + * root_rl in such cases.
> + */
> + blkg = blkg_lookup_create(blkcg, q);
> + if (unlikely(IS_ERR(blkg)))
> + goto root_rl;
> +
> + blkg_get(blkg);
> + rcu_read_unlock();
> + return &blkg->rl;
> +root_rl:
> + rcu_read_unlock();
> + return &q->root_rl;
> +}
> +
> +/**
> + * blk_put_rl - put request_list
> + * @rl: request_list to put
> + *
> + * Put the reference acquired by blk_get_rl(). Should be called under
> + * queue_lock.
> + */
> +static inline void blk_put_rl(struct request_list *rl)
> +{
> + /* root_rl may not have blkg set */
> + if (rl->blkg && rl->blkg->blkcg != &blkcg_root)
> + blkg_put(rl->blkg);
> +}
> +
> +/**
> + * blk_rq_set_rl - associate a request with a request_list
> + * @rq: request of interest
> + * @rl: target request_list
> + *
> + * Associate @rq with @rl so that accounting and freeing can know the
> + * request_list @rq came from.
> + */
> +static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
> +{
> + rq->rl = rl;
> +}
> +
> +/**
> + * blk_rq_rl - return the request_list a request came from
> + * @rq: request of interest
> + *
> + * Return the request_list @rq is allocated from.
> + */
> +static inline struct request_list *blk_rq_rl(struct request *rq)
> +{
> + return rq->rl;
> +}
> +
> +struct request_list *__blk_queue_next_rl(struct request_list *rl,
> + struct request_queue *q);
> +/**
> + * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
> + *
> + * Should be used under queue_lock.
> + */
> +#define blk_queue_for_each_rl(rl, q) \
> + for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
> +
> +static inline void blkg_stat_init(struct blkg_stat *stat)
> +{
> + u64_stats_init(&stat->syncp);
> +}
> +
> +/**
> + * blkg_stat_add - add a value to a blkg_stat
> + * @stat: target blkg_stat
> + * @val: value to add
> + *
> + * Add @val to @stat. The caller is responsible for synchronizing calls to
> + * this function.
> + */
> +static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
> +{
> + u64_stats_update_begin(&stat->syncp);
> + stat->cnt += val;
> + u64_stats_update_end(&stat->syncp);
> +}
> +
> +/**
> + * blkg_stat_read - read the current value of a blkg_stat
> + * @stat: blkg_stat to read
> + *
> + * Read the current value of @stat. This function can be called without
> + * synchroniztion and takes care of u64 atomicity.
> + */
> +static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
> +{
> + unsigned int start;
> + uint64_t v;
> +
> + do {
> + start = u64_stats_fetch_begin_irq(&stat->syncp);
> + v = stat->cnt;
> + } while (u64_stats_fetch_retry_irq(&stat->syncp, start));
> +
> + return v;
> +}
> +
> +/**
> + * blkg_stat_reset - reset a blkg_stat
> + * @stat: blkg_stat to reset
> + */
> +static inline void blkg_stat_reset(struct blkg_stat *stat)
> +{
> + stat->cnt = 0;
> +}
> +
> +/**
> + * blkg_stat_merge - merge a blkg_stat into another
> + * @to: the destination blkg_stat
> + * @from: the source
> + *
> + * Add @from's count to @to.
> + */
> +static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from)
> +{
> + blkg_stat_add(to, blkg_stat_read(from));
> +}
> +
> +static inline void blkg_rwstat_init(struct blkg_rwstat *rwstat)
> +{
> + u64_stats_init(&rwstat->syncp);
> +}
> +
> +/**
> + * blkg_rwstat_add - add a value to a blkg_rwstat
> + * @rwstat: target blkg_rwstat
> + * @rw: mask of REQ_{WRITE|SYNC}
> + * @val: value to add
> + *
> + * Add @val to @rwstat. The counters are chosen according to @rw. The
> + * caller is responsible for synchronizing calls to this function.
> + */
> +static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
> + int rw, uint64_t val)
> +{
> + u64_stats_update_begin(&rwstat->syncp);
> +
> + if (rw & REQ_WRITE)
> + rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
> + else
> + rwstat->cnt[BLKG_RWSTAT_READ] += val;
> + if (rw & REQ_SYNC)
> + rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
> + else
> + rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
> +
> + u64_stats_update_end(&rwstat->syncp);
> +}
> +
> +/**
> + * blkg_rwstat_read - read the current values of a blkg_rwstat
> + * @rwstat: blkg_rwstat to read
> + *
> + * Read the current snapshot of @rwstat and return it as the return value.
> + * This function can be called without synchronization and takes care of
> + * u64 atomicity.
> + */
> +static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
> +{
> + unsigned int start;
> + struct blkg_rwstat tmp;
> +
> + do {
> + start = u64_stats_fetch_begin_irq(&rwstat->syncp);
> + tmp = *rwstat;
> + } while (u64_stats_fetch_retry_irq(&rwstat->syncp, start));
> +
> + return tmp;
> +}
> +
> +/**
> + * blkg_rwstat_total - read the total count of a blkg_rwstat
> + * @rwstat: blkg_rwstat to read
> + *
> + * Return the total count of @rwstat regardless of the IO direction. This
> + * function can be called without synchronization and takes care of u64
> + * atomicity.
> + */
> +static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
> +{
> + struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
> +
> + return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
> +}
> +
> +/**
> + * blkg_rwstat_reset - reset a blkg_rwstat
> + * @rwstat: blkg_rwstat to reset
> + */
> +static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
> +{
> + memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
> +}
> +
> +/**
> + * blkg_rwstat_merge - merge a blkg_rwstat into another
> + * @to: the destination blkg_rwstat
> + * @from: the source
> + *
> + * Add @from's counts to @to.
> + */
> +static inline void blkg_rwstat_merge(struct blkg_rwstat *to,
> + struct blkg_rwstat *from)
> +{
> + struct blkg_rwstat v = blkg_rwstat_read(from);
> + int i;
> +
> + u64_stats_update_begin(&to->syncp);
> + for (i = 0; i < BLKG_RWSTAT_NR; i++)
> + to->cnt[i] += v.cnt[i];
> + u64_stats_update_end(&to->syncp);
> +}
> +
> +#else /* CONFIG_BLK_CGROUP */
> +
> +struct cgroup;
> +struct blkcg;
> +
> +struct blkg_policy_data {
> +};
> +
> +struct blkcg_gq {
> +};
> +
> +struct blkcg_policy {
> +};
> +
> +static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
> +static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
> +static inline void blkcg_drain_queue(struct request_queue *q) { }
> +static inline void blkcg_exit_queue(struct request_queue *q) { }
> +static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
> +static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
> +static inline int blkcg_activate_policy(struct request_queue *q,
> + const struct blkcg_policy *pol) { return 0; }
> +static inline void blkcg_deactivate_policy(struct request_queue *q,
> + const struct blkcg_policy *pol) { }
> +
> +static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
> +
> +static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
> + struct blkcg_policy *pol) { return NULL; }
> +static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
> +static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
> +static inline void blkg_get(struct blkcg_gq *blkg) { }
> +static inline void blkg_put(struct blkcg_gq *blkg) { }
> +
> +static inline struct request_list *blk_get_rl(struct request_queue *q,
> + struct bio *bio) { return &q->root_rl; }
> +static inline void blk_put_rl(struct request_list *rl) { }
> +static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
> +static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
> +
> +#define blk_queue_for_each_rl(rl, q) \
> + for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
> +
> +#endif /* CONFIG_BLK_CGROUP */
> +#endif /* _BLK_CGROUP_H */
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