#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@kernel.dk> * * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it> * Paolo Valente <paolo.valente@unimore.it> * * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com> * Nauman Rafique <nauman@google.com> */ #include <linux/cgroup.h>#include <linux/percpu_counter.h>#include <linux/seq_file.h>#include <linux/radix-tree.h>#include <linux/blkdev.h>#include <linux/atomic.h> /* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */#define BLKG_STAT_CPU_BATCH (INT_MAX / 2) /* Max limits for throttle policy */#define THROTL_IOPS_MAX UINT_MAX #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 __rcu *blkg_hint; struct hlist_head blkg_list; struct blkcg_policy_data *cpd[BLKCG_MAX_POLS]; struct list_head all_blkcgs_node;#ifdef CONFIG_CGROUP_WRITEBACK struct list_head cgwb_list;#endif}; /* * blkg_[rw]stat->aux_cnt is excluded for local stats but included for * recursive. Used to carry stats of dead children, and, for blkg_rwstat, * to carry result values from read and sum operations. */struct blkg_stat { struct percpu_counter cpu_cnt; atomic64_t aux_cnt;}; struct blkg_rwstat { struct percpu_counter cpu_cnt[BLKG_RWSTAT_NR]; atomic64_t aux_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 blkg:policy pair is * represented by a blkg_policy_data which is allocated and freed by each * policy's pd_alloc/free_fn() methods. A policy can allocate private data * area by allocating larger data structure which embeds blkg_policy_data * at the beginning. */struct blkg_policy_data { /* the blkg and policy id this per-policy data belongs to */ struct blkcg_gq *blkg; int plid;}; /* * Policies that need to keep per-blkcg data which is independent from any * request_queue associated to it should implement cpd_alloc/free_fn() * methods. A policy can allocate private data area by allocating larger * data structure which embeds blkcg_policy_data at the beginning. * cpd_init() is invoked to let each policy handle per-blkcg data. */struct blkcg_policy_data { /* the blkcg and policy id this per-policy data belongs to */ struct blkcg *blkcg; int plid;}; /* 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; /* * Each blkg gets congested separately and the congestion state is * propagated to the matching bdi_writeback_congested. */ struct bdi_writeback_congested *wb_congested; /* 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_rwstat stat_bytes; struct blkg_rwstat stat_ios; struct blkg_policy_data *pd[BLKCG_MAX_POLS]; struct rcu_head rcu_head;}; typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp);typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd);typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd);typedef void (blkcg_pol_bind_cpd_fn)(struct blkcg_policy_data *cpd);typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, int node);typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd);typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd);typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd); struct blkcg_policy { int plid; /* cgroup files for the policy */ struct cftype *dfl_cftypes; struct cftype *legacy_cftypes; /* operations */ blkcg_pol_alloc_cpd_fn *cpd_alloc_fn; blkcg_pol_init_cpd_fn *cpd_init_fn; blkcg_pol_free_cpd_fn *cpd_free_fn; blkcg_pol_bind_cpd_fn *cpd_bind_fn; blkcg_pol_alloc_pd_fn *pd_alloc_fn; 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_free_pd_fn *pd_free_fn; blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;}; extern struct blkcg blkcg_root;extern struct cgroup_subsys_state * const blkcg_root_css; struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg, struct request_queue *q, bool update_hint);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); const char *blkg_dev_name(struct blkcg_gq *blkg);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);int blkg_print_stat_bytes(struct seq_file *sf, void *v);int blkg_print_stat_ios(struct seq_file *sf, void *v);int blkg_print_stat_bytes_recursive(struct seq_file *sf, void *v);int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v); u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol, int off);struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol, int off); struct blkg_conf_ctx { struct gendisk *disk; struct blkcg_gq *blkg; char *body;}; int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, 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, io_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);} static inline struct cgroup_subsys_state *task_get_blkcg_css(struct task_struct *task){ return task_get_css(task, io_cgrp_id);} /** * 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_lookup - internal version of blkg_lookup() * @blkcg: blkcg of interest * @q: request_queue of interest * @update_hint: whether to update lookup hint with the result or not * * This is internal version and shouldn't be used by policy * implementations. Looks up blkgs for the @blkcg - @q pair regardless of * @q's bypass state. If @update_hint is %true, the caller should be * holding @q->queue_lock and lookup hint is updated on success. */static inline struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q, bool update_hint){ struct blkcg_gq *blkg; if (blkcg == &blkcg_root) return q->root_blkg; blkg = rcu_dereference(blkcg->blkg_hint); if (blkg && blkg->q == q) return blkg; return blkg_lookup_slowpath(blkcg, q, update_hint);} /** * blkg_lookup - lookup blkg for the specified blkcg - q pair * @blkcg: blkcg of interest * @q: request_queue of interest * * Lookup blkg for the @blkcg - @q pair. This function should be called * under RCU read lock and is guaranteed to return %NULL if @q is bypassing * - see blk_queue_bypass_start() for details. */static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q){ WARN_ON_ONCE(!rcu_read_lock_held()); if (unlikely(blk_queue_bypass(q))) return NULL; return __blkg_lookup(blkcg, q, false);} /** * 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;} static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg, struct blkcg_policy *pol){ return blkcg ? blkcg->cpd[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;} static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd){ return cpd ? cpd->blkcg : 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){ return cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);} /** * 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);} /** * 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(blkcg, q); if (unlikely(!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){ if (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 int blkg_stat_init(struct blkg_stat *stat, gfp_t gfp){ int ret; ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp); if (ret) return ret;Lines 1–500 of 777. 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#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@kernel.dk> * * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it> * Paolo Valente <paolo.valente@unimore.it> * * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com> * Nauman Rafique <nauman@google.com> */ #include <linux/cgroup.h> #include <linux/percpu_counter.h> #include <linux/seq_file.h> #include <linux/radix-tree.h> #include <linux/blkdev.h> #include <linux/atomic.h> /* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */ #define BLKG_STAT_CPU_BATCH (INT_MAX / 2) /* Max limits for throttle policy */ #define THROTL_IOPS_MAX UINT_MAX #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 __rcu *blkg_hint; struct hlist_head blkg_list; struct blkcg_policy_data *cpd[BLKCG_MAX_POLS]; struct list_head all_blkcgs_node; #ifdef CONFIG_CGROUP_WRITEBACK struct list_head cgwb_list; #endif }; /* * blkg_[rw]stat->aux_cnt is excluded for local stats but included for * recursive. Used to carry stats of dead children, and, for blkg_rwstat, * to carry result values from read and sum operations. */ struct blkg_stat { struct percpu_counter cpu_cnt; atomic64_t aux_cnt; }; struct blkg_rwstat { struct percpu_counter cpu_cnt[BLKG_RWSTAT_NR]; atomic64_t aux_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 blkg:policy pair is * represented by a blkg_policy_data which is allocated and freed by each * policy's pd_alloc/free_fn() methods. A policy can allocate private data * area by allocating larger data structure which embeds blkg_policy_data * at the beginning. */ struct blkg_policy_data { /* the blkg and policy id this per-policy data belongs to */ struct blkcg_gq *blkg; int plid; }; /* * Policies that need to keep per-blkcg data which is independent from any * request_queue associated to it should implement cpd_alloc/free_fn() * methods. A policy can allocate private data area by allocating larger * data structure which embeds blkcg_policy_data at the beginning. * cpd_init() is invoked to let each policy handle per-blkcg data. */ struct blkcg_policy_data { /* the blkcg and policy id this per-policy data belongs to */ struct blkcg *blkcg; int plid; }; /* 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; /* * Each blkg gets congested separately and the congestion state is * propagated to the matching bdi_writeback_congested. */ struct bdi_writeback_congested *wb_congested; /* 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_rwstat stat_bytes; struct blkg_rwstat stat_ios; struct blkg_policy_data *pd[BLKCG_MAX_POLS]; struct rcu_head rcu_head; }; typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp); typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd); typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd); typedef void (blkcg_pol_bind_cpd_fn)(struct blkcg_policy_data *cpd); typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, int node); typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd); typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd); typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd); typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd); typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd); struct blkcg_policy { int plid; /* cgroup files for the policy */ struct cftype *dfl_cftypes; struct cftype *legacy_cftypes; /* operations */ blkcg_pol_alloc_cpd_fn *cpd_alloc_fn; blkcg_pol_init_cpd_fn *cpd_init_fn; blkcg_pol_free_cpd_fn *cpd_free_fn; blkcg_pol_bind_cpd_fn *cpd_bind_fn; blkcg_pol_alloc_pd_fn *pd_alloc_fn; 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_free_pd_fn *pd_free_fn; blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn; }; extern struct blkcg blkcg_root; extern struct cgroup_subsys_state * const blkcg_root_css; struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg, struct request_queue *q, bool update_hint); 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); const char *blkg_dev_name(struct blkcg_gq *blkg); 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); int blkg_print_stat_bytes(struct seq_file *sf, void *v); int blkg_print_stat_ios(struct seq_file *sf, void *v); int blkg_print_stat_bytes_recursive(struct seq_file *sf, void *v); int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v); u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol, int off); struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol, int off); struct blkg_conf_ctx { struct gendisk *disk; struct blkcg_gq *blkg; char *body; }; int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, 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, io_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); } static inline struct cgroup_subsys_state * task_get_blkcg_css(struct task_struct *task) { return task_get_css(task, io_cgrp_id); } /** * 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_lookup - internal version of blkg_lookup() * @blkcg: blkcg of interest * @q: request_queue of interest * @update_hint: whether to update lookup hint with the result or not * * This is internal version and shouldn't be used by policy * implementations. Looks up blkgs for the @blkcg - @q pair regardless of * @q's bypass state. If @update_hint is %true, the caller should be * holding @q->queue_lock and lookup hint is updated on success. */ static inline struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q, bool update_hint) { struct blkcg_gq *blkg; if (blkcg == &blkcg_root) return q->root_blkg; blkg = rcu_dereference(blkcg->blkg_hint); if (blkg && blkg->q == q) return blkg; return blkg_lookup_slowpath(blkcg, q, update_hint); } /** * blkg_lookup - lookup blkg for the specified blkcg - q pair * @blkcg: blkcg of interest * @q: request_queue of interest * * Lookup blkg for the @blkcg - @q pair. This function should be called * under RCU read lock and is guaranteed to return %NULL if @q is bypassing * - see blk_queue_bypass_start() for details. */ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q) { WARN_ON_ONCE(!rcu_read_lock_held()); if (unlikely(blk_queue_bypass(q))) return NULL; return __blkg_lookup(blkcg, q, false); } /** * 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; } static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg, struct blkcg_policy *pol) { return blkcg ? blkcg->cpd[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; } static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd) { return cpd ? cpd->blkcg : 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) { return cgroup_path(blkg->blkcg->css.cgroup, buf, buflen); } /** * 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); } /** * 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(blkcg, q); if (unlikely(!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) { if (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 int blkg_stat_init(struct blkg_stat *stat, gfp_t gfp) { int ret; ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp); if (ret) return ret;