/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _BLK_CGROUP_PRIVATE_H #define _BLK_CGROUP_PRIVATE_H /* * block cgroup private header * * Based on ideas and code from CFQ, CFS and BFQ: * Copyright (C) 2003 Jens Axboe <[email protected]> * * Copyright (C) 2008 Fabio Checconi <[email protected]> * Paolo Valente <[email protected]> * * Copyright (C) 2009 Vivek Goyal <[email protected]> * Nauman Rafique <[email protected]> */ #include <linux/blk-cgroup.h> #include <linux/cgroup.h> #include <linux/kthread.h> #include <linux/blk-mq.h> #include <linux/llist.h> #include "blk.h" struct blkcg_gq; struct blkg_policy_data; /* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */ #define BLKG_STAT_CPU_BATCH … #ifdef CONFIG_BLK_CGROUP enum blkg_iostat_type { … }; struct blkg_iostat { … }; struct blkg_iostat_set { … }; /* association between a blk cgroup and a request queue */ struct blkcg_gq { … }; struct blkcg { … }; static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css) { … } /* * 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 { … }; /* * 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 { … }; blkcg_pol_alloc_cpd_fn; blkcg_pol_init_cpd_fn; blkcg_pol_free_cpd_fn; blkcg_pol_bind_cpd_fn; blkcg_pol_alloc_pd_fn; blkcg_pol_init_pd_fn; blkcg_pol_online_pd_fn; blkcg_pol_offline_pd_fn; blkcg_pol_free_pd_fn; blkcg_pol_reset_pd_stats_fn; blkcg_pol_stat_pd_fn; struct blkcg_policy { … }; extern struct blkcg blkcg_root; extern bool blkcg_debug_stats; void blkg_init_queue(struct request_queue *q); int blkcg_init_disk(struct gendisk *disk); void blkcg_exit_disk(struct gendisk *disk); /* 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 gendisk *disk, const struct blkcg_policy *pol); void blkcg_deactivate_policy(struct gendisk *disk, 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); struct blkg_conf_ctx { … }; void blkg_conf_init(struct blkg_conf_ctx *ctx, char *input); int blkg_conf_open_bdev(struct blkg_conf_ctx *ctx); int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, struct blkg_conf_ctx *ctx); void blkg_conf_exit(struct blkg_conf_ctx *ctx); /** * bio_issue_as_root_blkg - see if this bio needs to be issued as root blkg * @return: true if this bio needs to be submitted with the root blkg context. * * In order to avoid priority inversions we sometimes need to issue a bio as if * it were attached to the root blkg, and then backcharge to the actual owning * blkg. The idea is we do bio_blkcg_css() to look up the actual context for * the bio and attach the appropriate blkg to the bio. Then we call this helper * and if it is true run with the root blkg for that queue and then do any * backcharging to the originating cgroup once the io is complete. */ static inline bool bio_issue_as_root_blkg(struct bio *bio) { … } /** * 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. * Must be called in a RCU critical section. */ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q) { … } /** * 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) { … } static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg, struct blkcg_policy *pol) { … } /** * 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) { … } static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd) { … } /** * 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) { … } /** * blkg_tryget - try and get a blkg reference * @blkg: blkg to get * * This is for use when doing an RCU lookup of the blkg. We may be in the midst * of freeing this blkg, so we can only use it if the refcnt is not zero. */ static inline bool blkg_tryget(struct blkcg_gq *blkg) { … } /** * blkg_put - put a blkg reference * @blkg: blkg to put */ static inline void blkg_put(struct blkcg_gq *blkg) { … } /** * 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) … /** * 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) … static inline void blkcg_bio_issue_init(struct bio *bio) { … } static inline void blkcg_use_delay(struct blkcg_gq *blkg) { … } static inline int blkcg_unuse_delay(struct blkcg_gq *blkg) { … } /** * blkcg_set_delay - Enable allocator delay mechanism with the specified delay amount * @blkg: target blkg * @delay: delay duration in nsecs * * When enabled with this function, the delay is not decayed and must be * explicitly cleared with blkcg_clear_delay(). Must not be mixed with * blkcg_[un]use_delay() and blkcg_add_delay() usages. */ static inline void blkcg_set_delay(struct blkcg_gq *blkg, u64 delay) { … } /** * blkcg_clear_delay - Disable allocator delay mechanism * @blkg: target blkg * * Disable use_delay mechanism. See blkcg_set_delay(). */ static inline void blkcg_clear_delay(struct blkcg_gq *blkg) { … } /** * blk_cgroup_mergeable - Determine whether to allow or disallow merges * @rq: request to merge into * @bio: bio to merge * * @bio and @rq should belong to the same cgroup and their issue_as_root should * match. The latter is necessary as we don't want to throttle e.g. a metadata * update because it happens to be next to a regular IO. */ static inline bool blk_cgroup_mergeable(struct request *rq, struct bio *bio) { … } void blk_cgroup_bio_start(struct bio *bio); void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta); #else /* CONFIG_BLK_CGROUP */ struct blkg_policy_data { }; struct blkcg_policy_data { }; struct blkcg_policy { }; struct blkcg { }; static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; } static inline void blkg_init_queue(struct request_queue *q) { } static inline int blkcg_init_disk(struct gendisk *disk) { return 0; } static inline void blkcg_exit_disk(struct gendisk *disk) { } 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 gendisk *disk, const struct blkcg_policy *pol) { return 0; } static inline void blkcg_deactivate_policy(struct gendisk *disk, const struct blkcg_policy *pol) { } 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 void blkcg_bio_issue_init(struct bio *bio) { } static inline void blk_cgroup_bio_start(struct bio *bio) { } static inline bool blk_cgroup_mergeable(struct request *rq, struct bio *bio) { return true; } #define blk_queue_for_each_rl … #endif /* CONFIG_BLK_CGROUP */ #endif /* _BLK_CGROUP_PRIVATE_H */
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