375 lines
10 KiB
C
375 lines
10 KiB
C
#ifndef _BLK_CGROUP_H
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#define _BLK_CGROUP_H
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/*
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* Common Block IO controller cgroup interface
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*
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* Based on ideas and code from CFQ, CFS and BFQ:
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* Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
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*
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* Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
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* Paolo Valente <paolo.valente@unimore.it>
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*
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* Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
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* Nauman Rafique <nauman@google.com>
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*/
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#include <linux/cgroup.h>
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#include <linux/u64_stats_sync.h>
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#include <linux/seq_file.h>
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/* Max limits for throttle policy */
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#define THROTL_IOPS_MAX UINT_MAX
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/* CFQ specific, out here for blkcg->cfq_weight */
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#define CFQ_WEIGHT_MIN 10
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#define CFQ_WEIGHT_MAX 1000
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#define CFQ_WEIGHT_DEFAULT 500
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#ifdef CONFIG_BLK_CGROUP
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enum blkg_rwstat_type {
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BLKG_RWSTAT_READ,
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BLKG_RWSTAT_WRITE,
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BLKG_RWSTAT_SYNC,
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BLKG_RWSTAT_ASYNC,
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BLKG_RWSTAT_NR,
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BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
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};
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struct blkio_cgroup {
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struct cgroup_subsys_state css;
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spinlock_t lock;
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struct hlist_head blkg_list;
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/* for policies to test whether associated blkcg has changed */
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uint64_t id;
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/* TODO: per-policy storage in blkio_cgroup */
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unsigned int cfq_weight; /* belongs to cfq */
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};
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struct blkg_stat {
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struct u64_stats_sync syncp;
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uint64_t cnt;
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};
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struct blkg_rwstat {
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struct u64_stats_sync syncp;
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uint64_t cnt[BLKG_RWSTAT_NR];
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};
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/* per-blkg per-policy data */
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struct blkg_policy_data {
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/* the blkg this per-policy data belongs to */
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struct blkio_group *blkg;
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/* used during policy activation */
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struct list_head alloc_node;
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/* pol->pdata_size bytes of private data used by policy impl */
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char pdata[] __aligned(__alignof__(unsigned long long));
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};
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struct blkio_group {
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/* Pointer to the associated request_queue */
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struct request_queue *q;
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struct list_head q_node;
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struct hlist_node blkcg_node;
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struct blkio_cgroup *blkcg;
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/* reference count */
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int refcnt;
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struct blkg_policy_data *pd[BLKCG_MAX_POLS];
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struct rcu_head rcu_head;
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};
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typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
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typedef void (blkio_exit_group_fn)(struct blkio_group *blkg);
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typedef void (blkio_reset_group_stats_fn)(struct blkio_group *blkg);
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struct blkio_policy_ops {
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blkio_init_group_fn *blkio_init_group_fn;
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blkio_exit_group_fn *blkio_exit_group_fn;
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blkio_reset_group_stats_fn *blkio_reset_group_stats_fn;
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};
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struct blkio_policy_type {
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struct blkio_policy_ops ops;
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int plid;
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/* policy specific private data size */
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size_t pdata_size;
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/* cgroup files for the policy */
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struct cftype *cftypes;
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};
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extern struct blkio_cgroup blkio_root_cgroup;
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struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
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struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
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struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
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struct request_queue *q);
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struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
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struct request_queue *q);
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int blkcg_init_queue(struct request_queue *q);
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void blkcg_drain_queue(struct request_queue *q);
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void blkcg_exit_queue(struct request_queue *q);
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/* Blkio controller policy registration */
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int blkio_policy_register(struct blkio_policy_type *);
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void blkio_policy_unregister(struct blkio_policy_type *);
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int blkcg_activate_policy(struct request_queue *q,
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const struct blkio_policy_type *pol);
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void blkcg_deactivate_policy(struct request_queue *q,
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const struct blkio_policy_type *pol);
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void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg,
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u64 (*prfill)(struct seq_file *, void *, int),
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const struct blkio_policy_type *pol, int data,
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bool show_total);
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u64 __blkg_prfill_u64(struct seq_file *sf, void *pdata, u64 v);
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u64 __blkg_prfill_rwstat(struct seq_file *sf, void *pdata,
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const struct blkg_rwstat *rwstat);
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u64 blkg_prfill_stat(struct seq_file *sf, void *pdata, int off);
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u64 blkg_prfill_rwstat(struct seq_file *sf, void *pdata, int off);
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struct blkg_conf_ctx {
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struct gendisk *disk;
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struct blkio_group *blkg;
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u64 v;
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};
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int blkg_conf_prep(struct blkio_cgroup *blkcg,
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const struct blkio_policy_type *pol, const char *input,
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struct blkg_conf_ctx *ctx);
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void blkg_conf_finish(struct blkg_conf_ctx *ctx);
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/**
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* blkg_to_pdata - get policy private data
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* @blkg: blkg of interest
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* @pol: policy of interest
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*
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* Return pointer to private data associated with the @blkg-@pol pair.
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*/
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static inline void *blkg_to_pdata(struct blkio_group *blkg,
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struct blkio_policy_type *pol)
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{
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return blkg ? blkg->pd[pol->plid]->pdata : NULL;
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}
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/**
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* pdata_to_blkg - get blkg associated with policy private data
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* @pdata: policy private data of interest
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*
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* @pdata is policy private data. Determine the blkg it's associated with.
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*/
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static inline struct blkio_group *pdata_to_blkg(void *pdata)
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{
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if (pdata) {
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struct blkg_policy_data *pd =
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container_of(pdata, struct blkg_policy_data, pdata);
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return pd->blkg;
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}
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return NULL;
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}
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/**
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* blkg_path - format cgroup path of blkg
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* @blkg: blkg of interest
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* @buf: target buffer
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* @buflen: target buffer length
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*
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* Format the path of the cgroup of @blkg into @buf.
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*/
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static inline int blkg_path(struct blkio_group *blkg, char *buf, int buflen)
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{
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int ret;
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rcu_read_lock();
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ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
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rcu_read_unlock();
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if (ret)
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strncpy(buf, "<unavailable>", buflen);
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return ret;
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}
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/**
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* blkg_get - get a blkg reference
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* @blkg: blkg to get
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*
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* The caller should be holding queue_lock and an existing reference.
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*/
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static inline void blkg_get(struct blkio_group *blkg)
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{
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lockdep_assert_held(blkg->q->queue_lock);
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WARN_ON_ONCE(!blkg->refcnt);
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blkg->refcnt++;
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}
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void __blkg_release(struct blkio_group *blkg);
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/**
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* blkg_put - put a blkg reference
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* @blkg: blkg to put
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*
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* The caller should be holding queue_lock.
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*/
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static inline void blkg_put(struct blkio_group *blkg)
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{
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lockdep_assert_held(blkg->q->queue_lock);
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WARN_ON_ONCE(blkg->refcnt <= 0);
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if (!--blkg->refcnt)
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__blkg_release(blkg);
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}
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/**
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* blkg_stat_add - add a value to a blkg_stat
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* @stat: target blkg_stat
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* @val: value to add
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*
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* Add @val to @stat. The caller is responsible for synchronizing calls to
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* this function.
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*/
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static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
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{
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u64_stats_update_begin(&stat->syncp);
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stat->cnt += val;
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u64_stats_update_end(&stat->syncp);
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}
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/**
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* blkg_stat_read - read the current value of a blkg_stat
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* @stat: blkg_stat to read
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*
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* Read the current value of @stat. This function can be called without
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* synchroniztion and takes care of u64 atomicity.
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*/
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static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
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{
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unsigned int start;
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uint64_t v;
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do {
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start = u64_stats_fetch_begin(&stat->syncp);
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v = stat->cnt;
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} while (u64_stats_fetch_retry(&stat->syncp, start));
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return v;
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}
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/**
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* blkg_stat_reset - reset a blkg_stat
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* @stat: blkg_stat to reset
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*/
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static inline void blkg_stat_reset(struct blkg_stat *stat)
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{
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stat->cnt = 0;
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}
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/**
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* blkg_rwstat_add - add a value to a blkg_rwstat
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* @rwstat: target blkg_rwstat
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* @rw: mask of REQ_{WRITE|SYNC}
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* @val: value to add
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*
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* Add @val to @rwstat. The counters are chosen according to @rw. The
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* caller is responsible for synchronizing calls to this function.
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*/
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static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
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int rw, uint64_t val)
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{
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u64_stats_update_begin(&rwstat->syncp);
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if (rw & REQ_WRITE)
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rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
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else
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rwstat->cnt[BLKG_RWSTAT_READ] += val;
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if (rw & REQ_SYNC)
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rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
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else
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rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
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u64_stats_update_end(&rwstat->syncp);
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}
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/**
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* blkg_rwstat_read - read the current values of a blkg_rwstat
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* @rwstat: blkg_rwstat to read
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*
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* Read the current snapshot of @rwstat and return it as the return value.
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* This function can be called without synchronization and takes care of
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* u64 atomicity.
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*/
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static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
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{
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unsigned int start;
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struct blkg_rwstat tmp;
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do {
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start = u64_stats_fetch_begin(&rwstat->syncp);
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tmp = *rwstat;
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} while (u64_stats_fetch_retry(&rwstat->syncp, start));
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return tmp;
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}
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/**
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* blkg_rwstat_sum - read the total count of a blkg_rwstat
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* @rwstat: blkg_rwstat to read
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*
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* Return the total count of @rwstat regardless of the IO direction. This
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* function can be called without synchronization and takes care of u64
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* atomicity.
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*/
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static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat)
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{
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struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
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return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
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}
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/**
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* blkg_rwstat_reset - reset a blkg_rwstat
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* @rwstat: blkg_rwstat to reset
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*/
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static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
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{
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memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
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}
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#else /* CONFIG_BLK_CGROUP */
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struct cgroup;
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struct blkio_group {
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};
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struct blkio_policy_type {
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};
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static inline struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
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static inline struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio) { return NULL; }
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static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg, void *key) { return NULL; }
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static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
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static inline void blkcg_drain_queue(struct request_queue *q) { }
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static inline void blkcg_exit_queue(struct request_queue *q) { }
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static inline int blkio_policy_register(struct blkio_policy_type *blkiop) { return 0; }
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static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
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static inline int blkcg_activate_policy(struct request_queue *q,
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const struct blkio_policy_type *pol) { return 0; }
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static inline void blkcg_deactivate_policy(struct request_queue *q,
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const struct blkio_policy_type *pol) { }
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static inline void *blkg_to_pdata(struct blkio_group *blkg,
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struct blkio_policy_type *pol) { return NULL; }
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static inline struct blkio_group *pdata_to_blkg(void *pdata,
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struct blkio_policy_type *pol) { return NULL; }
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static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
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static inline void blkg_get(struct blkio_group *blkg) { }
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static inline void blkg_put(struct blkio_group *blkg) { }
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#endif /* CONFIG_BLK_CGROUP */
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#endif /* _BLK_CGROUP_H */
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