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blk-cgroup: move struct blkcg to block/blk-cgroup.h 

There is no real need to expose the blkcg structure to the whole kernel.
Move it to the private header an expose a helper to let the writeback
code access the cgwb_list member.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2022-04-20 06:27:15 +02:00 committed by Jens Axboe
parent 397c9f46ee
commit dec223c92a
5 changed files with 45 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
block/blk-cgroup.c
View File

@ -1005,6 +1005,13 @@ static struct cftype blkcg_legacy_files[] = {
{ } /* terminate */
};
#ifdef CONFIG_CGROUP_WRITEBACK
struct list_head *blkcg_get_cgwb_list(struct cgroup_subsys_state *css)
{
return &css_to_blkcg(css)->cgwb_list;
}
#endif
/*
* blkcg destruction is a three-stage process.
*
@ -1112,7 +1119,7 @@ void blkcg_unpin_online(struct cgroup_subsys_state *blkcg_css)
static void blkcg_css_offline(struct cgroup_subsys_state *css)
{
/* this prevents anyone from attaching or migrating to this blkcg */
wb_blkcg_offline(css_to_blkcg(css));
wb_blkcg_offline(css);
/* put the base online pin allowing step 2 to be triggered */
blkcg_unpin_online(css);

28
block/blk-cgroup.h
View File

@ -17,10 +17,38 @@
#include <linux/blk-cgroup.h>
#include <linux/blk-mq.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 (INT_MAX / 2)
#ifdef CONFIG_BLK_CGROUP
struct blkcg {
struct cgroup_subsys_state css;
spinlock_t lock;
refcount_t online_pin;
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_BLK_CGROUP_FC_APPID
char fc_app_id[FC_APPID_LEN];
#endif
#ifdef CONFIG_CGROUP_WRITEBACK
struct list_head cgwb_list;
#endif
};
static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
{
return css ? container_of(css, struct blkcg, css) : NULL;
}
/*
* A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a

6
include/linux/backing-dev.h
View File

@ -17,8 +17,6 @@
#include <linux/backing-dev-defs.h>
#include <linux/slab.h>
struct blkcg;
static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi)
{
kref_get(&bdi->refcnt);
@ -154,7 +152,7 @@ struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
struct cgroup_subsys_state *memcg_css,
gfp_t gfp);
void wb_memcg_offline(struct mem_cgroup *memcg);
void wb_blkcg_offline(struct blkcg *blkcg);
void wb_blkcg_offline(struct cgroup_subsys_state *css);
/**
* inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode
@ -378,7 +376,7 @@ static inline void wb_memcg_offline(struct mem_cgroup *memcg)
{
}
static inline void wb_blkcg_offline(struct blkcg *blkcg)
static inline void wb_blkcg_offline(struct cgroup_subsys_state *css)
{
}

32
include/linux/blk-cgroup.h
View File

@ -37,29 +37,6 @@ enum blkg_iostat_type {
BLKG_IOSTAT_NR,
};
struct blkcg_gq;
struct blkg_policy_data;
struct blkcg {
struct cgroup_subsys_state css;
spinlock_t lock;
refcount_t online_pin;
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_BLK_CGROUP_FC_APPID
char fc_app_id[FC_APPID_LEN];
#endif
#ifdef CONFIG_CGROUP_WRITEBACK
struct list_head cgwb_list;
#endif
};
struct blkg_iostat {
u64 bytes[BLKG_IOSTAT_NR];
u64 ios[BLKG_IOSTAT_NR];
@ -114,11 +91,6 @@ extern struct cgroup_subsys_state * const blkcg_root_css;
void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay);
void blkcg_maybe_throttle_current(void);
static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
{
return css ? container_of(css, struct blkcg, css) : NULL;
}
/**
* bio_blkcg - grab the blkcg associated with a bio
* @bio: target bio
@ -137,12 +109,10 @@ static inline struct blkcg *bio_blkcg(struct bio *bio)
bool blk_cgroup_congested(void);
void blkcg_pin_online(struct cgroup_subsys_state *blkcg_css);
void blkcg_unpin_online(struct cgroup_subsys_state *blkcg_css);
struct list_head *blkcg_get_cgwb_list(struct cgroup_subsys_state *css);
#else /* CONFIG_BLK_CGROUP */
struct blkcg {
};
struct blkcg_gq {
};

13
mm/backing-dev.c
View File

@ -445,7 +445,6 @@ static int cgwb_create(struct backing_dev_info *bdi,
{
struct mem_cgroup *memcg;
struct cgroup_subsys_state *blkcg_css;
struct blkcg *blkcg;
struct list_head *memcg_cgwb_list, *blkcg_cgwb_list;
struct bdi_writeback *wb;
unsigned long flags;
@ -453,9 +452,8 @@ static int cgwb_create(struct backing_dev_info *bdi,
memcg = mem_cgroup_from_css(memcg_css);
blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys);
blkcg = css_to_blkcg(blkcg_css);
memcg_cgwb_list = &memcg->cgwb_list;
blkcg_cgwb_list = &blkcg->cgwb_list;
blkcg_cgwb_list = blkcg_get_cgwb_list(blkcg_css);
/* look up again under lock and discard on blkcg mismatch */
spin_lock_irqsave(&cgwb_lock, flags);
@ -723,18 +721,19 @@ void wb_memcg_offline(struct mem_cgroup *memcg)
/**
* wb_blkcg_offline - kill all wb's associated with a blkcg being offlined
* @blkcg: blkcg being offlined
* @css: blkcg being offlined
*
* Also prevents creation of any new wb's associated with @blkcg.
*/
void wb_blkcg_offline(struct blkcg *blkcg)
void wb_blkcg_offline(struct cgroup_subsys_state *css)
{
struct bdi_writeback *wb, *next;
struct list_head *list = blkcg_get_cgwb_list(css);
spin_lock_irq(&cgwb_lock);
list_for_each_entry_safe(wb, next, &blkcg->cgwb_list, blkcg_node)
list_for_each_entry_safe(wb, next, list, blkcg_node)
cgwb_kill(wb);
blkcg->cgwb_list.next = NULL; /* prevent new wb's */
list->next = NULL; /* prevent new wb's */
spin_unlock_irq(&cgwb_lock);
}