Commit dec223c9 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-8-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 397c9f46

block/blk-cgroup.c

+8 −1
Original line number Diff line number Diff line
@@ -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);

block/blk-cgroup.h

+28 −0
Original line number Diff line number Diff line
@@ -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

include/linux/backing-dev.h

+2 −4
Original line number Diff line number Diff line
@@ -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)

{

}

include/linux/blk-cgroup.h

+1 −31
Original line number Diff line number Diff line
@@ -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 {

};

mm/backing-dev.c

+6 −7
Original line number Diff line number Diff line
@@ -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);

}