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Commit c839e7a0 authored by Dennis Zhou (Facebook)'s avatar Dennis Zhou (Facebook) Committed by Jens Axboe
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blkcg: remove bio->bi_css and instead use bio->bi_blkg 



Prior patches ensured that all bios are now associated with some blkg.
This now makes bio->bi_css unnecessary as blkg maintains a reference to
the blkcg already.

This patch removes the field bi_css and transfers corresponding uses to
access via bi_blkg.

Signed-off-by: default avatarDennis Zhou <dennisszhou@gmail.com>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent bdc24917

block/bio.c

+11 −45
Original line number Diff line number Diff line
@@ -609,7 +609,7 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src) 
	bio->bi_iter = bio_src->bi_iter;

	bio->bi_io_vec = bio_src->bi_io_vec;



	bio_clone_blkcg_association(bio, bio_src);

	bio_clone_blkg_association(bio, bio_src);



	blkcg_bio_issue_init(bio);

}
@@ -1956,34 +1956,6 @@ EXPORT_SYMBOL(bioset_init_from_src); 


#ifdef CONFIG_BLK_CGROUP



/**

 * bio_associate_blkcg - associate a bio with the specified blkcg

 * @bio: target bio

 * @blkcg_css: css of the blkcg to associate

 *

 * Associate @bio with the blkcg specified by @blkcg_css.  Block layer will

 * treat @bio as if it were issued by a task which belongs to the blkcg.

 *

 * This function takes an extra reference of @blkcg_css which will be put

 * when @bio is released.  The caller must own @bio and is responsible for

 * synchronizing calls to this function.  If @blkcg_css is NULL, a call to

 * blkcg_get_css finds the current css from the kthread or task.

 */

int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css)

{

	if (unlikely(bio->bi_css))

		return -EBUSY;



	if (blkcg_css)

		css_get(blkcg_css);

	else

		blkcg_css = blkcg_get_css();



	bio->bi_css = blkcg_css;

	return 0;

}

EXPORT_SYMBOL_GPL(bio_associate_blkcg);



/**

 * bio_associate_blkg - associate a bio with the a blkg

 * @bio: target bio
@@ -2033,7 +2005,6 @@ int bio_associate_blkg_from_css(struct bio *bio, 
				struct cgroup_subsys_state *css)

{

	css_get(css);

	bio->bi_css = css;

	return __bio_associate_blkg_from_css(bio, css);

}

EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css);
@@ -2054,12 +2025,11 @@ int bio_associate_blkg_from_page(struct bio *bio, struct page *page) 
{

	struct cgroup_subsys_state *css;



	if (unlikely(bio->bi_css))

	if (unlikely(bio->bi_blkg))

		return -EBUSY;

	if (!page->mem_cgroup)

		return 0;

	css = cgroup_get_e_css(page->mem_cgroup->css.cgroup, &io_cgrp_subsys);

	bio->bi_css = css;



	return __bio_associate_blkg_from_css(bio, css);

}
@@ -2085,8 +2055,7 @@ int bio_associate_create_blkg(struct request_queue *q, struct bio *bio) 


	rcu_read_lock();



	bio_associate_blkcg(bio, NULL);

	blkcg = bio_blkcg(bio);

	blkcg = css_to_blkcg(blkcg_get_css());



	if (!blkcg->css.parent) {

		ret = bio_associate_blkg(bio, q->root_blkg);
@@ -2110,30 +2079,27 @@ void bio_disassociate_task(struct bio *bio) 
		put_io_context(bio->bi_ioc);

		bio->bi_ioc = NULL;

	}

	if (bio->bi_css) {

		css_put(bio->bi_css);

		bio->bi_css = NULL;

	}

	if (bio->bi_blkg) {

		/* a ref is always taken on css */

		css_put(&bio_blkcg(bio)->css);

		blkg_put(bio->bi_blkg);

		bio->bi_blkg = NULL;

	}

}



/**

 * bio_clone_blkcg_association - clone blkcg association from src to dst bio

 * bio_clone_blkg_association - clone blkg association from src to dst bio

 * @dst: destination bio

 * @src: source bio

 */

void bio_clone_blkcg_association(struct bio *dst, struct bio *src)

void bio_clone_blkg_association(struct bio *dst, struct bio *src)

{

	if (src->bi_css)

		WARN_ON(bio_associate_blkcg(dst, src->bi_css));



	if (src->bi_blkg)

	if (src->bi_blkg) {

		css_get(&bio_blkcg(src)->css);

		bio_associate_blkg(dst, src->bi_blkg);

	}

EXPORT_SYMBOL_GPL(bio_clone_blkcg_association);

}

EXPORT_SYMBOL_GPL(bio_clone_blkg_association);

#endif /* CONFIG_BLK_CGROUP */



static void __init biovec_init_slabs(void)

block/bounce.c

+1 −1
Original line number Diff line number Diff line
@@ -257,7 +257,7 @@ static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask, 
		}

	}



	bio_clone_blkcg_association(bio, bio_src);

	bio_clone_blkg_association(bio, bio_src);



	blkcg_bio_issue_init(bio);

drivers/block/loop.c

+3 −2
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ 
#include <linux/falloc.h>

#include <linux/uio.h>

#include <linux/ioprio.h>

#include <linux/blk-cgroup.h>



#include "loop.h"
@@ -1760,8 +1761,8 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, 


	/* always use the first bio's css */

#ifdef CONFIG_BLK_CGROUP

	if (cmd->use_aio && rq->bio && rq->bio->bi_css) {

		cmd->css = rq->bio->bi_css;

	if (cmd->use_aio && rq->bio && rq->bio->bi_blkg) {

		cmd->css = &bio_blkcg(rq->bio)->css;

		css_get(cmd->css);

	} else

#endif

drivers/md/raid0.c

+1 −1
Original line number Diff line number Diff line
@@ -542,7 +542,7 @@ static void raid0_handle_discard(struct mddev *mddev, struct bio *bio) 
		    !discard_bio)

			continue;

		bio_chain(discard_bio, bio);

		bio_clone_blkcg_association(discard_bio, bio);

		bio_clone_blkg_association(discard_bio, bio);

		if (mddev->gendisk)

			trace_block_bio_remap(bdev_get_queue(rdev->bdev),

				discard_bio, disk_devt(mddev->gendisk),

include/linux/bio.h

+3 −6
Original line number Diff line number Diff line
@@ -540,23 +540,20 @@ static inline int bio_associate_blkg_from_page(struct bio *bio, 
#endif



#ifdef CONFIG_BLK_CGROUP

int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);

int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg);

int bio_associate_blkg_from_css(struct bio *bio,

				struct cgroup_subsys_state *css);

int bio_associate_create_blkg(struct request_queue *q, struct bio *bio);

void bio_disassociate_task(struct bio *bio);

void bio_clone_blkcg_association(struct bio *dst, struct bio *src);

void bio_clone_blkg_association(struct bio *dst, struct bio *src);

#else	/* CONFIG_BLK_CGROUP */

static inline int bio_associate_blkcg(struct bio *bio,

			struct cgroup_subsys_state *blkcg_css) { return 0; }

static inline int bio_associate_blkg_from_css(struct bio *bio,

					      struct cgroup_subsys_state *css)

{ return 0; }

static inline int bio_associate_create_blkg(struct request_queue *q,

					    struct bio *bio) { return 0; }

static inline void bio_disassociate_task(struct bio *bio) { }

static inline void bio_clone_blkcg_association(struct bio *dst,

static inline void bio_clone_blkg_association(struct bio *dst,

					      struct bio *src) { }

#endif	/* CONFIG_BLK_CGROUP */