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Commit 902ec5b6 authored by Shaohua Li's avatar Shaohua Li Committed by Jens Axboe
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block: make blkcg aware of kthread stored original cgroup info 



bio_blkcg is the only API to get cgroup info for a bio right now. If
bio_blkcg finds current task is a kthread and has original blkcg
associated, it will use the css instead of associating the bio to
current task. This makes it possible that kthread dispatches bios on
behalf of other threads.

Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent af551fb3

include/linux/blk-cgroup.h

+7 −6
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/radix-tree.h>

#include <linux/blkdev.h>

#include <linux/atomic.h>

#include <linux/kthread.h>



/* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */

#define BLKG_STAT_CPU_BATCH	(INT_MAX / 2)
@@ -223,16 +224,16 @@ static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css) 
	return css ? container_of(css, struct blkcg, css) : NULL;

}



static inline struct blkcg *task_blkcg(struct task_struct *tsk)

{

	return css_to_blkcg(task_css(tsk, io_cgrp_id));

}



static inline struct blkcg *bio_blkcg(struct bio *bio)

{

	struct cgroup_subsys_state *css;



	if (bio && bio->bi_css)

		return css_to_blkcg(bio->bi_css);

	return task_blkcg(current);

	css = kthread_blkcg();

	if (css)

		return css_to_blkcg(css);

	return css_to_blkcg(task_css(current, io_cgrp_id));

}



/**