Commit 29264d92 authored by Roman Gushchin's avatar Roman Gushchin Committed by Linus Torvalds
Browse files

writeback, cgroup: switch to rcu_work API in inode_switch_wbs() 

Inode's wb switching requires two steps divided by an RCU grace period.
It's currently implemented as an RCU callback inode_switch_wbs_rcu_fn(),
which schedules inode_switch_wbs_work_fn() as a work.

Switching to the rcu_work API allows to do the same in a cleaner and
slightly shorter form.

Link: https://lkml.kernel.org/r/20210608230225.2078447-5-guro@fb.com


Signed-off-by: default avatarRoman Gushchin <guro@fb.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarDennis Zhou <dennis@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Jan Kara <jack@suse.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8826ee4f

fs/fs-writeback.c

+4 −14
Original line number Diff line number Diff line
@@ -335,8 +335,7 @@ struct inode_switch_wbs_context { 
	struct inode		*inode;

	struct bdi_writeback	*new_wb;



	struct rcu_head		rcu_head;

	struct work_struct	work;

	struct rcu_work		work;

};



static void bdi_down_write_wb_switch_rwsem(struct backing_dev_info *bdi)
@@ -352,7 +351,7 @@ static void bdi_up_write_wb_switch_rwsem(struct backing_dev_info *bdi) 
static void inode_switch_wbs_work_fn(struct work_struct *work)

{

	struct inode_switch_wbs_context *isw =

		container_of(work, struct inode_switch_wbs_context, work);

		container_of(to_rcu_work(work), struct inode_switch_wbs_context, work);

	struct inode *inode = isw->inode;

	struct backing_dev_info *bdi = inode_to_bdi(inode);

	struct address_space *mapping = inode->i_mapping;
@@ -469,16 +468,6 @@ static void inode_switch_wbs_work_fn(struct work_struct *work) 
	atomic_dec(&isw_nr_in_flight);

}



static void inode_switch_wbs_rcu_fn(struct rcu_head *rcu_head)

{

	struct inode_switch_wbs_context *isw = container_of(rcu_head,

				struct inode_switch_wbs_context, rcu_head);



	/* needs to grab bh-unsafe locks, bounce to work item */

	INIT_WORK(&isw->work, inode_switch_wbs_work_fn);

	queue_work(isw_wq, &isw->work);

}



/**

 * inode_switch_wbs - change the wb association of an inode

 * @inode: target inode
@@ -536,7 +525,8 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id) 
	 * lock so that stat transfer can synchronize against them.

	 * Let's continue after I_WB_SWITCH is guaranteed to be visible.

	 */

	call_rcu(&isw->rcu_head, inode_switch_wbs_rcu_fn);

	INIT_RCU_WORK(&isw->work, inode_switch_wbs_work_fn);

	queue_rcu_work(isw_wq, &isw->work);

	return;



out_free: