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: Roman Gushchin <guro@fb.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Dennis 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Roman Gushchin 2021-06-28 19:35:50 -07:00 committed by Linus Torvalds
parent 8826ee4fe7
commit 29264d92a0

View file

@ -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: