On Wed 02-06-21 17:55:13, Roman Gushchin wrote:
> 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.
>
> Signed-off-by: Roman Gushchin <guro@xxxxxx>
Looks good to me. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/fs-writeback.c | 18 ++++--------------
> 1 file changed, 4 insertions(+), 14 deletions(-)
>
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index e91980f49388..1f51857e41d1 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -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
> @@ -534,7 +523,8 @@ 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);
>
> atomic_inc(&isw_nr_in_flight);
> return;
> --
> 2.31.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
