The patch titled
Subject: writeback, cgroup: switch to rcu_work API in inode_switch_wbs()
has been added to the -mm tree. Its filename is
writeback-cgroup-switch-to-rcu_work-api-in-inode_switch_wbs.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/writeback-cgroup-switch-to-rcu_work-api-in-inode_switch_wbs.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/writeback-cgroup-switch-to-rcu_work-api-in-inode_switch_wbs.patch
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------------------------------------------------------
From: Roman Gushchin <guro@xxxxxx>
Subject: 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@xxxxxx
Signed-off-by: Roman Gushchin <guro@xxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Acked-by: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Dave Chinner <dchinner@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/fs-writeback.c | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)
--- a/fs/fs-writeback.c~writeback-cgroup-switch-to-rcu_work-api-in-inode_switch_wbs
+++ a/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
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 @@ skip_switch:
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 inod
* 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:
_
Patches currently in -mm which might be from guro@xxxxxx are
writeback-cgroup-do-not-switch-inodes-with-i_will_free-flag.patch
writeback-cgroup-add-smp_mb-to-cgroup_writeback_umount.patch
writeback-cgroup-increment-isw_nr_in_flight-before-grabbing-an-inode.patch
writeback-cgroup-switch-to-rcu_work-api-in-inode_switch_wbs.patch
writeback-cgroup-keep-list-of-inodes-attached-to-bdi_writeback.patch
writeback-cgroup-split-out-the-functional-part-of-inode_switch_wbs_work_fn.patch
writeback-cgroup-support-switching-multiple-inodes-at-once.patch
writeback-cgroup-release-dying-cgwbs-by-switching-attached-inodes.patch
