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md: add new workqueue for delete rdev

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Since the purpose of call flush_workqueue in new_dev_store is to ensure
md_delayed_delete() has completed, so we should check rdev->del_work is
pending or not.

To suppress lockdep warning, we have to check mddev->del_work while
md_delayed_delete is attached to rdev->del_work, so it is not aligned
to the purpose of flush workquee. So a new workqueue is needed to avoid
the awkward situation, and introduce a new func flush_rdev_wq to flush
the new workqueue after check if there was pending work.

Also like new_dev_store, ADD_NEW_DISK ioctl has the same purpose to flush
workqueue while it holds bdev->bd_mutex, so make the same change applies
to the ioctl to avoid similar lock issue.

And md_delayed_delete actually wants to delete rdev, so rename the function
to rdev_delayed_delete.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
This commit is contained in:
Guoqing Jiang 2020-04-04 23:57:08 +02:00 committed by Song Liu
parent 21e0958ec9
commit cc1ffe61c0
1 changed files with 29 additions and 8 deletions
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37
drivers/md/md.c
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@ -89,6 +89,7 @@ static struct module *md_cluster_mod;
static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
static struct workqueue_struct *md_wq;
static struct workqueue_struct *md_misc_wq;
static struct workqueue_struct *md_rdev_misc_wq;
static int remove_and_add_spares(struct mddev *mddev,
struct md_rdev *this);
@ -2454,7 +2455,7 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
return err;
}
static void md_delayed_delete(struct work_struct *ws)
static void rdev_delayed_delete(struct work_struct *ws)
{
struct md_rdev *rdev = container_of(ws, struct md_rdev, del_work);
kobject_del(&rdev->kobj);
@ -2479,9 +2480,9 @@ static void unbind_rdev_from_array(struct md_rdev *rdev)
* to delay it due to rcu usage.
*/
synchronize_rcu();
INIT_WORK(&rdev->del_work, md_delayed_delete);
INIT_WORK(&rdev->del_work, rdev_delayed_delete);
kobject_get(&rdev->kobj);
queue_work(md_misc_wq, &rdev->del_work);
queue_work(md_rdev_misc_wq, &rdev->del_work);
}
/*
@ -4514,6 +4515,20 @@ null_show(struct mddev *mddev, char *page)
return -EINVAL;
}
/* need to ensure rdev_delayed_delete() has completed */
static void flush_rdev_wq(struct mddev *mddev)
{
struct md_rdev *rdev;
rcu_read_lock();
rdev_for_each_rcu(rdev, mddev)
if (work_pending(&rdev->del_work)) {
flush_workqueue(md_rdev_misc_wq);
break;
}
rcu_read_unlock();
}
static ssize_t
new_dev_store(struct mddev *mddev, const char *buf, size_t len)
{
@ -4541,8 +4556,7 @@ new_dev_store(struct mddev *mddev, const char *buf, size_t len)
minor != MINOR(dev))
return -EOVERFLOW;
flush_workqueue(md_misc_wq);
flush_rdev_wq(mddev);
err = mddev_lock(mddev);
if (err)
return err;
@ -4780,7 +4794,8 @@ action_store(struct mddev *mddev, const char *page, size_t len)
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
mddev_lock(mddev) == 0) {
flush_workqueue(md_misc_wq);
if (work_pending(&mddev->del_work))
flush_workqueue(md_misc_wq);
if (mddev->sync_thread) {
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
md_reap_sync_thread(mddev);
@ -7498,8 +7513,7 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
}
if (cmd == ADD_NEW_DISK)
/* need to ensure md_delayed_delete() has completed */
flush_workqueue(md_misc_wq);
flush_rdev_wq(mddev);
if (cmd == HOT_REMOVE_DISK)
/* need to ensure recovery thread has run */
@ -9471,6 +9485,10 @@ static int __init md_init(void)
if (!md_misc_wq)
goto err_misc_wq;
md_rdev_misc_wq = alloc_workqueue("md_rdev_misc", 0, 0);
if (!md_misc_wq)
goto err_rdev_misc_wq;
if ((ret = register_blkdev(MD_MAJOR, "md")) < 0)
goto err_md;
@ -9492,6 +9510,8 @@ static int __init md_init(void)
err_mdp:
unregister_blkdev(MD_MAJOR, "md");
err_md:
destroy_workqueue(md_rdev_misc_wq);
err_rdev_misc_wq:
destroy_workqueue(md_misc_wq);
err_misc_wq:
destroy_workqueue(md_wq);
@ -9778,6 +9798,7 @@ static __exit void md_exit(void)
* destroy_workqueue() below will wait for that to complete.
*/
}
destroy_workqueue(md_rdev_misc_wq);
destroy_workqueue(md_misc_wq);
destroy_workqueue(md_wq);
}