Commit cc1ffe61 authored by Guoqing Jiang's avatar Guoqing Jiang Committed by Song Liu
Browse files

md: add new workqueue for delete rdev 



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: default avatarGuoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
parent 21e0958e

drivers/md/md.c

+29 −8
Original line number Diff line number Diff line
@@ -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;
@@ -4780,6 +4794,7 @@ 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) {

			if (work_pending(&mddev->del_work))

				flush_workqueue(md_misc_wq);

			if (mddev->sync_thread) {

				set_bit(MD_RECOVERY_INTR, &mddev->recovery);
@@ -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);

}

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