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@xxxxxxxxxxxxxxx>
---
drivers/md/md.c | 37 +++++++++++++++++++++++++++++--------
1 file changed, 29 insertions(+), 8 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2c23046fca57..2202074ea98f 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -87,6 +87,7 @@ 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);
@@ -2452,7 +2453,7 @@ 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);
@@ -2477,9 +2478,9 @@ 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);
}
/*
@@ -4512,6 +4513,20 @@ 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)
{
@@ -4539,8 +4554,7 @@ 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;
@@ -4778,7 +4792,8 @@ 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);
@@ -7497,8 +7512,7 @@ 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 */
@@ -9470,6 +9484,10 @@ 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;
@@ -9491,6 +9509,8 @@ 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);
@@ -9777,6 +9797,7 @@ 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);
}
--
2.17.1
