[PATCH -next v4 17/19] md: suspend array in md_start_sync() if array need reconfiguration

[Yu Kuai]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

So that io won't concurrent with array reconfiguration, and it's safe to
suspend the array directly because normal io won't rely on
md_start_sync().

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
 drivers/md/md.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 77ba8b265e16..42f5fbde4e89 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9417,8 +9417,13 @@ static void md_start_sync(struct work_struct *ws)
 {
 	struct mddev *mddev = container_of(ws, struct mddev, sync_work);
 	int spares = 0;
+	bool suspend = false;
 
-	mddev_lock_nointr(mddev);
+	if (md_spares_need_change(mddev))
+		suspend = true;
+
+	suspend ? mddev_suspend_and_lock_nointr(mddev) :
+		  mddev_lock_nointr(mddev);
 
 	if (!md_is_rdwr(mddev)) {
 		/*
@@ -9454,7 +9459,7 @@ static void md_start_sync(struct work_struct *ws)
 		goto not_running;
 	}
 
-	mddev_unlock(mddev);
+	suspend ? mddev_unlock_and_resume(mddev) : mddev_unlock(mddev);
 	md_wakeup_thread(mddev->sync_thread);
 	sysfs_notify_dirent_safe(mddev->sysfs_action);
 	md_new_event();
@@ -9466,7 +9471,7 @@ static void md_start_sync(struct work_struct *ws)
 	clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
 	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
 	clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
-	mddev_unlock(mddev);
+	suspend ? mddev_unlock_and_resume(mddev) : mddev_unlock(mddev);
 
 	wake_up(&resync_wait);
 	if (test_and_clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery) &&
-- 
2.39.2