md: remove special meaning of ->quiesce(.., 2)

The '2' argument means "wake up anything that is waiting".
This is an inelegant part of the design and was added
to help support management of suspend_lo/suspend_hi setting.
Now that suspend_lo/hi is managed in mddev_suspend/resume,
that need is gone.
These is still a couple of places where we call 'quiesce'
with an argument of '2', but they can safely be changed to
call ->quiesce(.., 1); ->quiesce(.., 0) which
achieve the same result at the small cost of pausing IO
briefly.

This removes a small "optimization" from suspend_{hi,lo}_store,
but it isn't clear that optimization served a useful purpose.
The code now is a lot clearer.

Suggested-by: Shaohua Li <shli@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

1 files changed, 10 insertions, 24 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9155f00dca20..d441b1d9846c 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4846,7 +4846,7 @@ suspend_lo_show(struct mddev *mddev, char *page)
 static ssize_t
 suspend_lo_store(struct mddev *mddev, const char *buf, size_t len)
 {
-	unsigned long long old, new;
+	unsigned long long new;
 	int err;
 
 	err = kstrtoull(buf, 10, &new);
@@ -4862,17 +4862,10 @@ suspend_lo_store(struct mddev *mddev, const char *buf, size_t len)
 	if (mddev->pers == NULL ||
 	    mddev->pers->quiesce == NULL)
 		goto unlock;
-	old = mddev->suspend_lo;
+	mddev_suspend(mddev);
 	mddev->suspend_lo = new;
-	if (new >= old) {
-		/* Shrinking suspended region */
-		wake_up(&mddev->sb_wait);
-		mddev->pers->quiesce(mddev, 2);
-	} else {
-		/* Expanding suspended region - need to wait */
-		mddev_suspend(mddev);
-		mddev_resume(mddev);
-	}
+	mddev_resume(mddev);
+
 	err = 0;
 unlock:
 	mddev_unlock(mddev);
@@ -4890,7 +4883,7 @@ suspend_hi_show(struct mddev *mddev, char *page)
 static ssize_t
 suspend_hi_store(struct mddev *mddev, const char *buf, size_t len)
 {
-	unsigned long long old, new;
+	unsigned long long new;
 	int err;
 
 	err = kstrtoull(buf, 10, &new);
@@ -4903,20 +4896,13 @@ suspend_hi_store(struct mddev *mddev, const char *buf, size_t len)
 	if (err)
 		return err;
 	err = -EINVAL;
-	if (mddev->pers == NULL ||
-	    mddev->pers->quiesce == NULL)
+	if (mddev->pers == NULL)
 		goto unlock;
-	old = mddev->suspend_hi;
+
+	mddev_suspend(mddev);
 	mddev->suspend_hi = new;
-	if (new <= old) {
-		/* Shrinking suspended region */
-		wake_up(&mddev->sb_wait);
-		mddev->pers->quiesce(mddev, 2);
-	} else {
-		/* Expanding suspended region - need to wait */
-		mddev_suspend(mddev);
-		mddev_resume(mddev);
-	}
+	mddev_resume(mddev);
+
 	err = 0;
 unlock:
 	mddev_unlock(mddev);