[PATCH] 9p/xen: fix init sequence

[Alexander Merritt <alexander@edera.dev>]

From: Alex Zenla <alex@edera.dev>

Large amount of mount hangs observed during hotplugging of 9pfs devices. The
9pfs Xen driver attempts to initialize itself more than once, causing the
frontend and backend to disagree: the backend listens on a channel that the
frontend does not send on, resulting in stalled processing.

Only allow initialization of 9p frontend once.

Fixes: c15fe55d14b3b ("9p/xen: fix connection sequence")
Signed-off-by: Alex Zenla <alex@edera.dev>
Signed-off-by: Alexander Merritt <alexander@edera.dev>
Signed-off-by: Ariadne Conill <ariadne@ariadne.space>
---
 net/9p/trans_xen.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index dfdbe1ca5338..0304e8a1616d 100644
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -465,6 +465,7 @@ static int xen_9pfs_front_init(struct xenbus_device *dev)
 		goto error;
 	}
 
+	xenbus_switch_state(dev, XenbusStateInitialised);
 	return 0;
 
  error_xenbus:
@@ -512,8 +513,10 @@ static void xen_9pfs_front_changed(struct xenbus_device *dev,
 		break;
 
 	case XenbusStateInitWait:
-		if (!xen_9pfs_front_init(dev))
-			xenbus_switch_state(dev, XenbusStateInitialised);
+		if (dev->state != XenbusStateInitialising)
+			break;
+
+		xen_9pfs_front_init(dev);
 		break;
 
 	case XenbusStateConnected:
-- 
2.43.0