From 592fb738d8682bbeabf8acd4c3b207b64266dbc9 Mon Sep 17 00:00:00 2001
From: Alex Zenla <alex@edera.dev>
Date: Tue, 19 Nov 2024 21:16:33 +0000
Subject: [PATCH] 9p/xen: fix init sequence
[ Upstream commit 7ef3ae82a6ebbf4750967d1ce43bcdb7e44ff74b ]
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>
Reviewed-by: Juergen Gross <jgross@suse.com>
Message-ID: <20241119211633.38321-1-alexander@edera.dev>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 dfdbe1ca53387..0304e8a1616d8 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:
--
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