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>
This commit is contained in:
Alex Zenla 2024-11-19 21:16:33 +00:00 committed by Greg Kroah-Hartman
parent c375804cf5
commit 91b4763da3

View File

@ -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: