From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Jones <drjones@redhat.com>
Subject: question regarding 2.6.18 backport
Date: Tue, 19 Feb 2013 14:51:05 +0100
Message-ID: <20130219145105.6274e9ea@hawk.usersys.redhat.com>
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To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: xen-devel@lists.xensource.com
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Hi Ian,

I believe there's a problem with the 2.6.18 reference tree backport of
48856286b64e: "xen/netback: shutdown the ring if it contains garbage",
which is c/s 1219. While the version in Linus' tree should be fine,
as xen_netbk_tx_action runs in a kthread, the 2.6.18 version needs
something different. In 2.6.18 net_tx_action is a tasklet, thus calling
xenvif_carrier_off from it is problematic due to needing the rtnl
mutex. A proposal I have that I haven't tried yet is for
netbk_fatal_tx_err to schedule xenvif_carrier_off in a workqueue. This
is a bit ugly though since the main point of xenvif_carrier_off is to
queue linkwatch work. I'm wondering if you or anyone else have other
suggestions.

Thanks,
Drew