From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Jackson <Ian.Jackson@eu.citrix.com>
Subject: Re: [PATCH 2/2] Load gntdev and evtchn if they're
	modular. [and 1 more messages]
Date: Tue, 30 Aug 2011 17:46:06 +0100
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To: Olaf Hering <olaf@aepfle.de>, Jeremy Fitzhardinge <jeremy@goop.org>
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Jeremy Fitzhardinge writes ("[Xen-devel] [PATCH 2/2] Load gntdev and evtchn if they're modular."):
> -if [ "x$1" = xstart -a -d /proc/xen -a \
> -    ! -f /proc/xen/capabilities ] && \
> -    ! grep -qw '^xenfs' /proc/mounts; then
> -	mount -t xenfs xenfs /proc/xen
> +[ -d /proc/xen ] || exit 0	# Xen not present; exit quietly
> +
> +if [ "x$1" = xstart ]; then
> +	# Mount /proc/xen if needed
> +	[ -f /proc/xen/capabilities ] || mount -t xenfs xenfs /proc/xen
> +
> +	# Make sure evtchn and gntdev are loaded if present
> +	grep -q "xen/evtchn" /proc/misc || modprobe xen-evtchn
> +	grep -q "xen/gntdev" /proc/misc || modprobe xen-gntdev
>  fi

I'd be inclined to accept this although because I didn't like your
previous patch, it doesn't apply.

Olaf Hering writes ("[Xen-devel] [PATCH v2] hotplug: update xencommons script to run only when needed"):
> +# not running in Xen dom0 or domU
> +if ! test -d /proc/xen ; then
> +	exit 0
> +fi

This part is fine.

> +# mount xenfs in dom0 or domU with a pv_ops kernel
>  if test "x$1" = xstart && \
> -     test -d /proc/xen && \

Fine.

>     ! test -f /proc/xen/capabilities && \
> -   ! grep '^xenfs ' /proc/mounts >/dev/null;
> +   ! grep -q '^xenfs ' /proc/mounts ;
>  then
>  	mount -t xenfs xenfs /proc/xen
>  fi

As I said to Jeremy, I'm not sure I want style changes.  I'm not
convinced of the huge usefulness of this one either.

> +# run this script only in dom0:
> +# no capabilities file in xenlinux kernel
> +if ! test -f /proc/xen/capabilities ; then
> +	exit 0
> +fi
> +# empty capabilities file in pv_ops kernel
>  if ! grep -q "control_d" /proc/xen/capabilities ; then
>  	exit 0
>  fi

If /proc/xen/capabilities is missing, what does it mean ?  Do domU
kernels really not provide that file ?  Also these two ifs would be
better combined.

Ian.