Xen devel - Aug 2011 - [PATCH 2/2] Load gntdev and evtchn if they''re modular.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>


diff -r cfb49fe940fd -r 81f75ed45ec2 tools/hotplug/Linux/init.d/xencommons
--- a/tools/hotplug/Linux/init.d/xencommons	Tue Aug 16 16:56:16 2011 -0700
+++ b/tools/hotplug/Linux/init.d/xencommons	Tue Aug 16 17:05:18 2011 -0700
@@ -29,12 +29,18 @@
 XENCONSOLED_PIDFILE=/var/run/xenconsoled.pid
 shopt -s extglob
 
-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
 
+# Done here if this isn''t a control domain
 if ! grep -q "control_d" /proc/xen/capabilities ; then
 	exit 0
 fi




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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.

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On Tue, Aug 30, Ian Jackson wrote:
> > +# 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 ?
It means a domU with xenlinux PV drivers loaded, in that case the script
has to do nothing.
> kernels really not provide that file ?  Also these two ifs would be
> better combined.
How would that look like? First the file is not there, so grep will
print an error - thats what my patch tries to fix.
Second the file is there and may indicate a dom0.

Olaf

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Olaf Hering writes ("Re: [Xen-devel] [PATCH 2/2] Load gntdev and evtchn if
they''re modular. [and 1 more messages]"):
> How would that look like? First the file is not there, so grep will
> print an error - thats what my patch tries to fix.
If you write
   false && true
the shell does not execute true.

Ian.

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