[PATCH] Updates to nfsroot documentation

[PATCH] Updates to nfsroot documentation

[Amos Waterland]

The difference between ip=off and ip=::::::off has been a cause of much
confusion.  Document how each behaves, and do not contradict ourselves
by saying that "off" is the default when in fact "any" is the default
and is descibed as being so lower in the file.

Signed-off-by: Amos Waterland <apw@us.ibm.com>

---

 nfsroot.txt |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/Documentation/nfsroot.txt b/Documentation/nfsroot.txt
index 16a7cae..ac04a1d 100644
--- a/Documentation/nfsroot.txt
+++ b/Documentation/nfsroot.txt
@@ -92,8 +92,11 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
   autoconfiguration.
 
   The <autoconf> parameter can appear alone as the value to the `ip'
-  parameter (without all the ':' characters before) in which case auto-
-  configuration is used.
+  parameter (without all the ':' characters before).  If the value is
+  "ip=off" or "ip=none", no autoconfiguration will take place, otherwise
+  autoconfiguration will take place.  Note that "ip=off" is not the same
+  thing as "ip=::::::off", because in the latter autoconfiguration will take
+  place if any of DHCP, BOOTP or RARP are compiled in the kernel.
 
   <client-ip>	IP address of the client.
 
@@ -142,7 +145,7 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
 		into the kernel will be used, regardless of the value of
 		this option.
 
-                  off or none: don't use autoconfiguration (default)
+                  off or none: don't use autoconfiguration
 		  on or any:   use any protocol available in the kernel
 		  dhcp:        use DHCP
 		  bootp:       use BOOTP

Re: [PATCH] Updates to nfsroot documentation

[Simon Horman]

On Mon, Dec 03, 2007 at 10:43:45PM -0500, Amos Waterland wrote:
> The difference between ip=off and ip=::::::off has been a cause of much
> confusion.  Document how each behaves, and do not contradict ourselves
> by saying that "off" is the default when in fact "any" is the default
> and is descibed as being so lower in the file.

Is that really how it works? If so it sounds a bit silly to me.
Surely it would be desirable for ip=off and ip=::::::off to
do the same thing. Or am I missing the point?

> Signed-off-by: Amos Waterland <apw@us.ibm.com>
> 
> ---
> 
>  nfsroot.txt |    9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/nfsroot.txt b/Documentation/nfsroot.txt
> index 16a7cae..ac04a1d 100644
> --- a/Documentation/nfsroot.txt
> +++ b/Documentation/nfsroot.txt
> @@ -92,8 +92,11 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
>    autoconfiguration.
>  
>    The <autoconf> parameter can appear alone as the value to the `ip'
> -  parameter (without all the ':' characters before) in which case auto-
> -  configuration is used.
> +  parameter (without all the ':' characters before).  If the value is
> +  "ip=off" or "ip=none", no autoconfiguration will take place, otherwise
> +  autoconfiguration will take place.  Note that "ip=off" is not the same
> +  thing as "ip=::::::off", because in the latter autoconfiguration will take
> +  place if any of DHCP, BOOTP or RARP are compiled in the kernel.
>  
>    <client-ip>	IP address of the client.
>  
> @@ -142,7 +145,7 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
>  		into the kernel will be used, regardless of the value of
>  		this option.
>  
> -                  off or none: don't use autoconfiguration (default)
> +                  off or none: don't use autoconfiguration
>  		  on or any:   use any protocol available in the kernel
>  		  dhcp:        use DHCP
>  		  bootp:       use BOOTP

This second fragment seems fine, though perhaps the documentation in
net/ipv4/ipconfig.c, just above ic_proto_name, should also be updated
too.

-- 
Horms

Re: [PATCH] Updates to nfsroot documentation

[Simon Horman]

On Tue, Dec 04, 2007 at 01:24:40PM +0900, Simon Horman wrote:
> On Mon, Dec 03, 2007 at 10:43:45PM -0500, Amos Waterland wrote:
> > The difference between ip=off and ip=::::::off has been a cause of much
> > confusion.  Document how each behaves, and do not contradict ourselves
> > by saying that "off" is the default when in fact "any" is the default
> > and is descibed as being so lower in the file.
> 
> Is that really how it works? If so it sounds a bit silly to me.
> Surely it would be desirable for ip=off and ip=::::::off to
> do the same thing. Or am I missing the point?
> 
> > Signed-off-by: Amos Waterland <apw@us.ibm.com>
> > 
> > ---
> > 
> >  nfsroot.txt |    9 ++++++---
> >  1 file changed, 6 insertions(+), 3 deletions(-)
> > 
> > diff --git a/Documentation/nfsroot.txt b/Documentation/nfsroot.txt
> > index 16a7cae..ac04a1d 100644
> > --- a/Documentation/nfsroot.txt
> > +++ b/Documentation/nfsroot.txt
> > @@ -92,8 +92,11 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
> >    autoconfiguration.
> >  
> >    The <autoconf> parameter can appear alone as the value to the `ip'
> > -  parameter (without all the ':' characters before) in which case auto-
> > -  configuration is used.
> > +  parameter (without all the ':' characters before).  If the value is
> > +  "ip=off" or "ip=none", no autoconfiguration will take place, otherwise
> > +  autoconfiguration will take place.  Note that "ip=off" is not the same
> > +  thing as "ip=::::::off", because in the latter autoconfiguration will take
> > +  place if any of DHCP, BOOTP or RARP are compiled in the kernel.
> >  
> >    <client-ip>	IP address of the client.
> >  
> > @@ -142,7 +145,7 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
> >  		into the kernel will be used, regardless of the value of
> >  		this option.
> >  
> > -                  off or none: don't use autoconfiguration (default)
> > +                  off or none: don't use autoconfiguration
> >  		  on or any:   use any protocol available in the kernel
> >  		  dhcp:        use DHCP
> >  		  bootp:       use BOOTP
> 
> This second fragment seems fine, though perhaps the documentation in
> net/ipv4/ipconfig.c, just above ic_proto_name, should also be updated
> too.

Deleting the documentation in net/ipv4/ipconfig.c might actually
better, as it just duplicates part of what is in Documentation/nfsroot.txt

-- 
Horms

Re: [PATCH] Updates to nfsroot documentation

[Amos Waterland]

On Tue, Dec 04, 2007 at 01:24:40PM +0900, Simon Horman wrote:
> On Mon, Dec 03, 2007 at 10:43:45PM -0500, Amos Waterland wrote:
> > The difference between ip=off and ip=::::::off has been a cause of much
> > confusion.  Document how each behaves, and do not contradict ourselves
> > by saying that "off" is the default when in fact "any" is the default
> > and is descibed as being so lower in the file.
> 
> Is that really how it works? If so it sounds a bit silly to me.
> Surely it would be desirable for ip=off and ip=::::::off to
> do the same thing. Or am I missing the point?

Yes, that is how it works.  Pretty confusing, so I figured I'd better
send in a patch to document it.

In the ip=::::::off case, the code in ip_auto_config() sees that
ic_enable is asserted but that ic_myaddr is NONE and proceeds to do
autoconfiguration.

I'd welcome comments from people on whether we should change how it
works instead of just document it.