Re: [PATCH] memsw: handle swapaccount kernel parameter correctly

[Michal Hocko]

On Wed 26-01-11 14:06:18, Andrew Morton wrote:
> On Wed, 26 Jan 2011 16:21:58 +0100
> Michal Hocko <mhocko@xxxxxxx> wrote:
> 
> > I am sorry but the patch which added swapaccount parameter is not
> > correct (we have discussed it https://lkml.org/lkml/2010/11/16/103).
> > I didn't get the way how __setup parameters are handled correctly.
> > The patch bellow fixes that.
> > 
> > I am CCing stable as well because the patch got into .37 kernel.
> > 
> > ---
> > >From 144c2e8aed27d82d48217896ee1f58dbaa7f1f84 Mon Sep 17 00:00:00 2001
> > From: Michal Hocko <mhocko@xxxxxxx>
> > Date: Wed, 26 Jan 2011 14:12:41 +0100
> > Subject: [PATCH] memsw: handle swapaccount kernel parameter correctly
> > 
> > __setup based kernel command line parameters handled in
> > obsolete_checksetup provides the parameter value including = (more
> > precisely everything right after the parameter name) so we have to check
> > for =0 resp. =1 here. If no value is given then we get an empty string
> > rather then NULL.
> 
> This doesn't provide a description of the bug which just got fixed.
> 
> From reading the code I think the current behaviour is
> 
> "swapaccount": works OK

Not really because the original test was !s || s="1" but as I am writing
in the commit message we are getting an empty string rather than NULL in
no parameter value case..
So noswapaccount is actually the only thing that is working.

> "noswapaccount": works OK
> "swapaccount=0": doesn't do anything
> "swapaccount=1": doesn't do anything
> 
> but I might be wrong about that.  Please send a changelog update to
> clarify all this.

Sorry for not being specific enough. What about somthing like this:
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