linux-kernel - Re: [PATCH 2/2] exec: open code copy_string

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Message-Id: <20200501144013.be5bf036ab7f2d2303676bce@linux-foundation.org>
Date:   Fri, 1 May 2020 14:40:13 -0700
From:   Andrew Morton <akpm@...ux-foundation.org>
To:     Al Viro <viro@...iv.linux.org.uk>
Cc:     Christoph Hellwig <hch@....de>, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] exec: open code copy_string_kernel

On Fri, 1 May 2020 22:30:48 +0100 Al Viro <viro@...iv.linux.org.uk> wrote:

> On Fri, May 01, 2020 at 02:19:03PM -0700, Andrew Morton wrote:
> > On Fri,  1 May 2020 12:41:05 +0200 Christoph Hellwig <hch@....de> wrote:
> > 
> > > Currently copy_string_kernel is just a wrapper around copy_strings that
> > > simplifies the calling conventions and uses set_fs to allow passing a
> > > kernel pointer.  But due to the fact the we only need to handle a single
> > > kernel argument pointer, the logic can be sigificantly simplified while
> > > getting rid of the set_fs.
> > > 
> > 
> > I don't get why this is better?  copy_strings() is still there and
> > won't be going away - what's wrong with simply reusing it in this
> > fashion?
> > 
> > I guess set_fs() is a bit hacky, but there's the benefit of not having
> > to maintain two largely similar bits of code?
> 
> Killing set_fs() would be a very good thing...

Why is that?  And is there a project afoot to do this?