From: Al Viro <viro@zeniv.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
aaw@google.com
Subject: Re: [PATCH 2/2] exec: open code copy_string_kernel
Date: Fri, 1 May 2020 22:43:55 +0100 [thread overview]
Message-ID: <20200501214355.GP23230@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200501192639.GA25896@lst.de>
On Fri, May 01, 2020 at 09:26:39PM +0200, Christoph Hellwig wrote:
> On Fri, May 01, 2020 at 01:50:49PM +0100, Al Viro wrote:
> > On Fri, May 01, 2020 at 12:41:05PM +0200, Christoph Hellwig 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 can live with that... BTW, why do we bother with flush_cache_page() (by
> > way of get_arg_page()) here and in copy_strings()? How could *anything*
> > have accessed that page by its address in new mm - what are we trying to
> > flush here?
>
> s/get_arg_page/flush_arg_page/ ?
of course - sorry...
> No idea, what the use case is, but this comes from:
>
> commit b6a2fea39318e43fee84fa7b0b90d68bed92d2ba
> Author: Ollie Wild <aaw@google.com>
> Date: Thu Jul 19 01:48:16 2007 -0700
>
> mm: variable length argument support
I know. And it comes with no explanations in there ;-/ AFAICS, back then
the situation hadn't been any different - mm we are inserting the arg pages
into is not active, so there shouldn't be anything in anyone's cache for
that virtual address in that vma...
next prev parent reply other threads:[~2020-05-01 21:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-01 10:41 remove set_fs from copy_strings_kernel Christoph Hellwig
2020-05-01 10:41 ` [PATCH 1/2] exec: simplify the copy_strings_kernel calling convention Christoph Hellwig
2020-05-01 10:41 ` [PATCH 2/2] exec: open code copy_string_kernel Christoph Hellwig
2020-05-01 12:50 ` Al Viro
2020-05-01 19:26 ` Christoph Hellwig
2020-05-01 21:43 ` Al Viro [this message]
2020-05-01 21:19 ` Andrew Morton
2020-05-01 21:30 ` Al Viro
2020-05-01 21:40 ` Andrew Morton
2020-05-01 22:04 ` Al Viro
2020-05-02 6:23 ` Christoph Hellwig
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