From: Nick Piggin <npiggin@suse.de>
To: Neil Brown <neilb@suse.de>
Cc: Linux Memory Management List <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [rfc][patch] mm: half-fix page tail zeroing on write problem
Date: Fri, 2 Feb 2007 08:21:33 +0100 [thread overview]
Message-ID: <20070202072133.GA26431@wotan.suse.de> (raw)
In-Reply-To: <17858.55858.642522.861130@notabene.brown>
On Fri, Feb 02, 2007 at 05:29:06PM +1100, Neil Brown wrote:
> On Friday February 2, npiggin@suse.de wrote:
> > Hi,
> >
> > For no important reason, I've again looked at those zeroing patches that
> > Neil did a while back. I've always thought that a simple
> > `write(fd, NULL, size)` would cause the same sorts of problems.
>
> Yeh, but who in their right mind would do that???
> Oh, you did :-)
Well that's the test-case. Obviously not many people do it, but that's
all the more reason to be careful about correct behaviour.
> I cannot see why you make a change to fault_in_pages_writeable. Is it
> just for symmetry?
Yes.
> For the rest, it certainly makes sense to return an early -EFAULT if
> you cannot fault in the page.
I think so.
Thanks,
Nick
WARNING: multiple messages have this Message-ID (diff)
From: Nick Piggin <npiggin@suse.de>
To: Neil Brown <neilb@suse.de>
Cc: Linux Memory Management List <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [rfc][patch] mm: half-fix page tail zeroing on write problem
Date: Fri, 2 Feb 2007 08:21:33 +0100 [thread overview]
Message-ID: <20070202072133.GA26431@wotan.suse.de> (raw)
In-Reply-To: <17858.55858.642522.861130@notabene.brown>
On Fri, Feb 02, 2007 at 05:29:06PM +1100, Neil Brown wrote:
> On Friday February 2, npiggin@suse.de wrote:
> > Hi,
> >
> > For no important reason, I've again looked at those zeroing patches that
> > Neil did a while back. I've always thought that a simple
> > `write(fd, NULL, size)` would cause the same sorts of problems.
>
> Yeh, but who in their right mind would do that???
> Oh, you did :-)
Well that's the test-case. Obviously not many people do it, but that's
all the more reason to be careful about correct behaviour.
> I cannot see why you make a change to fault_in_pages_writeable. Is it
> just for symmetry?
Yes.
> For the rest, it certainly makes sense to return an early -EFAULT if
> you cannot fault in the page.
I think so.
Thanks,
Nick
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next prev parent reply other threads:[~2007-02-02 7:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-02 5:51 [rfc][patch] mm: half-fix page tail zeroing on write problem Nick Piggin
2007-02-02 5:51 ` Nick Piggin
2007-02-02 6:29 ` Neil Brown
2007-02-02 6:29 ` Neil Brown
2007-02-02 7:21 ` Nick Piggin [this message]
2007-02-02 7:21 ` Nick Piggin
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