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From: Jens Axboe <jens.axboe@oracle.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [patch] splice mmap_sem deadlock
Date: Fri, 28 Sep 2007 20:15:14 +0200	[thread overview]
Message-ID: <20070928181513.GB11717@kernel.dk> (raw)
In-Reply-To: <alpine.LFD.0.999.0709281109290.3579@woody.linux-foundation.org>

On Fri, Sep 28 2007, Linus Torvalds wrote:
> 
> 
> On Fri, 28 Sep 2007, Jens Axboe wrote:
> > 
> > It does looks suspicious. It was actually Linus who originally suggested
> > this approach and wrote that comment - Linus?
> 
> Well, it used to be true, long time ago. It probably was still true in the 
> original splice patch back way back when. But yeah, rwsemaphores broke 
> that (very useful) trick in the name of fairness ;(

It actually looks like it was buggy from day 1 there, unfortunately. The
code is from april 2006 and used down_read() even then. So can you apply
Nicks patch, add my

Acked-by: Jens Axboe <jens.axboe@oracle.com>

if you want.

-- 
Jens Axboe

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  reply	other threads:[~2007-09-28 18:15 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-09-28 16:00 Nick Piggin
2007-09-28 17:31 ` Jens Axboe
2007-09-28 18:10   ` Linus Torvalds
2007-09-28 18:15     ` Jens Axboe [this message]
2007-09-28 18:23       ` Linus Torvalds
2007-09-28 19:30         ` Jens Axboe
2007-09-28 20:02           ` Linus Torvalds
2007-09-28 20:08             ` Linus Torvalds
2007-09-29  6:37               ` Jens Axboe
2007-10-01 12:03               ` Jens Axboe
2007-10-01 15:11                 ` Linus Torvalds
2007-10-01 15:45                   ` Balbir Singh
2007-10-01 16:11                     ` Linus Torvalds
2007-10-01 18:19                       ` Balbir Singh
2007-10-01 17:33                   ` Jens Axboe
2007-09-29 13:10             ` Nick Piggin
2007-09-30  6:46               ` Jens Axboe
2007-09-30 12:07                 ` Nick Piggin
2007-09-30 20:05                   ` Jens Axboe
2007-09-30 20:12                     ` Nick Piggin
2007-09-29 13:08     ` Nick Piggin

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