From: "Paul E. McKenney" <paulmck@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Hou Tao <houtao1@huawei.com>, Jens Axboe <axboe@kernel.dk>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
yukuai3@huawei.com, will@kernel.org, peterz@infradead.org
Subject: Re: [PATCH] block: ensure the memory order between bi_private and bi_status
Date: Mon, 19 Jul 2021 11:16:10 -0700 [thread overview]
Message-ID: <20210719181610.GA4397@paulmck-ThinkPad-P17-Gen-1> (raw)
In-Reply-To: <20210715070148.GA8088@lst.de>
On Thu, Jul 15, 2021 at 09:01:48AM +0200, Christoph Hellwig wrote:
> On Thu, Jul 01, 2021 at 07:35:37PM +0800, Hou Tao wrote:
[ . . . ]
> > Fixing it by using smp_load_acquire() & smp_store_release() to guarantee
> > the order between {bio->bi_private|dio->waiter} and {bi_status|bi_blkg}.
> >
> > Fixes: 189ce2b9dcc3 ("block: fast-path for small and simple direct I/O requests")
>
> This obviously does not look broken, but smp_load_acquire /
> smp_store_release is way beyond my paygrade. Adding some CCs.
Huh.
I think that it was back in 2006 when I first told Linus that my goal was
to make memory ordering routine. I clearly have not yet achieved that
goal, even given a lot of help from a lot of people over a lot of years.
Oh well, what is life without an ongoing challenge? ;-)
Thanx, Paul
prev parent reply other threads:[~2021-07-19 18:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-01 11:35 [PATCH] block: ensure the memory order between bi_private and bi_status Hou Tao
2021-07-07 6:29 ` Hou Tao
2021-07-13 1:14 ` Hou Tao
2021-07-15 7:01 ` Christoph Hellwig
2021-07-15 8:13 ` Peter Zijlstra
2021-07-16 9:02 ` Hou Tao
2021-07-16 10:19 ` Peter Zijlstra
2021-07-19 18:09 ` Paul E. McKenney
2021-07-19 18:16 ` Paul E. McKenney [this message]
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