From: Al Viro <viro@ZenIV.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>,
linux-aio@kvack.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] aio: add a iocb refcount
Date: Thu, 2 Aug 2018 00:19:56 +0100 [thread overview]
Message-ID: <20180801231956.GS30522@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20180730071544.23998-3-hch@lst.de>
On Mon, Jul 30, 2018 at 09:15:42AM +0200, Christoph Hellwig wrote:
> This is needed to prevent races caused by the way the ->poll API works.
> To avoid introducing overhead for other users of the iocbs we initialize
> it to zero and only do refcount operations if it is non-zero in the
> completion path.
refcount_t looks like a bad match - you, AFAICS, have count 0 for everything
except poll, while for poll you start with 2. That looks like
if (iocb->shared && test_and_clear_bit(0, &iocb->shared))
return;
kill the sucker
in your iocb_put() and initializing it to 1 in poll. No?
next prev parent reply other threads:[~2018-08-01 23:20 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-30 7:15 aio poll and a new in-kernel poll API V21 (aka 2.0) Christoph Hellwig
2018-07-30 7:15 ` [PATCH 1/4] timerfd: add support for keyed wakeups Christoph Hellwig
2018-07-30 7:15 ` [PATCH 2/4] aio: add a iocb refcount Christoph Hellwig
2018-08-01 23:19 ` Al Viro [this message]
2018-08-02 8:59 ` Christoph Hellwig
2018-07-30 7:15 ` [PATCH 3/4] aio: implement IOCB_CMD_POLL Christoph Hellwig
2018-08-01 23:54 ` Al Viro
2018-08-02 9:00 ` Christoph Hellwig
2018-08-02 0:21 ` Al Viro
2018-08-02 9:22 ` Christoph Hellwig
2018-08-02 16:00 ` Al Viro
2018-08-02 16:08 ` Christoph Hellwig
2018-08-02 16:08 ` Al Viro
2018-08-02 16:16 ` Christoph Hellwig
2018-08-02 21:48 ` Al Viro
2018-07-30 7:15 ` [PATCH 4/4] aio: allow direct aio poll comletions for keyed wakeups Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2018-08-06 8:30 aio poll V22 (aka 2.0) Christoph Hellwig
2018-08-06 8:30 ` [PATCH 2/4] aio: add a iocb refcount Christoph Hellwig
2018-07-26 8:28 aio poll and a new in-kernel poll API V20 (aka 2.0) Christoph Hellwig
2018-07-26 8:29 ` [PATCH 2/4] aio: add a iocb refcount Christoph Hellwig
2018-07-26 11:22 ` Matthew Wilcox
2018-07-26 11:57 ` Christoph Hellwig
2018-07-27 8:31 ` Christoph Hellwig
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