From: Matthew Wilcox <willy@infradead.org>
To: Xiang Zheng <zhengxiang9@huawei.com>
Cc: bhelgaas@google.com, wangxiongfeng2@huawei.com,
wanghaibin.wang@huawei.com, guoheyi@huawei.com,
yebiaoxiang@huawei.com, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org, rjw@rjwysocki.net,
tglx@linutronix.de, guohanjun@huawei.com,
yangyingliang@huawei.com
Subject: Re: [PATCH] pci: lock the pci_cfg_wait queue for the consistency of data
Date: Mon, 28 Oct 2019 09:30:41 -0700 [thread overview]
Message-ID: <20191028163041.GA8257@bombadil.infradead.org> (raw)
In-Reply-To: <20191028091809.35212-1-zhengxiang9@huawei.com>
On Mon, Oct 28, 2019 at 05:18:09PM +0800, Xiang Zheng wrote:
> Commit "7ea7e98fd8d0" suggests that the "pci_lock" is sufficient,
> and all the callers of pci_wait_cfg() are wrapped with the "pci_lock".
>
> However, since the commit "cdcb33f98244" merged, the accesses to
> the pci_cfg_wait queue are not safe anymore. A "pci_lock" is
> insufficient and we need to hold an additional queue lock while
> read/write the wait queue.
>
> So let's use the add_wait_queue()/remove_wait_queue() instead of
> __add_wait_queue()/__remove_wait_queue().
As I said earlier, this reintroduces the deadlock addressed by
cdcb33f9824429a926b971bf041a6cec238f91ff
next prev parent reply other threads:[~2019-10-28 16:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-28 9:18 [PATCH] pci: lock the pci_cfg_wait queue for the consistency of data Xiang Zheng
2019-10-28 16:30 ` Matthew Wilcox [this message]
2019-10-29 3:34 ` Xiang Zheng
2019-11-08 1:12 ` Xiang Zheng
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