From: Xiang Zheng <zhengxiang9@huawei.com>
To: <bhelgaas@google.com>
Cc: <zhengxiang9@huawei.com>, <wangxiongfeng2@huawei.com>,
<wanghaibin.wang@huawei.com>, <guoheyi@huawei.com>,
<yebiaoxiang@huawei.com>, <linux-pci@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <willy@infradead.org>,
<rjw@rjwysocki.net>, <tglx@linutronix.de>, <guohanjun@huawei.com>,
<yangyingliang@huawei.com>
Subject: [PATCH] pci: lock the pci_cfg_wait queue for the consistency of data
Date: Mon, 28 Oct 2019 17:18:09 +0800 [thread overview]
Message-ID: <20191028091809.35212-1-zhengxiang9@huawei.com> (raw)
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().
Signed-off-by: Xiang Zheng <zhengxiang9@huawei.com>
Cc: Heyi Guo <guoheyi@huawei.com>
Cc: Biaoxiang Ye <yebiaoxiang@huawei.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
---
drivers/pci/access.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 2fccb5762c76..247bf36e0047 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -207,14 +207,14 @@ static noinline void pci_wait_cfg(struct pci_dev *dev)
{
DECLARE_WAITQUEUE(wait, current);
- __add_wait_queue(&pci_cfg_wait, &wait);
+ add_wait_queue(&pci_cfg_wait, &wait);
do {
set_current_state(TASK_UNINTERRUPTIBLE);
raw_spin_unlock_irq(&pci_lock);
schedule();
raw_spin_lock_irq(&pci_lock);
} while (dev->block_cfg_access);
- __remove_wait_queue(&pci_cfg_wait, &wait);
+ remove_wait_queue(&pci_cfg_wait, &wait);
}
/* Returns 0 on success, negative values indicate error. */
--
2.19.1
next reply other threads:[~2019-10-28 13:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-28 9:18 Xiang Zheng [this message]
2019-10-28 16:30 ` [PATCH] pci: lock the pci_cfg_wait queue for the consistency of data Matthew Wilcox
2019-10-29 3:34 ` Xiang Zheng
2019-11-08 1:12 ` Xiang Zheng
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