linux-kernel - Re: [PATCH v2 5/7] PCI: Wait 1 second between disabling VFs and clearing NumVFs

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Message-ID: <20151030051458.GD5119@richards-mbp.cn.ibm.com>
Date:	Fri, 30 Oct 2015 13:14:58 +0800
From:	Wei Yang <weiyang@...ux.vnet.ibm.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
Cc:	Alexander Duyck <aduyck@...antis.com>, linux-pci@...r.kernel.org,
	Ethan Zhao <ethan.zhao@...cle.com>,
	Wei Yang <weiyang@...ux.vnet.ibm.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 5/7] PCI: Wait 1 second between disabling VFs and
 clearing NumVFs

On Thu, Oct 29, 2015 at 05:23:22PM -0500, Bjorn Helgaas wrote:
>From: Alexander Duyck <aduyck@...antis.com>
>
>Per sec 3.3.3.1 of the SR-IOV spec, r1.1, we must allow 1.0s after clearing
>VF Enable before reading any field in the SR-IOV Extended Capability.
>
>Wait 1 second before calling pci_iov_set_numvfs(), which reads
>PCI_SRIOV_VF_OFFSET and PCI_SRIOV_VF_STRIDE after it sets PCI_SRIOV_NUM_VF.
>
>[bhelgaas: split to separate patch for reviewability, add spec reference]
>Signed-off-by: Alexander Duyck <aduyck@...antis.com>
>Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
>---
> drivers/pci/iov.c |    2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
>index fada98d..24428d5 100644
>--- a/drivers/pci/iov.c
>+++ b/drivers/pci/iov.c
>@@ -339,13 +339,13 @@ failed:
> 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
> 	pci_cfg_access_lock(dev);
> 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
>-	pci_iov_set_numvfs(dev, 0);
> 	ssleep(1);
> 	pci_cfg_access_unlock(dev);
>
> 	if (iov->link != dev->devfn)
> 		sysfs_remove_link(&dev->dev.kobj, "dep_link");
>
>+	pci_iov_set_numvfs(dev, 0);

One small question, any specific reason put it here instead of just after
sleep()?

> 	return rc;
> }
>

-- 
Richard Yang
Help you, Help me

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