netdev - Re: [PATCH V7 5/9] PCI/IOV: Enable 10-Bit tag support for PCIe VF devices

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Message-ID: <08b7a9b7-2951-43c3-5e81-3461b6724955@huawei.com>
Date:   Thu, 5 Aug 2021 16:03:58 +0800
From:   Dongdong Liu <liudongdong3@...wei.com>
To:     Bjorn Helgaas <helgaas@...nel.org>
CC:     <hch@...radead.org>, <kw@...ux.com>, <logang@...tatee.com>,
        <leon@...nel.org>, <linux-pci@...r.kernel.org>,
        <rajur@...lsio.com>, <hverkuil-cisco@...all.nl>,
        <linux-media@...r.kernel.org>, <netdev@...r.kernel.org>
Subject: Re: [PATCH V7 5/9] PCI/IOV: Enable 10-Bit tag support for PCIe VF
 devices


On 2021/8/5 7:29, Bjorn Helgaas wrote:
> On Wed, Aug 04, 2021 at 09:47:04PM +0800, Dongdong Liu wrote:
>> Enable VF 10-Bit Tag Requester when it's upstream component support
>> 10-bit Tag Completer.
>
> s/it's/its/
> s/support/supports/
Will fix.
>
> I think "upstream component" here means the PF, doesn't it?  I don't
> think the PF is really an *upstream* component; there's no routing
> like with a switch.
I want to say the switch and root port devices that support 10-Bit
Tag Completer. Sure, VF also needs to have 10-bit Tag Requester
Supported capability.
>
>> Signed-off-by: Dongdong Liu <liudongdong3@...wei.com>
>> Reviewed-by: Christoph Hellwig <hch@....de>
>> ---
>>  drivers/pci/iov.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
>> index dafdc65..0d0bed1 100644
>> --- a/drivers/pci/iov.c
>> +++ b/drivers/pci/iov.c
>> @@ -634,6 +634,10 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
>>
>>  	pci_iov_set_numvfs(dev, nr_virtfn);
>>  	iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
>> +	if ((iov->cap & PCI_SRIOV_CAP_VF_10BIT_TAG_REQ) &&
>> +	    dev->ext_10bit_tag)
>> +		iov->ctrl |= PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN;
>> +
>>  	pci_cfg_access_lock(dev);
>>  	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
>>  	msleep(100);
>> @@ -650,6 +654,8 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
>>
>>  err_pcibios:
>>  	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
>> +	if (iov->ctrl & PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN)
>> +		iov->ctrl &= ~PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN;
>>  	pci_cfg_access_lock(dev);
>>  	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
>>  	ssleep(1);
>> @@ -682,6 +688,8 @@ static void sriov_disable(struct pci_dev *dev)
>>
>>  	sriov_del_vfs(dev);
>>  	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
>> +	if (iov->ctrl & PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN)
>> +		iov->ctrl &= ~PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN;
>
> You can just clear PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN unconditionally,
> can't you?  I know it wouldn't change anything, but removing the "if"
> makes the code prettier.  You could just add it in the existing
> PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE mask.
Will do.

Thanks,
Dongdong
>
>>  	pci_cfg_access_lock(dev);
>>  	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
>>  	ssleep(1);
>> --
>> 2.7.4
>>
> .
>