linux-kernel - Re: [PATCH 0/8] PCI/treewide: PCIe Link Width field access cleanup

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Message-ID: <20230912112453.000015f6@Huawei.com>
Date:   Tue, 12 Sep 2023 11:24:53 +0100
From:   Jonathan Cameron <Jonathan.Cameron@...wei.com>
To:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
CC:     <linux-pci@...r.kernel.org>, Bjorn Helgaas <helgaas@...nel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 0/8] PCI/treewide: PCIe Link Width field access cleanup

On Mon, 11 Sep 2023 15:14:53 +0300
Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com> wrote:

> Instead of custom code to extract the PCIe Negotiated and Maximum Link
> Width fields, make the code more obvious using FIELD_GET/PREP().
> 
> Ilpo Järvinen (8):
>   IB/hfi1: Use FIELD_GET() to extract Link Width
>   media: cobalt: Use FIELD_GET() to extract Link Width
>   igb: Use FIELD_GET() to extract Link Width
>   PCI: tegra194: Use FIELD_GET()/FIELD_PREP() with Link Width fields
>   PCI: mvebu: Use FIELD_PREP() with Link Width
>   PCI: Use FIELD_GET() to extract Link Width
>   scsi: esas2r: Use FIELD_GET() to extract Link Width
>   scsi: qla2xxx: Use FIELD_GET() to extract Link Width

I'd like to see this done more generally rather than just
for this one field, but I guess it's a step in the right direction.
I'm particularly in favour of the cases where 4 was used
rather than the define.

> 
>  drivers/infiniband/hw/hfi1/pcie.c          |  5 +++--

As an example, immediately above the link width code is link
speed code.  Using FIELD_GET there as well would avoid people
having to 'know' that field is at 0 shift.

So for what you have 
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
but I'd like to see this taken further.

A few minor comments in some of the individual patches.

>  drivers/media/pci/cobalt/cobalt-driver.c   | 11 ++++++-----
>  drivers/net/ethernet/intel/igb/e1000_mac.c |  6 +++---
>  drivers/pci/controller/dwc/pcie-tegra194.c |  9 ++++-----
>  drivers/pci/controller/pci-mvebu.c         |  2 +-
>  drivers/pci/pci-sysfs.c                    |  5 ++---
>  drivers/pci/pci.c                          |  6 +++---
>  drivers/scsi/esas2r/esas2r_ioctl.c         |  8 ++++----
>  drivers/scsi/qla2xxx/qla_os.c              |  3 ++-
>  9 files changed, 28 insertions(+), 27 deletions(-)
>