netdev - Re: [PATCH 1/3] PCI: introduce a device-managed version of pci_set

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Date:   Mon, 11 Dec 2017 17:00:25 -0600
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Heiner Kallweit <hkallweit1@...il.com>
Cc:     Realtek linux nic maintainers <nic_swsd@...ltek.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>
Subject: Re: [PATCH 1/3] PCI: introduce a device-managed version of
 pci_set_mwi

On Sun, Dec 10, 2017 at 12:43:48AM +0100, Heiner Kallweit wrote:
> Introduce a device-managed version of pci_set_mwi. First user is the
> Realtek r8169 driver.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>

With the subject and changelog as follows and the code reordering below,

  PCI: Add pcim_set_mwi(), a device-managed pci_set_mwi()

  Add pcim_set_mwi(), a device-managed version of pci_set_mwi(). First user
  is the Realtek r8169 driver.

Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>

With these changes, feel free to merge with the series via the netdev
tree.

> ---
>  drivers/pci/pci.c   | 29 +++++++++++++++++++++++++++++
>  include/linux/pci.h |  1 +
>  2 files changed, 30 insertions(+)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 4a7c6864f..fc57c378d 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -1458,6 +1458,7 @@ struct pci_devres {
>  	unsigned int pinned:1;
>  	unsigned int orig_intx:1;
>  	unsigned int restore_intx:1;
> +	unsigned int mwi:1;
>  	u32 region_mask;
>  };
>  
> @@ -1476,6 +1477,9 @@ static void pcim_release(struct device *gendev, void *res)
>  		if (this->region_mask & (1 << i))
>  			pci_release_region(dev, i);
>  
> +	if (this->mwi)
> +		pci_clear_mwi(dev);
> +
>  	if (this->restore_intx)
>  		pci_intx(dev, this->orig_intx);
>  
> @@ -3760,6 +3764,31 @@ int pci_set_mwi(struct pci_dev *dev)
>  }
>  EXPORT_SYMBOL(pci_set_mwi);
>  
> +/**
> + * pcim_set_mwi - Managed pci_set_mwi()
> + * @dev: the PCI device for which MWI is enabled
> + *
> + * Managed pci_set_mwi().
> + *
> + * RETURNS: An appropriate -ERRNO error value on error, or zero for success.

> + */
> +int pcim_set_mwi(struct pci_dev *dev)
> +{
> +	struct pci_devres *dr;
> +	int ret;
> +
> +	ret = pci_set_mwi(dev);
> +	if (ret)
> +		return ret;
> +
> +	dr = find_pci_dr(dev);
> +	if (dr)
> +		dr->mwi = 1;
> +
> +	return 0;

I would rather look up the pci_devres first, e.g.,

  dr = find_pci_dr(dev);
  if (!dr)
    return -ENOMEM;

  dr->mwi = 1;
  return pci_set_mwi(dev);

That way we won't enable MWI and be unable to disable it at release-time.

> +}
> +EXPORT_SYMBOL(pcim_set_mwi);
> +
>  /**
>   * pci_try_set_mwi - enables memory-write-invalidate PCI transaction
>   * @dev: the PCI device for which MWI is enabled
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 978aad784..0a7ac863a 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1064,6 +1064,7 @@ int pci_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state);
>  int pci_set_cacheline_size(struct pci_dev *dev);
>  #define HAVE_PCI_SET_MWI
>  int __must_check pci_set_mwi(struct pci_dev *dev);
> +int __must_check pcim_set_mwi(struct pci_dev *dev);
>  int pci_try_set_mwi(struct pci_dev *dev);
>  void pci_clear_mwi(struct pci_dev *dev);
>  void pci_intx(struct pci_dev *dev, int enable);
> -- 
> 2.15.1
> 
>