Subject: Re: [PATCH 2/2] PCI/MSI: Remove arch_msi_check_device()

From: Bjorn Helgaas <[email-masked]>
Date: Wed, 16 Jul 2014 16:20:24 -0600

On Sat, Jul 12, 2014 at 01:21:08PM +0200, Alexander Gordeev wrote:
> There are no archs that override arch_msi_check_device()
> hook. Remove it as it is completely redundant.
> 
> If an arch would need to check MSI/MSI-X possibility for a
> device it should make it within arch_setup_msi_irqs() hook.
> 
> Cc: [email-masked]
> Cc: [email-masked]
> Signed-off-by: Alexander Gordeev <[email-masked]>
> ---
>  drivers/pci/msi.c   |   49 +++++++++++++------------------------------------
>  include/linux/msi.h |    3 ---
>  2 files changed, 13 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index 13f3d30..19ac058 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -56,16 +56,6 @@ void __weak arch_teardown_msi_irq(unsigned int irq)
>  	chip->teardown_irq(chip, irq);
>  }
>  
> -int __weak arch_msi_check_device(struct pci_dev *dev, int nvec, int type)
> -{
> -	struct msi_chip *chip = dev->bus->msi;
> -
> -	if (!chip || !chip->check_device)
> -		return 0;
> -
> -	return chip->check_device(chip, dev, nvec, type);
> -}
> -
>  int __weak arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>  {
>  	struct msi_desc *entry;
> @@ -809,22 +799,23 @@ out_free:
>  }
>  
>  /**
> - * pci_msi_check_device - check whether MSI may be enabled on a device
> + * msi_check_device - check whether MSI may be enabled on a device
>   * @dev: pointer to the pci_dev data structure of MSI device function
>   * @nvec: how many MSIs have been requested ?
> - * @type: are we checking for MSI or MSI-X ?
>   *
>   * Look at global flags, the device itself, and its parent buses
>   * to determine if MSI/-X are supported for the device. If MSI/-X is
>   * supported return 0, else return an error code.
>   **/
> -static int pci_msi_check_device(struct pci_dev *dev, int nvec, int type)
> +static int msi_check_device(struct pci_dev *dev, int nvec)

I think "check_device" is a terrible name because it really doesn't
give a clue about what it's doing or what the return value means.
Since you're removing the external usage (arch_msi_check_device) and
this one is static, this would be a good time to fix it.  Maybe
"pci_msi_supported()" or something?

I *love* the idea of getting rid of this much code!

Bjorn