On Tue, Sep 15, 2015 at 12:10:55PM -0500, Will Davis wrote:
> Add helper to convert a struct resource to a peer DMA address.
>
> Signed-off-by: Will Davis <[email protected]>
> ---
> include/linux/pci.h | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index db0cb51..2a9deff 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1508,6 +1508,22 @@ static inline void pci_resource_to_user(const struct
> pci_dev *dev, int bar,
> }
> #endif /* HAVE_ARCH_PCI_RESOURCE_TO_USER */
>
> +#ifdef CONFIG_HAS_DMA_P2P
> +static inline bool pci_resource_to_peer(struct pci_dev *dev,
I'm not really a fan of functions that return bool unless the
function name is obviously a predicate. So in this case, I'd
return 0 or a negative errno.
> + struct pci_dev *peer,
> + struct resource *res,
> + dma_peer_addr_t *peer_addr) {
> + if (pci_peer_traffic_supported(dev, peer)) {
> + struct pci_bus_region region;
> +
> + pcibios_resource_to_bus(dev->bus, ®ion, res);
> + *peer_addr = region.start;
> + return true;
> + }
> +
> + return false;
It's trivial, but I'd structure it like this, which is sort of the
typical "return errors early" pattern, and reduces indentation of the
mainline path:
if (!pci_peer_traffic_supported(dev, peer))
return -EINVAL;
pcibios_resource_to_bus(dev->bus, ®ion, res);
*peer_addr = region.start;
return 0;
> +}
> +#endif /* CONFIG_HAS_DMA_P2P */
>
> /*
> * The world is not perfect and supplies us with broken PCI devices.
> --
> 2.5.1
>
> --
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