Re: [PATCH 0/4] USB & USBNET: loose DMA SG check and support usbnet DMA SG

Eric Dumazet
2013-07-31T15:25:40Z

On Wed, 2013-07-31 at 18:51 +0800, Ming Lei wrote:
> Hi,
>
> This patchset allows drivers to pass sg buffers which size can't be divided
> by max packet size of endpoint if the host controllers support this kind
> of sg buffers.
>
> Previously we add check[1] on the situation and don't allow these sg buffers
> passed to USB HCD, looks the check is too strict because some applications(such
> as network stack) can't provide this sg buffers which size can be divided by
> max packet size, so this patch looses the check in case that the host controllers
> support it.
>
> Also patch 3/4 implements DMA SG on usbnet driver, and patch 4/4
> enables it on ax88179_178a USB3 NIC, so CPU utilization can be
> decreased much with usbnet DMA SG when the USB3 NIC is attached to
> xHCI controller.

This looks very promising to me, thanks a lot for doing this Ming.

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