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(such ax xHCI) support this kind of sg buffers.
Previously we added check[1] on the situation and don't allow these sg buffers passed to USB HCD, looks the check is too strict to make use of new feature of new hardware(xHCI) for some applications(such as network stack) which can't provide this kind of sg buffers to usbnet driver, so the patch looses the check in case that the host controller supports it. Patch 3/4 implements DMA SG on usbnet driver, and patch 4/4 uses it on ax88179_178a USB3 NIC for supporting TSO, so both CPU utilization and tx throughput can be improved with TSO and DMA SG in case of the USB NIC is attached to xHCI controller. This patchset depends on both net-next and usb-next tree, so hope David and Greg to figure out one elegent way to merge it. [1], http://git.kernel.org/cgit/linux/kernel/git/gregkh/usb.git/commit/?h=usb-next&id=10e232c597ac757e7f8600649f7e872e86de190f V3: - save 3 lines code for usb_device_no_sg_constraint() as suggested by Alan - fix urb->sg leak in xmit failure path V2: - add missed kfree(urb->sg) in 3/4 - rename no_sg_limit as no_sg_constraint as suggested by Alan V1: - introduce and apply usb_device_no_sg_limit() helper as suggested by Greg - simplify patch 4/4 against Eric Dumazet's patch(ax88179_178a: avoid copy of tx tcp packets) - don't pass usbnet header as sg buffer drivers/net/usb/ax88179_178a.c | 12 +++++++++++ drivers/net/usb/usbnet.c | 45 +++++++++++++++++++++++++++++++++++++--- drivers/usb/core/urb.c | 3 ++- drivers/usb/host/xhci.c | 4 ++++ include/linux/usb.h | 8 ++++++- include/linux/usb/usbnet.h | 1 + 6 files changed, 68 insertions(+), 5 deletions(-) Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
