On Thu, Jul 25, 2013 at 1:10 PM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote: > On Thu, 2013-07-25 at 10:28 +0800, Ming Lei wrote: > >> >> It depends if size of sg buffer(except for last one) in the sg list can be >> divided by usb endpoint's max packet size(512 or 1024), at least there >> is the constraint: >> >> http://git.kernel.org/cgit/linux/kernel/git/gregkh/usb.git/commit/?h=usb-next&id=10e232c597ac757e7f8600649f7e872e86de190f >> >> I am wondering if network stack can meet that. If not, it might be a >> bit difficult >> because lots of USB host controller don't support that, and driver may have >> to support SG and non-SG at the same time for working well on all HCs. > > I do not see the problem. > > If one skb has 2 fragments of 32KB, couldn't they be split into 64 1K > segments by the device driver ? OK, if length of fragments of all SKBs from network stack can always guarantee to be divided by 1024, that is fine, seems I worry about too much, :-) Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
