On Thu, Feb 13, 2014 at 04:56:58PM +0000, David Laight wrote: > From: Of Emil Goode > > This patch removes a generic hard_header_len check from the usbnet > > module that is causing dropped packages under certain circumstances > > for devices that send rx packets that cross urb boundaries. > > > > One example is the AX88772B which occasionally send rx packets that > > cross urb boundaries where the remaining partial packet is sent with > > no hardware header. When the buffer with a partial packet is of less > > number of octets than the value of hard_header_len the buffer is > > discarded by the usbnet module. > ... > > diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c > > index d6f64da..955df81 100644 > > --- a/drivers/net/usb/ax88179_178a.c > > +++ b/drivers/net/usb/ax88179_178a.c > > @@ -1118,6 +1118,10 @@ static int ax88179_rx_fixup(struct usbnet *dev, struct sk_buff *skb) > > u16 hdr_off; > > u32 *pkt_hdr; > > > > + /* This check is no longer done by usbnet */ > > + if (skb->len < dev->net->hard_header_len) > > + return 0; > > + > > The ax88179 driver can also receive ethernet frames that cross the > end of rx URB. > It should have the code to save the last fragment (of a urb) until > the next data arrives, and then correctly merge the fragments. > > It is likely that any sub-driver that sets the receive urb length > to a multiple of 1k (rather than leaving it at hard_hdr+mtu) can defrag > rx data that crosses urb boundaries. Yes probably the check is unnecessary to many of the devices but it should be tested by someone who has the hardware. If you have a ax88179 device to test this patch but without the hard_header_len check added to the ax88179_rx_fixup function that would be great. Then we don't need to introduce that check. Best regards, Emil Goode -- 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
