usbnet: fix alignment for frames with no ethernet header

[ Upstream commit a4abd7a80addb4a9547f7dfc7812566b60ec505c ]

The qmi_wwan minidriver support a 'raw-ip' mode where frames are
received without any ethernet header. This causes alignment issues
because the skbs allocated by usbnet are "IP aligned".

Fix by allowing minidrivers to disable the additional alignment
offset. This is implemented using a per-device flag, since the same
minidriver also supports 'ethernet' mode.

Fixes: 32f7adf633b9 ("net: qmi_wwan: support "raw IP" mode")
Reported-and-tested-by: Jay Foster <jay@systech.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index f4ed553..81394a4 100644 (file)
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -261,9 +261,11 @@ static void qmi_wwan_netdev_setup(struct net_device *net)
                net->hard_header_len = 0;
                net->addr_len        = 0;
                net->flags           = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
+               set_bit(EVENT_NO_IP_ALIGN, &dev->flags);
                netdev_dbg(net, "mode: raw IP\n");
        } else if (!net->header_ops) { /* don't bother if already set */
                ether_setup(net);
+               clear_bit(EVENT_NO_IP_ALIGN, &dev->flags);
                netdev_dbg(net, "mode: Ethernet\n");
        }
 

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 6510e5c..42baad1 100644 (file)
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -484,7 +484,10 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
                return -ENOLINK;
        }
 
-       skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
+       if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
+               skb = __netdev_alloc_skb(dev->net, size, flags);
+       else
+               skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
        if (!skb) {
                netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
                usbnet_defer_kevent (dev, EVENT_RX_MEMORY);

diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index 9711637..e87a805 100644 (file)
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -81,6 +81,7 @@ struct usbnet {
 #              define EVENT_RX_KILL    10
 #              define EVENT_LINK_CHANGE        11
 #              define EVENT_SET_RX_MODE        12
+#              define EVENT_NO_IP_ALIGN        13
 };
 
 static inline struct usb_driver *driver_of(struct usb_interface *intf)