usbnet: fix alignment for frames with no ethernet header

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: 4ac8904fc170 ("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>

diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index c750cf7c042b004ecfbbce64aefb3d0f1d512c82..304ec6555cd88b3b058b944f6120df3294adb1ca 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 80348b6a864668d0b7535906084bf64f967a1448..d56fe32bf48dea8c617c011d5bd6ddc8d9d5270f 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 a69877734c4eb033b7a7a7f2989e1da241793782..e2ec3582e54937d3818afed3e253440fc23541a0 100644 (file)
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -82,6 +82,7 @@ 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)