asix: Fix tx transfer padding for full-speed USB

BugLink: http://bugs.launchpad.net/bugs/1002880

[ Upstream commit 2a5809499e35b53a6044fd34e72b242688b7a862 ]

The asix.c USB Ethernet driver avoids ending a tx transfer with a zero-
length packet by appending a four-byte padding to transfers whose length
is a multiple of maxpacket. However, the hard-coded 512 byte maxpacket
length is valid for high-speed USB only; full-speed USB uses 64 byte
packets.

Signed-off-by: Ingo van Lil <inguin@gmx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/net/usb/asix.c b/drivers/net/usb/asix.c
index 3e33573a249..c44e0e489ba 100644
--- a/drivers/net/usb/asix.c
+++ b/drivers/net/usb/asix.c
@@ -398,7 +398,7 @@ static struct sk_buff *asix_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
         u32 packet_len;
         u32 padbytes = 0xffff0000;
 
-        padlen = ((skb->len + 4) % 512) ? 0 : 4;
+        padlen = ((skb->len + 4) & (dev->maxpacket - 1)) ? 0 : 4;
 
         if ((!skb_cloned(skb)) &&
             ((headroom + tailroom) >= (4 + padlen))) {
@@ -420,7 +420,7 @@ static struct sk_buff *asix_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
         cpu_to_le32s(&packet_len);
         skb_copy_to_linear_data(skb, &packet_len, sizeof(packet_len));
 
-        if ((skb->len % 512) == 0) {
+        if (padlen) {
                 cpu_to_le32s(&padbytes);
                 memcpy(skb_tail_pointer(skb), &padbytes, sizeof(padbytes));
                 skb_put(skb, sizeof(padbytes));