net: usbnet: fix tx_dropped statistics

It is normal for minidrivers accumulating frames to return NULL
from their tx_fixup function. We do not want to count this as a
drop, or log any debug messages.  A different exit path is
therefore chosen for such drivers, skipping the debug message
and the tx_dropped increment.

The test for accumulating drivers was however completely bogus,
making the exit path selection depend on whether the user had
enabled tx_err logging or not. This would arbitrarily mess up
accounting for both accumulating and non-accumulating minidrivers,
and would result in unwanted debug messages for the accumulating
drivers.

Fix by testing for FLAG_MULTI_PACKET instead, which probably was
the intention from the beginning.  This usage match the documented
behaviour of this flag:

 Indicates to usbnet, that USB driver accumulates multiple IP packets.
 Affects statistic (counters) and short packet handling.

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 97783772572637c5f632e3563b728aa512a679e5..5e33606c136639f9b9ad7cf38e7ed8c48c7a51eb 100644 (file)
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1125,13 +1125,11 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
        if (info->tx_fixup) {
                skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
                if (!skb) {
-                       if (netif_msg_tx_err(dev)) {
-                               netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
-                               goto drop;
-                       } else {
-                               /* cdc_ncm collected packet; waits for more */
+                       /* packet collected; minidriver waiting for more */
+                       if (info->flags & FLAG_MULTI_PACKET)
                                goto not_drop;
-                       }
+                       netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
+                       goto drop;
                }
        }
        length = skb->len;