Commit bf414b36 authored Jan 31, 2013 by Bjørn Mork Committed by David S. Miller Feb 04, 2013

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>

parent 5f1e942c

drivers/net/usb/usbnet.c

+4 −6

Original line number	Diff line number	Diff line
		@@ -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)) {
		/* 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;
		} else {
		/* cdc_ncm collected packet; waits for more */
		goto not_drop;
		}
		}
		}
		length = skb->len;

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