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>
This commit is contained in:
Bjørn Mork 2013-01-31 08:36:05 +00:00 committed by David S. Miller
parent 5f1e942cb4
commit bf414b369f

View File

@ -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;