net: ipa: certain dropped packets aren't accounted for

If an RX endpoint receives packets containing status headers, and a
packet in the buffer is not dropped, ipa_endpoint_skb_copy() is
responsible for wrapping the packet data in an SKB and forwarding it
to ipa_modem_skb_rx() for further processing.

If ipa_endpoint_skb_copy() gets a null pointer from build_skb(), it
just returns early.  But in the process it doesn't record that as a
dropped packet in the network device statistics.

Instead, call ipa_modem_skb_rx() whether or not the SKB pointer is
NULL; that function ensures the statistics are properly updated.

Fixes: 1b65bbcc ("net: ipa: skip SKB copy if no netdev")
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipa/ipa_endpoint.c

@@ -1150,13 +1150,12 @@ static void ipa_endpoint_skb_copy(struct ipa_endpoint *endpoint,
 		return;
 
 	skb = __dev_alloc_skb(len, GFP_ATOMIC);
-	if (!skb)
-		return;
-
+	if (skb) {
 		/* Copy the data into the socket buffer and receive it */
 		skb_put(skb, len);
 		memcpy(skb->data, data, len);
 		skb->truesize += extra;
+	}
 
 	ipa_modem_skb_rx(endpoint->netdev, skb);
 }