From: Esben Haabendal <esben@geanix.com>
Date: Tue, 30 Apr 2019 07:17:56 +0000 (+0200)
Subject: net: ll_temac: Fix bug causing buffer descriptor overrun
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2c9938e738a273ba315679781a9990c7d3b1831b;p=linux.git

net: ll_temac: Fix bug causing buffer descriptor overrun

As we are actually using a BD for both the skb and each frag contained in
it, the oldest TX BD would be overwritten when there was exactly one BD
less than needed.

Signed-off-by: Esben Haabendal <esben@geanix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c
index 7e42746f2292d..68375655e61b7 100644
--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -743,7 +743,7 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	start_p = lp->tx_bd_p + sizeof(*lp->tx_bd_v) * lp->tx_bd_tail;
 	cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
 
-	if (temac_check_tx_bd_space(lp, num_frag)) {
+	if (temac_check_tx_bd_space(lp, num_frag + 1)) {
 		if (!netif_queue_stopped(ndev))
 			netif_stop_queue(ndev);
 		return NETDEV_TX_BUSY;