net: axienet: limit minimum TX ring size

commit 70f5817deddbc6ef3faa35841cab83c280cc653a upstream.

The driver will not work properly if the TX ring size is set to below
MAX_SKB_FRAGS + 1 since it needs to hold at least one full maximally
fragmented packet in the TX ring. Limit setting the ring size to below
this value.

Fixes: 8b09ca823ffb4 ("net: axienet: Make RX/TX ring sizes configurable")
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 478d808..acfd7d5 100644 (file)
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -43,6 +43,7 @@
 /* Descriptors defines for Tx and Rx DMA */
 #define TX_BD_NUM_DEFAULT              64
 #define RX_BD_NUM_DEFAULT              1024
+#define TX_BD_NUM_MIN                  (MAX_SKB_FRAGS + 1)
 #define TX_BD_NUM_MAX                  4096
 #define RX_BD_NUM_MAX                  4096
 
@@ -1373,7 +1374,8 @@ static int axienet_ethtools_set_ringparam(struct net_device *ndev,
        if (ering->rx_pending > RX_BD_NUM_MAX ||
            ering->rx_mini_pending ||
            ering->rx_jumbo_pending ||
-           ering->rx_pending > TX_BD_NUM_MAX)
+           ering->tx_pending < TX_BD_NUM_MIN ||
+           ering->tx_pending > TX_BD_NUM_MAX)
                return -EINVAL;
 
        if (netif_running(ndev))