[PATCH 5.4 295/320] net: axienet: limit minimum TX ring size

Greg Kroah-Hartman
2022-01-24T19:51:12Z

From: Robert Hancock <robert.hancock@calian.com>

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>
---
drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- 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

@@ -1223,7 +1224,8 @@ static int axienet_ethtools_set_ringpara
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))