[PATCH 3.17 31/47] tg3: fix ring init when there are more TX than RX channels

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>

[ Upstream commit a620a6bc1c94c22d6c312892be1e0ae171523125 ]

If TX channels are set to 4 and RX channels are set to less than 4,
using ethtool -L, the driver will try to initialize more RX channels
than it has allocated, causing an oops.

This fix only initializes the RX ring if it has been allocated.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/broadcom/tg3.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -8561,7 +8561,8 @@ static int tg3_init_rings(struct tg3 *tp
 		if (tnapi->rx_rcb)
 			memset(tnapi->rx_rcb, 0, TG3_RX_RCB_RING_BYTES(tp));
 
-		if (tg3_rx_prodring_alloc(tp, &tnapi->prodring)) {
+		if (tnapi->prodring.rx_std &&
+		    tg3_rx_prodring_alloc(tp, &tnapi->prodring)) {
 			tg3_free_rings(tp);
 			return -ENOMEM;
 		}