[PATCH net] eth: fbnic: Avoid rounding zero ring sizes

[Björn Töpel]

roundup_pow_of_two() is undefined for zero. ethtool permits a zero ring
size to reach the driver, where the minimum-size check should reject it.

Validate the requested sizes before rounding them so zero is rejected
deterministically.

Fixes: 6cbf18a05c06 ("eth: fbnic: support ring size configuration")
Suggested-by: Alexander Duyck <alexanderduyck@xxxxxx>
Signed-off-by: Björn Töpel <bjorn@xxxxxxxxxx>
---
 drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
index 0e47088ec44b..8954fcd08cb3 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
@@ -334,11 +334,6 @@ fbnic_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring,
 	struct fbnic_net *clone;
 	int err;
 
-	ring->rx_pending	= roundup_pow_of_two(ring->rx_pending);
-	ring->rx_mini_pending	= roundup_pow_of_two(ring->rx_mini_pending);
-	ring->rx_jumbo_pending	= roundup_pow_of_two(ring->rx_jumbo_pending);
-	ring->tx_pending	= roundup_pow_of_two(ring->tx_pending);
-
 	/* These are absolute minimums allowing the device and driver to operate
 	 * but not necessarily guarantee reasonable performance. Settings below
 	 * Rx queue size of 128 and BDQs smaller than 64 are likely suboptimal
@@ -368,6 +363,11 @@ fbnic_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring,
 		return -EINVAL;
 	}
 
+	ring->rx_pending	= roundup_pow_of_two(ring->rx_pending);
+	ring->rx_mini_pending	= roundup_pow_of_two(ring->rx_mini_pending);
+	ring->rx_jumbo_pending	= roundup_pow_of_two(ring->rx_jumbo_pending);
+	ring->tx_pending	= roundup_pow_of_two(ring->tx_pending);
+
 	if (!netif_running(netdev)) {
 		fbnic_set_rings(fbn, ring, kernel_ring);
 		return 0;

base-commit: 18a6fe05fb6e18de29fa90d388bb34044114b3d8
-- 
2.55.0