6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Björn Töpel [ Upstream commit 0160953d8eec75c3c55562158c46442ff1fd410b ] 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. Leave zero unchanged while rounding nonzero ring sizes. The minimum-size check then rejects zero deterministically without changing the established behavior for other values. Fixes: 6cbf18a05c06 ("eth: fbnic: support ring size configuration") Reported-by: Sashiko Link: https://lore.kernel.org/netdev/178971206933.22033.236948278674126701@kernel.org/ Suggested-by: Alexander Duyck Signed-off-by: Björn Töpel Reviewed-by: Joe Damato Link: https://patch.msgid.link/20260918114641.1281172-1-bjorn@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c index 08aed4103323e..d67be9f1a575f 100644 --- a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c +++ b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c @@ -299,6 +299,11 @@ fbnic_get_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring, kernel_ring->hds_thresh = fbn->hds_thresh; } +static u32 fbnic_ring_size_pow2(u32 size) +{ + return size ? roundup_pow_of_two(size) : 0; +} + static void fbnic_set_rings(struct fbnic_net *fbn, struct ethtool_ringparam *ring, struct kernel_ethtool_ringparam *kernel_ring) @@ -320,10 +325,10 @@ 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); + ring->rx_pending = fbnic_ring_size_pow2(ring->rx_pending); + ring->rx_mini_pending = fbnic_ring_size_pow2(ring->rx_mini_pending); + ring->rx_jumbo_pending = fbnic_ring_size_pow2(ring->rx_jumbo_pending); + ring->tx_pending = fbnic_ring_size_pow2(ring->tx_pending); /* These are absolute minimums allowing the device and driver to operate * but not necessarily guarantee reasonable performance. Settings below -- 2.53.0