From: Jakub Kicinski Date: Wed, 12 Apr 2023 01:50:38 +0000 (-0700) Subject: mlx4: use READ_ONCE/WRITE_ONCE for ring indexes X-Git-Tag: v6.4-rc1~77^2~120^2 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=9a714997386ba110154dc444cdd0279f966151b2;p=linux-block.git mlx4: use READ_ONCE/WRITE_ONCE for ring indexes Eric points out that we should make sure that ring index updates are wrapped in the appropriate READ_ONCE/WRITE_ONCE macros. Suggested-by: Eric Dumazet Reviewed-by: Eric Dumazet Reviewed-by: Jesse Brandeburg Signed-off-by: Jakub Kicinski Reviewed-by: Tariq Toukan Signed-off-by: Paolo Abeni --- diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index 2f79378fbf6e..65cb63f6c465 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -228,7 +228,9 @@ void mlx4_en_deactivate_tx_ring(struct mlx4_en_priv *priv, static inline bool mlx4_en_is_tx_ring_full(struct mlx4_en_tx_ring *ring) { - return ring->prod - ring->cons > ring->full_size; + u32 used = READ_ONCE(ring->prod) - READ_ONCE(ring->cons); + + return used > ring->full_size; } static void mlx4_en_stamp_wqe(struct mlx4_en_priv *priv, @@ -1083,7 +1085,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) op_own |= cpu_to_be32(MLX4_WQE_CTRL_IIP); } - ring->prod += nr_txbb; + WRITE_ONCE(ring->prod, ring->prod + nr_txbb); /* If we used a bounce buffer then copy descriptor back into place */ if (unlikely(bounce)) @@ -1214,7 +1216,7 @@ netdev_tx_t mlx4_en_xmit_frame(struct mlx4_en_rx_ring *rx_ring, rx_ring->xdp_tx++; - ring->prod += MLX4_EN_XDP_TX_NRTXBB; + WRITE_ONCE(ring->prod, ring->prod + MLX4_EN_XDP_TX_NRTXBB); /* Ensure new descriptor hits memory * before setting ownership of this descriptor to HW