From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 356FAC43219 for ; Tue, 30 Apr 2019 11:47:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 03F5121670 for ; Tue, 30 Apr 2019 11:47:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556624855; bh=ogZCoyPEq2DI32la1nEfKiDDL7SEcnddohJuCQbgvz4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vFfYw9hiKD+Aptss0QlBdilbNF6oOCkFeBr8t3itHgqkRbOgYjjPZs/FAFimTFFLA /ZRXkXmUIgzyuW9Edy7ZrujazOVw1u1mCTCNNBgzRsW2FAoxZZ0rrUVVGgYUCL3VDN BowLmEKl877THNrpFOsiXypSsneV2eLnh/A91v1o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730723AbfD3Lrd (ORCPT ); Tue, 30 Apr 2019 07:47:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:32956 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730698AbfD3Lra (ORCPT ); Tue, 30 Apr 2019 07:47:30 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EB4522054F; Tue, 30 Apr 2019 11:47:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556624849; bh=ogZCoyPEq2DI32la1nEfKiDDL7SEcnddohJuCQbgvz4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Yxb3jdAkr20PqJBVxi/XS/I4ZYo9lmPHO/TD+e+mz8rh0G+SuKq3NAA09mnsLNPX/ iiYORrjncNONoYuoo1DY8/v6WTrVmhi+AdjpbvqrRqg/g0H8uIaaPhUXozMd/J9VqD VWTlF7198V7doRSVwtK8/QbqyWTlyKbEf5Gqd3H4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Maxim Mikityanskiy , Saeed Mahameed Subject: [PATCH 4.19 097/100] net/mlx5e: Fix the max MTU check in case of XDP Date: Tue, 30 Apr 2019 13:39:06 +0200 Message-Id: <20190430113613.412993524@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190430113608.616903219@linuxfoundation.org> References: <20190430113608.616903219@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Maxim Mikityanskiy [ Upstream commit d460c2718906252a2a69bc6f89b537071f792e6e ] MLX5E_XDP_MAX_MTU was calculated incorrectly. It didn't account for NET_IP_ALIGN and MLX5E_HW2SW_MTU, and it also misused MLX5_SKB_FRAG_SZ. This commit fixes the calculations and adds a brief explanation for the formula used. Fixes: a26a5bdf3ee2d ("net/mlx5e: Restrict the combination of large MTU and XDP") Signed-off-by: Maxim Mikityanskiy Signed-off-by: Saeed Mahameed Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 20 ++++++++++++++++++++ drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h | 3 +-- drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 5 +++-- 3 files changed, 24 insertions(+), 4 deletions(-) --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c @@ -33,6 +33,26 @@ #include #include "en/xdp.h" +int mlx5e_xdp_max_mtu(struct mlx5e_params *params) +{ + int hr = NET_IP_ALIGN + XDP_PACKET_HEADROOM; + + /* Let S := SKB_DATA_ALIGN(sizeof(struct skb_shared_info)). + * The condition checked in mlx5e_rx_is_linear_skb is: + * SKB_DATA_ALIGN(sw_mtu + hard_mtu + hr) + S <= PAGE_SIZE (1) + * (Note that hw_mtu == sw_mtu + hard_mtu.) + * What is returned from this function is: + * max_mtu = PAGE_SIZE - S - hr - hard_mtu (2) + * After assigning sw_mtu := max_mtu, the left side of (1) turns to + * SKB_DATA_ALIGN(PAGE_SIZE - S) + S, which is equal to PAGE_SIZE, + * because both PAGE_SIZE and S are already aligned. Any number greater + * than max_mtu would make the left side of (1) greater than PAGE_SIZE, + * so max_mtu is the maximum MTU allowed. + */ + + return MLX5E_HW2SW_MTU(params, SKB_MAX_HEAD(hr)); +} + static inline bool mlx5e_xmit_xdp_buff(struct mlx5e_xdpsq *sq, struct mlx5e_dma_info *di, struct xdp_buff *xdp) --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h @@ -34,12 +34,11 @@ #include "en.h" -#define MLX5E_XDP_MAX_MTU ((int)(PAGE_SIZE - \ - MLX5_SKB_FRAG_SZ(XDP_PACKET_HEADROOM))) #define MLX5E_XDP_MIN_INLINE (ETH_HLEN + VLAN_HLEN) #define MLX5E_XDP_TX_DS_COUNT \ ((sizeof(struct mlx5e_tx_wqe) / MLX5_SEND_WQE_DS) + 1 /* SG DS */) +int mlx5e_xdp_max_mtu(struct mlx5e_params *params); bool mlx5e_xdp_handle(struct mlx5e_rq *rq, struct mlx5e_dma_info *di, void *va, u16 *rx_headroom, u32 *len); bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq); --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -3761,7 +3761,7 @@ int mlx5e_change_mtu(struct net_device * if (params->xdp_prog && !mlx5e_rx_is_linear_skb(priv->mdev, &new_channels.params)) { netdev_err(netdev, "MTU(%d) > %d is not allowed while XDP enabled\n", - new_mtu, MLX5E_XDP_MAX_MTU); + new_mtu, mlx5e_xdp_max_mtu(params)); err = -EINVAL; goto out; } @@ -4227,7 +4227,8 @@ static int mlx5e_xdp_allowed(struct mlx5 if (!mlx5e_rx_is_linear_skb(priv->mdev, &new_channels.params)) { netdev_warn(netdev, "XDP is not allowed with MTU(%d) > %d\n", - new_channels.params.sw_mtu, MLX5E_XDP_MAX_MTU); + new_channels.params.sw_mtu, + mlx5e_xdp_max_mtu(&new_channels.params)); return -EINVAL; }