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=-6.0 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 EF7D6C43381 for ; Mon, 25 Feb 2019 21:34:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BED7220578 for ; Mon, 25 Feb 2019 21:34:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551130458; bh=MgpIExTFyEDj+4qqdEctvPVj9nsrFADLJOZSpW7oOX8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=LIu6eIVaWWtYLUtBZaKWMRciaQOQsL7FO0awJR8yYfmW7ZrfZRB5E4CalvHIwNJd/ 2hJUz/vIsSyXrIEIOVcpfI4Vg0kUZDaNdUdszWvNOeN0QFlsnqKQeqO0kKOZ4drXbV 1mhHmAx5zZdhv9fX6WWoyGlSRdtPBYU9ZwUEMfHQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732802AbfBYVeR (ORCPT ); Mon, 25 Feb 2019 16:34:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:40494 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732788AbfBYVeP (ORCPT ); Mon, 25 Feb 2019 16:34:15 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 9497A20578; Mon, 25 Feb 2019 21:34:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551130454; bh=MgpIExTFyEDj+4qqdEctvPVj9nsrFADLJOZSpW7oOX8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LiompUkMWt6DK2kH7+3C8f/U/sOjJ1QYmdYya+1U+8lp6e+4ixps2TrqmTQUwV1rL p6gOUyiJL1uUa8vi3Ig+egeBBAT7g801aPWfL9uciyBmAcV6LEuEPnW/zSofGbQepX BIyseStEkAkfddXRcVmmaDtUAeUrj9s9+4Bads+A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Saeed Mahameed , Tariq Toukan , "David S. Miller" Subject: [PATCH 4.20 126/183] net/mlx4_en: Force CHECKSUM_NONE for short ethernet frames Date: Mon, 25 Feb 2019 22:11:39 +0100 Message-Id: <20190225195115.958152604@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190225195054.748060397@linuxfoundation.org> References: <20190225195054.748060397@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Saeed Mahameed [ Upstream commit 29dded89e80e3fff61efb34f07a8a3fba3ea146d ] When an ethernet frame is padded to meet the minimum ethernet frame size, the padding octets are not covered by the hardware checksum. Fortunately the padding octets are usually zero's, which don't affect checksum. However, it is not guaranteed. For example, switches might choose to make other use of these octets. This repeatedly causes kernel hardware checksum fault. Prior to the cited commit below, skb checksum was forced to be CHECKSUM_NONE when padding is detected. After it, we need to keep skb->csum updated. However, fixing up CHECKSUM_COMPLETE requires to verify and parse IP headers, it does not worth the effort as the packets are so small that CHECKSUM_COMPLETE has no significant advantage. Future work: when reporting checksum complete is not an option for IP non-TCP/UDP packets, we can actually fallback to report checksum unnecessary, by looking at cqe IPOK bit. Fixes: 88078d98d1bb ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends") Cc: Eric Dumazet Signed-off-by: Saeed Mahameed Signed-off-by: Tariq Toukan Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/mellanox/mlx4/en_rx.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c @@ -620,6 +620,8 @@ static int get_fixed_ipv6_csum(__wsum hw } #endif +#define short_frame(size) ((size) <= ETH_ZLEN + ETH_FCS_LEN) + /* We reach this function only after checking that any of * the (IPv4 | IPv6) bits are set in cqe->status. */ @@ -627,9 +629,20 @@ static int check_csum(struct mlx4_cqe *c netdev_features_t dev_features) { __wsum hw_checksum = 0; + void *hdr; - void *hdr = (u8 *)va + sizeof(struct ethhdr); + /* CQE csum doesn't cover padding octets in short ethernet + * frames. And the pad field is appended prior to calculating + * and appending the FCS field. + * + * Detecting these padded frames requires to verify and parse + * IP headers, so we simply force all those small frames to skip + * checksum complete. + */ + if (short_frame(skb->len)) + return -EINVAL; + hdr = (u8 *)va + sizeof(struct ethhdr); hw_checksum = csum_unfold((__force __sum16)cqe->checksum); if (cqe->vlan_my_qpn & cpu_to_be32(MLX4_CQE_CVLAN_PRESENT_MASK) && @@ -822,6 +835,11 @@ xdp_drop_no_cnt: skb_record_rx_queue(skb, cq_ring); if (likely(dev->features & NETIF_F_RXCSUM)) { + /* TODO: For IP non TCP/UDP packets when csum complete is + * not an option (not supported or any other reason) we can + * actually check cqe IPOK status bit and report + * CHECKSUM_UNNECESSARY rather than CHECKSUM_NONE + */ if ((cqe->status & cpu_to_be16(MLX4_CQE_STATUS_TCP | MLX4_CQE_STATUS_UDP)) && (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPOK)) &&