From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tariq Toukan Subject: Re: [PATCH net-next] net/mlx4_en: CHECKSUM_COMPLETE support for fragments Date: Sun, 1 Apr 2018 11:06:15 +0300 Message-ID: <8c43b222-f736-412b-e87c-017610fc97df@mellanox.com> References: <20180327212114.164202-1-edumazet@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "David S . Miller" , netdev , Eric Dumazet , Willem de Bruijn , Tariq Toukan To: Saeed Mahameed , Eric Dumazet Return-path: Received: from mail-he1eur01on0060.outbound.protection.outlook.com ([104.47.0.60]:33728 "EHLO EUR01-HE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751170AbeDAIG3 (ORCPT ); Sun, 1 Apr 2018 04:06:29 -0400 In-Reply-To: Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 30/03/2018 3:34 AM, Saeed Mahameed wrote: > On Tue, Mar 27, 2018 at 2:21 PM, Eric Dumazet wrote: >> Refine the RX check summing handling to propagate the >> hardware provided checksum so that we do not have to >> compute it later in software. >> >> Signed-off-by: Eric Dumazet >> Cc: Willem de Bruijn >> Cc: Tariq Toukan >> --- >> drivers/net/ethernet/mellanox/mlx4/en_rx.c | 10 ++++------ >> 1 file changed, 4 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c >> index 05787efef492b1c0c6ce540ef73647fad91ce282..5c613c6663da51a4ae792eeb4d8956b54655786b 100644 >> --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c >> +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c >> @@ -821,14 +821,12 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud >> skb_record_rx_queue(skb, cq_ring); >> >> if (likely(dev->features & NETIF_F_RXCSUM)) { >> - if (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_TCP | >> - MLX4_CQE_STATUS_UDP)) { >> + if ((cqe->status & cpu_to_be16(MLX4_CQE_STATUS_TCP | >> + MLX4_CQE_STATUS_UDP)) && >> + (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPOK)) && >> + cqe->checksum == cpu_to_be16(0xffff)) { >> bool l2_tunnel; >> > > LGTM, this code even aligns better with the mlx4 HW documentation: > > "When L4_CSUM field is not supported, L4 checksum for TCP/UDP packets > can be validated by: (IP_OK && (TCP || UDP)) && (checksum == > 0xFFFF))." > Hi, Thanks Eric for your patch. Thanks Saeed for your review while I'm off-work. In IP fragments, MLX4_CQE_STATUS_IPOK is not set in cqe->status. This patch suggests falling back to CHECKSUM_COMPLETE instead of CHECKSUM_NONE. Looks good to me. > in the code we don't even consider L4_CSUM at the moment, As a future > patch, it could be a nice acceleration for the above 3 steps > condition. > Right. Good idea. I'll add it to plans. > Small comment, if we expect that cqe->checksum is NOT likely to be > 0xffff for UDP/TCP packets, maybe it is better performance wise to > move (cqe->checksum == cpu_to_be16(0xffff)) to be evaluated first in > the condition. > It _is_ likely for common TCP/UDP (no IP fragments). Let's keep it this way. >> - if (!((cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPOK)) && >> - cqe->checksum == cpu_to_be16(0xffff))) >> - goto csum_none; >> - >> l2_tunnel = (dev->hw_enc_features & NETIF_F_RXCSUM) && >> (cqe->vlan_my_qpn & cpu_to_be32(MLX4_CQE_L2_TUNNEL)); >> ip_summed = CHECKSUM_UNNECESSARY; >> -- >> 2.17.0.rc1.321.gba9d0f2565-goog >> Acked-by: Tariq Toukan