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=-4.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 D91C0C433E1 for ; Wed, 24 Jun 2020 21:28:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ABE55207FC for ; Wed, 24 Jun 2020 21:28:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="TpJYuTv/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403823AbgFXV2G (ORCPT ); Wed, 24 Jun 2020 17:28:06 -0400 Received: from mail.zx2c4.com ([192.95.5.64]:46477 "EHLO mail.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390437AbgFXV2F (ORCPT ); Wed, 24 Jun 2020 17:28:05 -0400 Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 5b8dc3a7; Wed, 24 Jun 2020 21:09:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=date:from:to :cc:subject:message-id:references:mime-version:content-type :in-reply-to; s=mail; bh=lBGWaWSniCgW2rkSG/g/Me2LyUA=; b=TpJYuTv /1y34hOuTp3rYLWpfMyZ6W/HtiRi8W4pwjFKS7i+PFCWV08NEbGtrNA57aZ6Z7c3 0qAax0qjvlsFC7xPn7QTTLLte5Av//wNT9hTkQ4yFYp8B42OaVErvSvDLFnn3jIn e4yxTFLsvjkhgt+TmZNfrMOPlw7uxZ8tQ7IqBYxGFu0WLo586W46V4ySdp3mNwS7 A+1PhLEALi2HHsrb+N00xAyQ27NdJPOvC3DvvdtsfRpLgty6Ov7DXpX8JueSA1p/ g9cnwlDhD41RDe3NzWpslaGQ7IVOpiqsnOapEEZsGYuDkk/t0eBnh1jcYHCWMd9x SSpd6S67oxtCALA== Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 6cb6511a (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Wed, 24 Jun 2020 21:09:00 +0000 (UTC) Date: Wed, 24 Jun 2020 15:28:02 -0600 From: "Jason A. Donenfeld" To: Alexander Lobakin Cc: "David S. Miller" , Edward Cree , Jiri Pirko , Eric Dumazet , Ido Schimmel , Paolo Abeni , Petr Machata , Sabrina Dubroca , Florian Fainelli , Jassi Brar , Ilias Apalodimas , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 net-next] net: core: use listified Rx for GRO_NORMAL in napi_gro_receive() Message-ID: <20200624212802.GA1386764@zx2c4.com> References: <20191014080033.12407-1-alobakin@dlink.ru> <20200624210606.GA1362687@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200624210606.GA1362687@zx2c4.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Jun 24, 2020 at 03:06:10PM -0600, Jason A. Donenfeld wrote: > Hi Alexander, > > This patch introduced a behavior change around GRO_DROP: > > napi_skb_finish used to sometimes return GRO_DROP: > > > -static gro_result_t napi_skb_finish(gro_result_t ret, struct sk_buff *skb) > > +static gro_result_t napi_skb_finish(struct napi_struct *napi, > > + struct sk_buff *skb, > > + gro_result_t ret) > > { > > switch (ret) { > > case GRO_NORMAL: > > - if (netif_receive_skb_internal(skb)) > > - ret = GRO_DROP; > > + gro_normal_one(napi, skb); > > > > But under your change, gro_normal_one and the various calls that makes > never propagates its return value, and so GRO_DROP is never returned to > the caller, even if something drops it. > > Was this intentional? Or should I start looking into how to restore it? > > Thanks, > Jason For some context, I'm consequently mulling over this change in my code, since checking for GRO_DROP now constitutes dead code: diff --git a/drivers/net/wireguard/receive.c b/drivers/net/wireguard/receive.c index 91438144e4f7..9b2ab6fc91cd 100644 --- a/drivers/net/wireguard/receive.c +++ b/drivers/net/wireguard/receive.c @@ -414,14 +414,8 @@ static void wg_packet_consume_data_done(struct wg_peer *peer, if (unlikely(routed_peer != peer)) goto dishonest_packet_peer; - if (unlikely(napi_gro_receive(&peer->napi, skb) == GRO_DROP)) { - ++dev->stats.rx_dropped; - net_dbg_ratelimited("%s: Failed to give packet to userspace from peer %llu (%pISpfsc)\n", - dev->name, peer->internal_id, - &peer->endpoint.addr); - } else { - update_rx_stats(peer, message_data_len(len_before_trim)); - } + napi_gro_receive(&peer->napi, skb); + update_rx_stats(peer, message_data_len(len_before_trim)); return; dishonest_packet_peer: