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=-12.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 7F9C0C4743C for ; Wed, 23 Jun 2021 08:30:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 664F161164 for ; Wed, 23 Jun 2021 08:30:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230185AbhFWIcy (ORCPT ); Wed, 23 Jun 2021 04:32:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229833AbhFWIcx (ORCPT ); Wed, 23 Jun 2021 04:32:53 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47D06C061756 for ; Wed, 23 Jun 2021 01:30:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Mime-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=2o8U6wO1ezj+PTLTl7WYcru7Od8Mt0Ngo/zHz3W4TIM=; b=gdViTWEmUW0Qo02zAQ6/qpCUDI dJSasi64kX7XDYNeSEpdwQWwmQ3nYalf4ADk8RuP7QxQxE221InlJCPIpFgYtygTHrZP7o1cLMuyl R+jyWZXeF9iWAY4vN+ZZGNhcjmGR7I+GxDL0ts/oHDjaqtNI2zhR519SiRhvT3C1crPrujvzY11RV lG5fPuhboO1j6OC5ZGkD5so6c1JNz9R/PLbqDGXKYc/vSgGKP1da5rIYbAPCkZzvjWpHBCZfpZbpb GiIJE1LEHiyzx61IJ7SYUBvKOAVDS9eYid+lvy1uM9MckAy/8aBU1jhgV6wMGLZtzzmDu1okPKY1O Cpz+29OA==; Received: from [2001:8b0:10b:1::3ae] (helo=u3832b3a9db3152.infradead.org) by bombadil.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1lvyHL-009vzb-0D; Wed, 23 Jun 2021 08:30:35 +0000 Message-ID: <7dbdbee99c21951d45e37c67ccaed4ff482428ff.camel@infradead.org> Subject: Re: [PATCH v2 1/4] net: tun: fix tun_xdp_one() for IFF_TUN mode From: David Woodhouse To: Jason Wang , netdev@vger.kernel.org Cc: Eugenio =?ISO-8859-1?Q?P=E9rez?= Date: Wed, 23 Jun 2021 09:30:32 +0100 In-Reply-To: References: <03ee62602dd7b7101f78e0802249a6e2e4c10b7f.camel@infradead.org> <20210622161533.1214662-1-dwmw2@infradead.org> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/x-pkcs7-signature"; boundary="=-ucaRKLZE8t1OPucO7hdo" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 Mime-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org --=-ucaRKLZE8t1OPucO7hdo Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2021-06-23 at 11:45 +0800, Jason Wang wrote: > As replied in previous version, it would be better if we can unify=20 > similar logic in tun_get_user(). Ah sorry, I missed that the first time. Yes, that was my initial inclination too. But in the tun_get_user() case we already *have* "pi", having read it separately into a local variable; it never made it to the skb. So the cases are subtly different enough that abstracting it out didn't seem to make sense. If I try harder to unify it, I suppose it looks something like this and *might* just make the cut for "simple enough to be backported to stable kernels in a bug fix". I'll add the PI mode to my test cases and try it (as well as *actually* unifying the offending code, of course). --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -2332,10 +2332,12 @@ static int tun_xdp_one(struct tun_struct *tun, unsigned int datasize =3D xdp->data_end - xdp->data; struct tun_xdp_hdr *hdr =3D xdp->data_hard_start; struct virtio_net_hdr *gso =3D NULL; + struct tun_pi *pi =3D NULL; struct bpf_prog *xdp_prog; struct sk_buff *skb =3D NULL; u32 rxhash =3D 0, act; int buflen =3D hdr->buflen; + int reservelen =3D xdp->data - xdp->data_hard_start; int err =3D 0; bool skb_xdp =3D false; struct page *page; @@ -2343,6 +2345,11 @@ static int tun_xdp_one(struct tun_struct *tun, if (tun->flags & IFF_VNET_HDR) gso =3D &hdr->gso; =20 + if (!(tun->flags & IFF_NO_PI)) { + pi =3D xdp->data; + reservelen +=3D sizeof(*pi); + } + xdp_prog =3D rcu_dereference(tun->xdp_prog); if (xdp_prog) { if (gso && gso->gso_type) { @@ -2388,7 +2395,7 @@ static int tun_xdp_one(struct tun_struct *tun, goto out; } =20 - skb_reserve(skb, xdp->data - xdp->data_hard_start); + skb_reserve(skb, reservelen); skb_put(skb, xdp->data_end - xdp->data); =20 if (gso && virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun= ))) { --=-ucaRKLZE8t1OPucO7hdo Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCECow ggUcMIIEBKADAgECAhEA4rtJSHkq7AnpxKUY8ZlYZjANBgkqhkiG9w0BAQsFADCBlzELMAkGA1UE BhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgG A1UEChMRQ09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhl bnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0EwHhcNMTkwMTAyMDAwMDAwWhcNMjIwMTAxMjM1 OTU5WjAkMSIwIAYJKoZIhvcNAQkBFhNkd213MkBpbmZyYWRlYWQub3JnMIIBIjANBgkqhkiG9w0B AQEFAAOCAQ8AMIIBCgKCAQEAsv3wObLTCbUA7GJqKj9vHGf+Fa+tpkO+ZRVve9EpNsMsfXhvFpb8 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