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=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 702F8C49361 for ; Thu, 17 Jun 2021 21:37:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D751613B4 for ; Thu, 17 Jun 2021 21:37:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231434AbhFQVjh (ORCPT ); Thu, 17 Jun 2021 17:39:37 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:53711 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229816AbhFQVjf (ORCPT ); Thu, 17 Jun 2021 17:39:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623965846; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=V+K4Rzii9x9DcPIEElTMZYJsTVD8g+UmhuIcex1BLcU=; b=iy0RQ42oSxyAWuNLaDe3zANnlZ1ty8ssmtHdf/4yPwKpfDqIeZpgtrri2V8A+GL93FKRN7 yCYhK3a3914EGO1eT/4X3M0ipNyrKnifNd0kBd7r2u2d6wYOP3HzMX/ahxRay7uOROEU/3 VSTCaf+HRTIY1FoxY6ZDrmKao22g714= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-194-IvEl53gRPZS9U5eLGI9WXw-1; Thu, 17 Jun 2021 17:37:25 -0400 X-MC-Unique: IvEl53gRPZS9U5eLGI9WXw-1 Received: by mail-ed1-f70.google.com with SMTP id q7-20020aa7cc070000b029038f59dab1c5so2390511edt.23 for ; Thu, 17 Jun 2021 14:37:25 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=V+K4Rzii9x9DcPIEElTMZYJsTVD8g+UmhuIcex1BLcU=; b=oH7VLFEqh6t7AzQFAn0jQB/lFAUhbeG+qqcMnTwTGDl7nZ+qg4T+3kug9H6qEWYpZO NJQqjjZCAsicZlJbE1DJ/fTtpDRggp/FWkUuHfCA2uMeP9zaK7W3tT3wOBPUoQ6MOaZ7 JzrzQ1niyez3TwSU7hpR0atg4OQ1KiiD/KB/QIFowt8M4Yql1zKMbUwGr4lPAGxla2TB 5REUX7biSFcUnvhkzHvXLHrMcyQzFlJqDLOebydu0NYF1ix3WZxcDjNKInpXg/iBrD9I JJjcTmGDLoc+VNTxbQdZnah6vSyUxmN2kqH9SQtDjGnhPlSeqMVok95uF1ZUxd++xVZ9 pyfw== X-Gm-Message-State: AOAM5303p1yjro78zLU7TNcP6tb0MqNvqh+8paC5dQZcIZaIV6jUnDHi TM1KyI93APs6rBY6n6K6JrdUVZ0fuXSQU3jWQXnB1d8ie9XdNE+s/JjH+VKsTHUnGXTvgsU4mn0 Y9Ed6vcVD+CH5 X-Received: by 2002:a17:907:7b9d:: with SMTP id ne29mr7692190ejc.167.1623965844476; Thu, 17 Jun 2021 14:37:24 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyT3fEGEihEGarB3fpS2Al0EXij4hKluNygNZjVN8leQ1wAJxPYopgkOlxKigP3A1jBe4lPvA== X-Received: by 2002:a17:907:7b9d:: with SMTP id ne29mr7692177ejc.167.1623965844289; Thu, 17 Jun 2021 14:37:24 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk ([45.145.92.2]) by smtp.gmail.com with ESMTPSA id q9sm5018510edw.51.2021.06.17.14.37.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Jun 2021 14:37:22 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 9A79C18072F; Thu, 17 Jun 2021 23:27:54 +0200 (CEST) From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= To: bpf@vger.kernel.org, netdev@vger.kernel.org Cc: Martin KaFai Lau , Hangbin Liu , Jesper Dangaard Brouer , Magnus Karlsson , "Paul E . McKenney" , Jakub Kicinski , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Sunil Goutham , linux-arm-kernel@lists.infradead.org Subject: [PATCH bpf-next v3 06/16] thunderx: remove rcu_read_lock() around XDP program invocation Date: Thu, 17 Jun 2021 23:27:38 +0200 Message-Id: <20210617212748.32456-7-toke@redhat.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210617212748.32456-1-toke@redhat.com> References: <20210617212748.32456-1-toke@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org The thunderx driver has rcu_read_lock()/rcu_read_unlock() pairs around XDP program invocations. However, the actual lifetime of the objects referred by the XDP program invocation is longer, all the way through to the call to xdp_do_flush(), making the scope of the rcu_read_lock() too small. This turns out to be harmless because it all happens in a single NAPI poll cycle (and thus under local_bh_disable()), but it makes the rcu_read_lock() misleading. Rather than extend the scope of the rcu_read_lock(), just get rid of it entirely. With the addition of RCU annotations to the XDP_REDIRECT map types that take bh execution into account, lockdep even understands this to be safe, so there's really no reason to keep it around. Cc: Sunil Goutham Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Toke Høiland-Jørgensen --- drivers/net/ethernet/cavium/thunder/nicvf_main.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c index c33b4e837515..1d752815c69a 100644 --- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c +++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c @@ -555,9 +555,10 @@ static inline bool nicvf_xdp_rx(struct nicvf *nic, struct bpf_prog *prog, xdp_prepare_buff(&xdp, hard_start, data - hard_start, len, false); orig_data = xdp.data; - rcu_read_lock(); + /* This code is invoked within a single NAPI poll cycle and thus under + * local_bh_disable(), which provides the needed RCU protection. + */ action = bpf_prog_run_xdp(prog, &xdp); - rcu_read_unlock(); len = xdp.data_end - xdp.data; /* Check if XDP program has changed headers */ -- 2.32.0 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=-16.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 2DD81C2B9F4 for ; Thu, 17 Jun 2021 21:39:20 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D4F4D61241 for ; Thu, 17 Jun 2021 21:39:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4F4D61241 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=mA3Wd6zh+aacrQDZWF3Ie5LcgV6/2/N3Oq2gRZksYa4=; b=kJmBmPy7or12ST lFLWs/PWQC9Cn/CCvQBvjfig9yV2l82+TfJn+5FU2BbQyo6BOuwSv2kfzajhwZ5D2IHth5raTkFJ2 NPmCVxVMihLzyRI4WQYIqPtqHFYrzsCwMFGxTin/Q9gVaAk+fBVej6d1+MhFqMUol+lr/y8b35+gI FV7NbJ1mXMa64IgKafqIMmYc61Gm3VQMeULR8Qy8WcUO28XkQa/LFNSKz8tIFpzI9MZL0PSHPhxOs OxZzvk8PhqqyhWjXk/6/5uZWqxliqftEPS1MdNg4iXG0DQLOmT/PIYihvxynKLaQthMOtERlXlBtz 9qs/a/sMZ32W5/zHMe5Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ltzhg-00BqxC-5h; Thu, 17 Jun 2021 21:37:36 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ltzhc-00Bqos-JZ for linux-arm-kernel@lists.infradead.org; Thu, 17 Jun 2021 21:37:34 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623965848; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=V+K4Rzii9x9DcPIEElTMZYJsTVD8g+UmhuIcex1BLcU=; b=cU/LhuEYJUtdNuCswaFEzONjeG2u6+bprPR8d/RuE+JLmWlCpqDF26Fkeoz1YMOPC2G90w a3rQdR/HFy6xSFA6gZzGhX7jyVFkOxOSWftqHWqvRCiJD4ouirTb0YSILxx2BmjHpEJ7ZT 8codqpZVrrXvD5XTJq/NjjpT1N9aQWo= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-216-ALptZlvzMUORHuv755K4Ow-1; Thu, 17 Jun 2021 17:37:25 -0400 X-MC-Unique: ALptZlvzMUORHuv755K4Ow-1 Received: by mail-ed1-f70.google.com with SMTP id g13-20020a056402090db02903935a4cb74fso2419583edz.1 for ; Thu, 17 Jun 2021 14:37:25 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=V+K4Rzii9x9DcPIEElTMZYJsTVD8g+UmhuIcex1BLcU=; b=Vc7Jvq/pqcwLb2zlqEt3L2ujdL+R5uEP93WCUvsUd06mCek0+G8NQw1Akl3iGzaAtg WwUO2UtrlS1cd8bobVtXv5OIBlligAWkvAX5X66919soHOS8IttEohB5qANRcSp/irSh tD7GHoEueaBfCWmCNqQdMGUyfN9mdtCoD5J6yEDojaNaB3uq/TcJEn8SSDv/8/Pj9lA2 RDmR0iRGTkQaztdNFDr/7zumpawmxoBK47wJ8/jp7jfssYomYEfPjlTn+N4b9kCH4KJM 2LcrzD34aLxl6r2o7KYh7x67ofBpJlY/ywtnBc0SPmGwvjG58aNhscIyiYaVIDCnNJdE Jtjg== X-Gm-Message-State: AOAM5319Xwp1uWXFCYZKWaID036/BPROlTrbfdErTzKQF1Ve7jCRYAOv yCjcAV6UyYXcrF2kuNK1h6Wc23Am+6ljNBvckednpXiunsQNk3tOm0q5Pj6Ylzmobn6ud1BYB6q QNJmmLPtTrZnGuVhUmqFagQ2aWJi0JFYAcjY= X-Received: by 2002:a17:907:7b9d:: with SMTP id ne29mr7692206ejc.167.1623965844585; Thu, 17 Jun 2021 14:37:24 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyT3fEGEihEGarB3fpS2Al0EXij4hKluNygNZjVN8leQ1wAJxPYopgkOlxKigP3A1jBe4lPvA== X-Received: by 2002:a17:907:7b9d:: with SMTP id ne29mr7692177ejc.167.1623965844289; Thu, 17 Jun 2021 14:37:24 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk ([45.145.92.2]) by smtp.gmail.com with ESMTPSA id q9sm5018510edw.51.2021.06.17.14.37.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Jun 2021 14:37:22 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 9A79C18072F; Thu, 17 Jun 2021 23:27:54 +0200 (CEST) From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= To: bpf@vger.kernel.org, netdev@vger.kernel.org Cc: Martin KaFai Lau , Hangbin Liu , Jesper Dangaard Brouer , Magnus Karlsson , "Paul E . McKenney" , Jakub Kicinski , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Sunil Goutham , linux-arm-kernel@lists.infradead.org Subject: [PATCH bpf-next v3 06/16] thunderx: remove rcu_read_lock() around XDP program invocation Date: Thu, 17 Jun 2021 23:27:38 +0200 Message-Id: <20210617212748.32456-7-toke@redhat.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210617212748.32456-1-toke@redhat.com> References: <20210617212748.32456-1-toke@redhat.com> MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=toke@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210617_143732_763757_15EB0BBF X-CRM114-Status: GOOD ( 15.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org VGhlIHRodW5kZXJ4IGRyaXZlciBoYXMgcmN1X3JlYWRfbG9jaygpL3JjdV9yZWFkX3VubG9jaygp IHBhaXJzIGFyb3VuZCBYRFAKcHJvZ3JhbSBpbnZvY2F0aW9ucy4gSG93ZXZlciwgdGhlIGFjdHVh bCBsaWZldGltZSBvZiB0aGUgb2JqZWN0cyByZWZlcnJlZApieSB0aGUgWERQIHByb2dyYW0gaW52 b2NhdGlvbiBpcyBsb25nZXIsIGFsbCB0aGUgd2F5IHRocm91Z2ggdG8gdGhlIGNhbGwgdG8KeGRw X2RvX2ZsdXNoKCksIG1ha2luZyB0aGUgc2NvcGUgb2YgdGhlIHJjdV9yZWFkX2xvY2soKSB0b28g c21hbGwuIFRoaXMKdHVybnMgb3V0IHRvIGJlIGhhcm1sZXNzIGJlY2F1c2UgaXQgYWxsIGhhcHBl bnMgaW4gYSBzaW5nbGUgTkFQSSBwb2xsCmN5Y2xlIChhbmQgdGh1cyB1bmRlciBsb2NhbF9iaF9k aXNhYmxlKCkpLCBidXQgaXQgbWFrZXMgdGhlIHJjdV9yZWFkX2xvY2soKQptaXNsZWFkaW5nLgoK UmF0aGVyIHRoYW4gZXh0ZW5kIHRoZSBzY29wZSBvZiB0aGUgcmN1X3JlYWRfbG9jaygpLCBqdXN0 IGdldCByaWQgb2YgaXQKZW50aXJlbHkuIFdpdGggdGhlIGFkZGl0aW9uIG9mIFJDVSBhbm5vdGF0 aW9ucyB0byB0aGUgWERQX1JFRElSRUNUIG1hcAp0eXBlcyB0aGF0IHRha2UgYmggZXhlY3V0aW9u IGludG8gYWNjb3VudCwgbG9ja2RlcCBldmVuIHVuZGVyc3RhbmRzIHRoaXMgdG8KYmUgc2FmZSwg c28gdGhlcmUncyByZWFsbHkgbm8gcmVhc29uIHRvIGtlZXAgaXQgYXJvdW5kLgoKQ2M6IFN1bmls IEdvdXRoYW0gPHNnb3V0aGFtQG1hcnZlbGwuY29tPgpDYzogbGludXgtYXJtLWtlcm5lbEBsaXN0 cy5pbmZyYWRlYWQub3JnClNpZ25lZC1vZmYtYnk6IFRva2UgSMO4aWxhbmQtSsO4cmdlbnNlbiA8 dG9rZUByZWRoYXQuY29tPgotLS0KIGRyaXZlcnMvbmV0L2V0aGVybmV0L2Nhdml1bS90aHVuZGVy L25pY3ZmX21haW4uYyB8IDUgKysrLS0KIDEgZmlsZSBjaGFuZ2VkLCAzIGluc2VydGlvbnMoKyks IDIgZGVsZXRpb25zKC0pCgpkaWZmIC0tZ2l0IGEvZHJpdmVycy9uZXQvZXRoZXJuZXQvY2F2aXVt L3RodW5kZXIvbmljdmZfbWFpbi5jIGIvZHJpdmVycy9uZXQvZXRoZXJuZXQvY2F2aXVtL3RodW5k ZXIvbmljdmZfbWFpbi5jCmluZGV4IGMzM2I0ZTgzNzUxNS4uMWQ3NTI4MTVjNjlhIDEwMDY0NAot LS0gYS9kcml2ZXJzL25ldC9ldGhlcm5ldC9jYXZpdW0vdGh1bmRlci9uaWN2Zl9tYWluLmMKKysr IGIvZHJpdmVycy9uZXQvZXRoZXJuZXQvY2F2aXVtL3RodW5kZXIvbmljdmZfbWFpbi5jCkBAIC01 NTUsOSArNTU1LDEwIEBAIHN0YXRpYyBpbmxpbmUgYm9vbCBuaWN2Zl94ZHBfcngoc3RydWN0IG5p Y3ZmICpuaWMsIHN0cnVjdCBicGZfcHJvZyAqcHJvZywKIAl4ZHBfcHJlcGFyZV9idWZmKCZ4ZHAs IGhhcmRfc3RhcnQsIGRhdGEgLSBoYXJkX3N0YXJ0LCBsZW4sIGZhbHNlKTsKIAlvcmlnX2RhdGEg PSB4ZHAuZGF0YTsKIAotCXJjdV9yZWFkX2xvY2soKTsKKwkvKiBUaGlzIGNvZGUgaXMgaW52b2tl ZCB3aXRoaW4gYSBzaW5nbGUgTkFQSSBwb2xsIGN5Y2xlIGFuZCB0aHVzIHVuZGVyCisJICogbG9j YWxfYmhfZGlzYWJsZSgpLCB3aGljaCBwcm92aWRlcyB0aGUgbmVlZGVkIFJDVSBwcm90ZWN0aW9u LgorCSAqLwogCWFjdGlvbiA9IGJwZl9wcm9nX3J1bl94ZHAocHJvZywgJnhkcCk7Ci0JcmN1X3Jl YWRfdW5sb2NrKCk7CiAKIAlsZW4gPSB4ZHAuZGF0YV9lbmQgLSB4ZHAuZGF0YTsKIAkvKiBDaGVj ayBpZiBYRFAgcHJvZ3JhbSBoYXMgY2hhbmdlZCBoZWFkZXJzICovCi0tIAoyLjMyLjAKCgpfX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpsaW51eC1hcm0ta2Vy bmVsIG1haWxpbmcgbGlzdApsaW51eC1hcm0ta2VybmVsQGxpc3RzLmluZnJhZGVhZC5vcmcKaHR0 cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0aW5mby9saW51eC1hcm0ta2VybmVs Cg==