From patchwork Wed Jun 22 05:12:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 12890157 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13469C43334 for ; Wed, 22 Jun 2022 05:13:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356900AbiFVFNZ (ORCPT ); Wed, 22 Jun 2022 01:13:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356785AbiFVFNO (ORCPT ); Wed, 22 Jun 2022 01:13:14 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F13535DE0 for ; Tue, 21 Jun 2022 22:13:13 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id a8-20020a25a188000000b0066839c45fe8so13667064ybi.17 for ; Tue, 21 Jun 2022 22:13:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=ieF6vXeFFn+xrybKfdCGWxcLeig/WsIdEGabofxCaJA=; b=Ki9W8TSOm3tpM/R59XTy7+HEmQNJ+yyYp/zy9EDTXbTS59dHkPbTQTSLakAsYj0sbZ gFxkfC7szyIzFmmp4KdzHCWE3aai/cwlBp+Dhj0VgNqsSaxVTR9UX+TUJX6HH2lfsoQl vpBfDsuJNDbxhFaiQcNQy583Dsst/39SDg64QyuhXBoOEvivaYPuNkmUDkQaHmnHmTBH LfdBDmpKT2DySSCo6trMFdkksy0WTi1wIzlrbZiYhctcG7rprdB6mZqPd62Ik2Gguwn5 DdopCiQ4oCohwYFIlCKpBQgZ4YODHyAo1IAJrd6oXfY4Pan1kj5BfXS+DI06Z8LT+DtE ljeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ieF6vXeFFn+xrybKfdCGWxcLeig/WsIdEGabofxCaJA=; b=pShmhz9HuK/CiHcHGfHvnWsZy6t9jpuf+rUWer1/JApRBTsD5HL9YRdGfB5k2r3FCE mnc+rkovdTYrxK3mZwxH22b4JYL+LT+c9+PblHIH7tpzH5iMqHQl1yxm/nR5Y3pOw026 Jl1YeIYo2X9TSvrUZdtdnNODiqnEculmpVKk/FQgo1/sXJltWN+oNYZWgwcBm4RojVlO 2diWEMthbrPKYosSv3pNbljhdZ7j3dWDVptJb9tc0ryFhPQXnaZjdFLA+w5zZDRhqKQE WkiPxaEMmfn7dJYeT5U5dXJ049cahDz4poTkcrCwmJY/Ky7LrRzOOIHHlYxDrp91nbU4 gprA== X-Gm-Message-State: AJIora+MroFkfoB1as96ZrfzFXdhBFTdRgCpOpT+mZ6cUIzsbDv+LazO A7V844YTYp6AOddlBdg/djtm8i8cI+pXOg== X-Google-Smtp-Source: AGRyM1vtZoul9UPlxBorPds7I9CObhq9CYIyevLna7uS+pyPLa1xvRSuSutm7S7B7JgjxQX/ex8d3v3WKAhb/Q== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:395a]) (user=edumazet job=sendgmr) by 2002:a25:30c1:0:b0:64d:f030:b01a with SMTP id w184-20020a2530c1000000b0064df030b01amr1732098ybw.330.1655874792831; Tue, 21 Jun 2022 22:13:12 -0700 (PDT) Date: Wed, 22 Jun 2022 05:12:43 +0000 In-Reply-To: <20220622051255.700309-1-edumazet@google.com> Message-Id: <20220622051255.700309-8-edumazet@google.com> Mime-Version: 1.0 References: <20220622051255.700309-1-edumazet@google.com> X-Mailer: git-send-email 2.37.0.rc0.104.g0611611a94-goog Subject: [PATCH net-next 07/19] ipmr: do not acquire mrt_lock before calling ipmr_cache_unresolved() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org rcu_read_lock() protection is good enough. ipmr_cache_unresolved() uses a dedicated spinlock (mfc_unres_lock) Signed-off-by: Eric Dumazet --- net/ipv4/ipmr.c | 25 ++++++++----------------- 1 file changed, 8 insertions(+), 17 deletions(-) diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index bc8b7504fde6ec3aadd6c0962f23e59c0aac702a..6ea54bc3d9b6555aaa9974d81ba4acd47481724f 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -680,7 +680,7 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify, if (VIF_EXISTS(mrt, tmp)) break; } - mrt->maxvif = tmp+1; + WRITE_ONCE(mrt->maxvif, tmp + 1); } write_unlock_bh(&mrt_lock); @@ -905,7 +905,7 @@ static int vif_add(struct net *net, struct mr_table *mrt, WRITE_ONCE(mrt->mroute_reg_vif_num, vifi); } if (vifi+1 > mrt->maxvif) - mrt->maxvif = vifi+1; + WRITE_ONCE(mrt->maxvif, vifi + 1); write_unlock_bh(&mrt_lock); call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, dev, vifi, mrt->id); @@ -1923,11 +1923,12 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt, kfree_skb(skb); } -static int ipmr_find_vif(struct mr_table *mrt, struct net_device *dev) +/* Called with mrt_lock or rcu_read_lock() */ +static int ipmr_find_vif(const struct mr_table *mrt, struct net_device *dev) { int ct; - - for (ct = mrt->maxvif-1; ct >= 0; ct--) { + /* Pairs with WRITE_ONCE() in vif_delete()/vif_add() */ + for (ct = READ_ONCE(mrt->maxvif) - 1; ct >= 0; ct--) { if (rcu_access_pointer(mrt->vif_table[ct].dev) == dev) break; } @@ -2161,15 +2162,9 @@ int ip_mr_input(struct sk_buff *skb) skb = skb2; } - read_lock(&mrt_lock); vif = ipmr_find_vif(mrt, dev); - if (vif >= 0) { - int err2 = ipmr_cache_unresolved(mrt, vif, skb, dev); - read_unlock(&mrt_lock); - - return err2; - } - read_unlock(&mrt_lock); + if (vif >= 0) + return ipmr_cache_unresolved(mrt, vif, skb, dev); kfree_skb(skb); return -ENODEV; } @@ -2273,18 +2268,15 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb, int vif = -1; dev = skb->dev; - read_lock(&mrt_lock); if (dev) vif = ipmr_find_vif(mrt, dev); if (vif < 0) { - read_unlock(&mrt_lock); rcu_read_unlock(); return -ENODEV; } skb2 = skb_realloc_headroom(skb, sizeof(struct iphdr)); if (!skb2) { - read_unlock(&mrt_lock); rcu_read_unlock(); return -ENOMEM; } @@ -2298,7 +2290,6 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb, iph->daddr = daddr; iph->version = 0; err = ipmr_cache_unresolved(mrt, vif, skb2, dev); - read_unlock(&mrt_lock); rcu_read_unlock(); return err; }