{"id":2224332,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2224332/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260417093942.373885-2-pablo@netfilter.org/","project":{"id":26,"url":"http://patchwork.ozlabs.org/api/1.2/projects/26/?format=json","name":"Netfilter Development","link_name":"netfilter-devel","list_id":"netfilter-devel.vger.kernel.org","list_email":"netfilter-devel@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260417093942.373885-2-pablo@netfilter.org>","list_archive_url":null,"date":"2026-04-17T09:39:40","name":"[nf,v6,2/4] rculist: add list_splice_rcu() for private lists","commit_ref":null,"pull_url":null,"state":"changes-requested","archived":false,"hash":"3ab9ef6053b3ca1d8f1c87534bae5b7f60ab9f0a","submitter":{"id":1315,"url":"http://patchwork.ozlabs.org/api/1.2/people/1315/?format=json","name":"Pablo Neira Ayuso","email":"pablo@netfilter.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260417093942.373885-2-pablo@netfilter.org/mbox/","series":[{"id":500296,"url":"http://patchwork.ozlabs.org/api/1.2/series/500296/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/list/?series=500296","date":"2026-04-17T09:39:41","name":"[nf,v6,1/4] netfilter: nf_tables: use list_del_rcu for netlink hooks","version":6,"mbox":"http://patchwork.ozlabs.org/series/500296/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2224332/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2224332/checks/","tags":{},"related":[],"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","netfilter-devel@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=netfilter.org header.i=@netfilter.org\n header.a=rsa-sha256 header.s=2025 header.b=ptQKlgv/;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c15:e001:75::12fc:5321; helo=sin.lore.kernel.org;\n envelope-from=netfilter-devel+bounces-11994-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org\n header.b=\"ptQKlgv/\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=217.70.190.124","smtp.subspace.kernel.org;\n dmarc=none (p=none dis=none) header.from=netfilter.org","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=netfilter.org"],"Received":["from sin.lore.kernel.org (sin.lore.kernel.org\n [IPv6:2600:3c15:e001:75::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fxqzz6ZPPz1yDF\n\tfor ; Fri, 17 Apr 2026 19:57:19 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby sin.lore.kernel.org (Postfix) with ESMTP id 7D080305013B\n\tfor ; Fri, 17 Apr 2026 09:40:31 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id C185F3B6C07;\n\tFri, 17 Apr 2026 09:39:52 +0000 (UTC)","from mail.netfilter.org (mail.netfilter.org [217.70.190.124])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id 1D7A13B47CD;\n\tFri, 17 Apr 2026 09:39:50 +0000 (UTC)","from localhost.localdomain (mail-agni [217.70.190.124])\n\tby mail.netfilter.org (Postfix) with ESMTPSA id 316E860178;\n\tFri, 17 Apr 2026 11:39:49 +0200 (CEST)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1776418792; cv=none;\n b=aqmy4kIzil73CuSSS9XT1dhDnFtROT8L1Lwex+6fnUi4BRdA+a0b0HU1YFoo29JouS0L/aOWtAGIrkDCOOdt08n+GOLHKAxvs/ge54Koj/+2S76B+iTC0yiQH/XywDGtqs1bjiZ9GNF3qUzKPbczfBXnz27Ac+4aXwYfzpt+3V0=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1776418792; c=relaxed/simple;\n\tbh=S3GejDg9W3hcOQC5RNKxkOhw6ILpGzU3/ViOh0Y6tto=;\n\th=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References:\n\t MIME-Version;\n b=qhm0wCHj4BLlRsfZ71v+Ha/7VsZB3LmtpL3GAGoVKsDAzCiLj/HQSZyHYdRzQEtEEPQdnT/v1Gg2pMFZvHysR1yp8D7yyg88zerutWqwD8N2JvcHTbzBjAIu81TXeyDM6/lOUwRkMpkeQRQQlgaiqSVbTvHHqHdbVbUpljIKm90=","ARC-Authentication-Results":"i=1; smtp.subspace.kernel.org;\n dmarc=none (p=none dis=none) header.from=netfilter.org;\n spf=pass smtp.mailfrom=netfilter.org;\n dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org\n header.b=ptQKlgv/; arc=none smtp.client-ip=217.70.190.124","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org;\n\ts=2025; t=1776418789;\n\tbh=3wQwkBO7gN30MIoY+gvXQRgC5GkDuDM//suSpAKMa+w=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=ptQKlgv/qvt4QPh5JLUQQen05w37z5YWFkAls7BdVEyG8tsoWb45lVEh8glqsOoBc\n\t qWBnvLDjBdypIl7don2nmMDenfYFIUbv19s27x9SfyLhAAI8kJo0q1+324FhdzqF+J\n\t eigeNaplABR3UwKI386k2HswsD2SB9Hhet4BXStAJ9p7yYxUvaPxUtAJdg2UUx+L7I\n\t CP+RBK5IKcVCzF6+LtwvbwjfnVF+JYfFfECIrbojcRqW5vDKAu2piW4kE0BwmIGvGn\n\t Xa4y9hQuFS8QNUetJaD7q35HWBrO+GJQvMfWjC1QvbysUsRgDcBZPDXhg+3cSJ5IoD\n\t qMlePxDXoYYWg==","From":"Pablo Neira Ayuso ","To":"netfilter-devel@vger.kernel.org","Cc":"netdev@vger.kernel.org,\n\tfw@strlen.de","Subject":"[PATCH nf,v6 2/4] rculist: add list_splice_rcu() for private lists","Date":"Fri, 17 Apr 2026 11:39:40 +0200","Message-ID":"<20260417093942.373885-2-pablo@netfilter.org>","X-Mailer":"git-send-email 2.47.3","In-Reply-To":"<20260417093942.373885-1-pablo@netfilter.org>","References":"<20260417093942.373885-1-pablo@netfilter.org>","Precedence":"bulk","X-Mailing-List":"netfilter-devel@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit"},"content":"This patch adds a helper function, list_splice_rcu(), to safely splice\na private (non-RCU-protected) list into an RCU-protected list.\n\nThe function ensures that only the pointer visible to RCU readers\n(prev->next) is updated using rcu_assign_pointer(), while the rest of\nthe list manipulations are performed with regular assignments, as the\nsource list is private and not visible to concurrent RCU readers.\n\nThis is useful for moving elements from a private list into a global\nRCU-protected list, ensuring safe publication for RCU readers.\nSubsystems with some sort of batching mechanism from userspace can\nbenefit from this new function.\n\nThe function __list_splice_rcu() has been added for clarity and to\nfollow the same pattern as in the existing list_splice*() interfaces,\nwhere there is a check to ensure that the list to splice is not\nempty. Note that __list_splice_rcu() has no documentation for this\nreason.\n\nReviewed-by: Paul E. McKenney \nSigned-off-by: Pablo Neira Ayuso \n---\nv6: - just a rebase on top of net-next, net is still behind.\n\n include/linux/rculist.h | 29 +++++++++++++++++++++++++++++\n 1 file changed, 29 insertions(+)","diff":"diff --git a/include/linux/rculist.h b/include/linux/rculist.h\nindex 2abba7552605..e3bc44225692 100644\n--- a/include/linux/rculist.h\n+++ b/include/linux/rculist.h\n@@ -261,6 +261,35 @@ static inline void list_replace_rcu(struct list_head *old,\n \told->prev = LIST_POISON2;\n }\n \n+static inline void __list_splice_rcu(struct list_head *list,\n+\t\t\t\t struct list_head *prev,\n+\t\t\t\t struct list_head *next)\n+{\n+\tstruct list_head *first = list->next;\n+\tstruct list_head *last = list->prev;\n+\n+\tlast->next = next;\n+\tfirst->prev = prev;\n+\tnext->prev = last;\n+\trcu_assign_pointer(list_next_rcu(prev), first);\n+}\n+\n+/**\n+ * list_splice_rcu - splice a non-RCU list into an RCU-protected list,\n+ * designed for stacks.\n+ * @list:\tthe non RCU-protected list to splice\n+ * @head:\tthe place in the existing RCU-protected list to splice\n+ *\n+ * The list pointed to by @head can be RCU-read traversed concurrently with\n+ * this function.\n+ */\n+static inline void list_splice_rcu(struct list_head *list,\n+\t\t\t\t struct list_head *head)\n+{\n+\tif (!list_empty(list))\n+\t\t__list_splice_rcu(list, head, head->next);\n+}\n+\n /**\n * __list_splice_init_rcu - join an RCU-protected list into an existing list.\n * @list:\tthe RCU-protected list to splice\n","prefixes":["nf","v6","2/4"]}