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GET /api/1.1/patches/2223600/?format=api
{ "id": 2223600, "url": "http://patchwork.ozlabs.org/api/1.1/patches/2223600/?format=api", "web_url": "http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260415170844.41355-1-pablo@netfilter.org/", "project": { "id": 26, "url": "http://patchwork.ozlabs.org/api/1.1/projects/26/?format=api", "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 }, "msgid": "<20260415170844.41355-1-pablo@netfilter.org>", "date": "2026-04-15T17:08:44", "name": "[nf,v2,1/3] 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/1.1/people/1315/?format=api", "name": "Pablo Neira Ayuso", "email": "pablo@netfilter.org" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260415170844.41355-1-pablo@netfilter.org/mbox/", "series": [ { "id": 500019, "url": "http://patchwork.ozlabs.org/api/1.1/series/500019/?format=api", "web_url": "http://patchwork.ozlabs.org/project/netfilter-devel/list/?series=500019", "date": "2026-04-15T17:10:38", "name": "[nf,v2,1/3] rculist: add list_splice_rcu() for private lists", "version": 2, "mbox": "http://patchwork.ozlabs.org/series/500019/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2223600/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2223600/checks/", "tags": {}, "headers": { "Return-Path": "\n <netfilter-devel+bounces-11931-incoming=patchwork.ozlabs.org@vger.kernel.org>", "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=ubOpxq+0;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; helo=sea.lore.kernel.org;\n envelope-from=netfilter-devel+bounces-11931-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=\"ubOpxq+0\"", "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 sea.lore.kernel.org (sea.lore.kernel.org\n [IPv6:2600:3c0a:e001:db::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fwp350gpgz1yCv\n\tfor <incoming@patchwork.ozlabs.org>; Thu, 16 Apr 2026 03:26:25 +1000 (AEST)", "from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby sea.lore.kernel.org (Postfix) with ESMTP id 3B76A315F2FC\n\tfor <incoming@patchwork.ozlabs.org>; Wed, 15 Apr 2026 17:08:57 +0000 (UTC)", "from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 1A1D93E5EEA;\n\tWed, 15 Apr 2026 17:08:55 +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 0300133120C;\n\tWed, 15 Apr 2026 17:08:52 +0000 (UTC)", "from localhost.localdomain (mail-agni [217.70.190.124])\n\tby mail.netfilter.org (Postfix) with ESMTPSA id 1EF2B60177;\n\tWed, 15 Apr 2026 19:08:50 +0200 (CEST)" ], "ARC-Seal": "i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1776272934; cv=none;\n b=Bc27cjLx+/KNX3dlsnGlewN78FlSKVD5xisVDA11f7eCCZXE4+Bd0rU8dHak3n7x3zGkk+iGwyj915X17YLhJed/RVjf3ZuIe5dvteDM80ds1vxdkbKi3GPX2zdYPmGsDu84vKaAoUQtXdky+8YYmoY8A8Ios3BaubLadjj0E3w=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1776272934; c=relaxed/simple;\n\tbh=8EdpDbjWpEfY9zXDyutbjs8BUV0E1+6AmdmLmyEMfSA=;\n\th=From:To:Cc:Subject:Date:Message-ID:MIME-Version;\n b=fPzrIajZ75VS92XP+uAuT/JS+NIPuZB7QPdb2P6BzeBGqE8/13vgfhDlm3SUKA+Ve0g9FI/b3Csf5RnTNFJdWini5g4CHdIFwIePW204KVLMZuFV4A5TW22Qt2smQSBPhQXQpFBTHHXUx5q6mjiKyJ218oADo2kfueH0zAtjKF8=", "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=ubOpxq+0; 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=1776272931;\n\tbh=6bOJS2bqcYmFCvqyYFWPjJ+z4vwva44OIAdYCVYUYSo=;\n\th=From:To:Cc:Subject:Date:From;\n\tb=ubOpxq+02y2nkfryzTbNz7OyvqmyTWu6sHYiBPJgeLGpItsTJCx0xYalP8cAMA88b\n\t Kz0ePAVgyk05w6OJM7my66kp4C0bvdquWxhHtmX3yZ5yao7d4Zkya3zQPTWTBwDz6r\n\t Qnov6lW822xlJsuR6zjdMOZksXh1Z8Qs0nQE6wuHFF2KDqzssAZRjB9Alwv75/URnH\n\t jUywN5eqFzvckPQqXNCsu4yBoZwUOpqdt30EmL7fjp9bXP5xl6PyDu9MH/cnltUJUV\n\t XLYlzBDiVnG6kTKY6iCH5Pmns6zxpmKCrxfccyWipanjOJaBy67oY/w7zcx4P2NKg6\n\t JUdhol/zGMnGQ==", "From": "Pablo Neira Ayuso <pablo@netfilter.org>", "To": "netfilter-devel@vger.kernel.org", "Cc": "davem@davemloft.net,\n\tnetdev@vger.kernel.org,\n\tkuba@kernel.org,\n\tpabeni@redhat.com,\n\tedumazet@google.com,\n\tfw@strlen.de,\n\thorms@kernel.org,\n\tjoelagnelf@nvidia.com,\n\tjosh@joshtriplett.org,\n\tboqun@kernel.org,\n\turezki@gmail.com,\n\trostedt@goodmis.org,\n\tmathieu.desnoyers@efficios.com,\n\tjiangshanlai@gmail.com,\n\tqiang.zhang@linux.dev,\n\trcu@vger.kernel.org", "Subject": "[PATCH nf,v2 1/3] rculist: add list_splice_rcu() for private lists", "Date": "Wed, 15 Apr 2026 19:08:44 +0200", "Message-ID": "<20260415170844.41355-1-pablo@netfilter.org>", "X-Mailer": "git-send-email 2.47.3", "Precedence": "bulk", "X-Mailing-List": "netfilter-devel@vger.kernel.org", "List-Id": "<netfilter-devel.vger.kernel.org>", "List-Subscribe": "<mailto:netfilter-devel+subscribe@vger.kernel.org>", "List-Unsubscribe": "<mailto:netfilter-devel+unsubscribe@vger.kernel.org>", "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 that the list to splice is not\nempty. Note that __list_splice_rcu() has no documentation for this\nreason.\n\nSigned-off-by: Pablo Neira Ayuso <pablo@netfilter.org>\n---\nv2: including comments by Paul McKenney.\n\n Except, I have deliberately keep back the suggestion to squash\n __list_splice_rcu() into list_splice_rcu(), I instead removed\n the documentation for __list_splice_rcu(). I am looking\n at other existing list_splice*() function in list.h and rculist.h\n to get this aligned with __list_splice(), which also has no users\n in the tree and no documentation. I find it easier to read with\n __list_splice(), but if this explaination is not sound so...\n\n @Paul: I can post v3 squashing __list_splice_rcu(), just let me\n know.\n\n Thanks!\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", "v2", "1/3" ] }