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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 34B34C7618F for ; Mon, 22 Jul 2019 18:33:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0F11821901 for ; Mon, 22 Jul 2019 18:33:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="nHf9lrxc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729420AbfGVSd3 (ORCPT ); Mon, 22 Jul 2019 14:33:29 -0400 Received: from new3-smtp.messagingengine.com ([66.111.4.229]:45571 "EHLO new3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726770AbfGVSd1 (ORCPT ); Mon, 22 Jul 2019 14:33:27 -0400 Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailnew.nyi.internal (Postfix) with ESMTP id CBBD92237; Mon, 22 Jul 2019 14:33:26 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute3.internal (MEProxy); Mon, 22 Jul 2019 14:33:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:date:from :in-reply-to:message-id:mime-version:references:subject:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm3; bh=BBIr3gIHa0S4VzDEiHvR7PAjPwgOdqLA7KiJfRjHHPQ=; b=nHf9lrxc pdFuqIxMCE07Qho53IyDjn4MNte2wchnddSj96acKehv0NgpnF3DnBCitjLj1U/j 7EjVC3o1Fsu5HGTVLRJPg0+GJLe8r7P9Ck4eQdoR0FkTGlZZb3oRHovgpoeVg6Xb WgnReh0aP635dmyeBQxIMUn7ccT61i+70MpbGK0/STKewzcWZuWsZnFYMjpKH1Bu 5Xq48iNAD9a6MDEIo8LC6HQR6h8dyfbCGIzWEeYZv0jRFCNPpb2Brb78SqAbCBBX v/YOqjCQTTLdQkuKCpkv/TEW0FQSeewzUZE/c0J6/BGLga8uU3Rll8qooJDalOzu p/5AP69vpgmpgA== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduvddrjeeggdduvdelucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefhvffufffkofgjfhgggfestdekre dtredttdenucfhrhhomhepkfguohcuufgthhhimhhmvghluceoihguohhstghhsehiugho shgthhdrohhrgheqnecukfhppeduleefrdegjedrudeihedrvdehudenucfrrghrrghmpe hmrghilhhfrhhomhepihguohhstghhsehiughoshgthhdrohhrghenucevlhhushhtvghr ufhiiigvpedt X-ME-Proxy: Received: from splinter.mtl.com (unknown [193.47.165.251]) by mail.messagingengine.com (Postfix) with ESMTPA id 6256780062; Mon, 22 Jul 2019 14:33:24 -0400 (EDT) From: Ido Schimmel To: netdev@vger.kernel.org Cc: davem@davemloft.net, nhorman@tuxdriver.com, dsahern@gmail.com, roopa@cumulusnetworks.com, nikolay@cumulusnetworks.com, jakub.kicinski@netronome.com, toke@redhat.com, andy@greyhouse.net, f.fainelli@gmail.com, andrew@lunn.ch, vivien.didelot@gmail.com, mlxsw@mellanox.com, Ido Schimmel Subject: [RFC PATCH net-next 03/12] drop_monitor: Document scope of spinlock Date: Mon, 22 Jul 2019 21:31:25 +0300 Message-Id: <20190722183134.14516-4-idosch@idosch.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190722183134.14516-1-idosch@idosch.org> References: <20190722183134.14516-1-idosch@idosch.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Ido Schimmel While 'per_cpu_dm_data' is a per-CPU variable, its 'skb' and 'send_timer' fields can be accessed concurrently by the CPU sending the netlink notification to user space from the workqueue and the CPU tracing kfree_skb(). This spinlock is meant to protect against that. Document its scope and suppress the checkpatch message "spinlock_t definition without comment". Signed-off-by: Ido Schimmel --- net/core/drop_monitor.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index 000ec8b66d1e..35d31b007da4 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -52,7 +52,7 @@ static int trace_state = TRACE_OFF; static DEFINE_MUTEX(net_dm_mutex); struct per_cpu_dm_data { - spinlock_t lock; + spinlock_t lock; /* Protects 'skb' and 'send_timer' */ struct sk_buff *skb; struct work_struct dm_alert_work; struct timer_list send_timer; -- 2.21.0