Received: by 10.192.165.156 with SMTP id m28csp748058imm; Mon, 16 Apr 2018 08:07:02 -0700 (PDT) X-Google-Smtp-Source: AIpwx4/Xn2f7dG/W22tV/orOuNZTNKICGWgh82pOkZsltHMhl4NOl+a94LHylNORXZbf/9hucBcS X-Received: by 10.98.227.16 with SMTP id g16mr21640883pfh.171.1523891222530; Mon, 16 Apr 2018 08:07:02 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1523891222; cv=none; d=google.com; s=arc-20160816; b=byqZTGfS8ZZbpxAbzU0ZaUIJO7/jjgaB6+y7F5+dkP3tWQIw1yFYMFUB7lSIm99EVj HyNXfp8liRVUkSpg75ht0fSDBNK2WhyAj4OVtQ0ifefhllD4/I2h8/NipVHaxVAaw5eP +FuC86h65pvOZTe1lKHgpCNzx9+gtck7clZBn+HKD/S999nY/LPSpk+xyVdkp1vjeU3X XEcuexDqyMXzgWsklh0k2nXSf16T69PZzTx1rkKTp+wUcLFTQGG2DawXfBtAmabLcXr2 g58e7KG58/3hl513Gwo3dgllUbLNK8jXwHb7l0xJiyn1872Atm0X1MoVvTHOtS192tor Dh3w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:from:subject:cc:to:message-id:date :arc-authentication-results; bh=5/yHvE5AQjJJd0S/2l7e2rwkxjR51uTodtWKoJrZ9VA=; b=MCHmkpdescJ6fydik/QjoFKGih/yKCMt0PRaTeMva5J0mCWRxgM2rdONoy/2gpkvSE LOmRAvIcwXdau3ely+mLS+MYKMbdS42F3OTXxePdExoli90wjt8IzhWUU7m6LB0Ep6mJ 0tU0+Zs8+3J4cDJ4nA3UP/8mOKMdjci//zvGLiQBghNTG5O9dRHpX7ogq7Dmut1/KBK3 9Z4BqFp4qJn1ltyvuMbXhqekvo6CNtz3fLEZIatLd0dJq7v5U72219/JxMEchYmUkCVN Ys5gwQrCTyAg+Tp6fD2YYR1sYkcy9jR3bcdV/D/h1+tD1ZPtfGsXdILHlpG3A0Agr0wK U5RA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id s36-v6si11895921pld.401.2018.04.16.08.06.24; Mon, 16 Apr 2018 08:07:02 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751857AbeDPPFD (ORCPT + 99 others); Mon, 16 Apr 2018 11:05:03 -0400 Received: from shards.monkeyblade.net ([184.105.139.130]:42318 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750716AbeDPPFC (ORCPT ); Mon, 16 Apr 2018 11:05:02 -0400 Received: from localhost (pool-173-77-163-229.nycmny.fios.verizon.net [173.77.163.229]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 200A514167DD0; Mon, 16 Apr 2018 08:05:02 -0700 (PDT) Date: Mon, 16 Apr 2018 11:05:01 -0400 (EDT) Message-Id: <20180416.110501.92472500114183248.davem@davemloft.net> To: liu.xiang6@zte.com.cn Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, liuxiang_1999@126.com Subject: Re: [PATCH v3] net: davicom: dm9000: Avoid spinlock recursion during dm9000_timeout routine From: David Miller In-Reply-To: <1523695834-6261-1-git-send-email-liu.xiang6@zte.com.cn> References: <1523695834-6261-1-git-send-email-liu.xiang6@zte.com.cn> X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 16 Apr 2018 08:05:02 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Liu Xiang Date: Sat, 14 Apr 2018 16:50:34 +0800 > +static bool dm9000_current_in_timeout(struct board_info *db) > +{ > + bool ret = false; > + > + preempt_disable(); > + ret = (db->timeout_cpu == smp_processor_id()); > + preempt_enable(); This doesn't work. As soon as you do preempt_enable(), smp_processor_id() can change.