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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DECB3C43217 for ; Mon, 1 Nov 2021 09:50:19 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A134B600D4 for ; Mon, 1 Nov 2021 09:50:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A134B600D4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Cc:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=edf9hnrR2GiNtLgtH5TRTpNRqbpjVQLFMAvoThgglzs=; b=E+44XxnVQ6aWsZBf5DQ7Ob923J ARyI5CfG0v4TM8trK4YNm61MGyvzG2HNElBa9M64Qk5PG9pCxndoRAAEGrHvlgXRX+QOOYvk5YHuJ omvmhs2JI/ZayIHegENd0FVATsxfHy0KgVPLKCSZmbS8EuRLLsuwrR5qfePvNJZ8SbhaY1lLR8zpG Z9JXcEoUyVloa2/NT9+ifg7/+Lg3odwmKVGWuJCNH5j5GDcFOEbbn1uOJAmLbyHCNiVSLVnjZLRO4 tNqgS28m4jikxforVGEIUnjuG5DaIXL00EoiOdjPjIqFbf8cQIsgBQynxQvQB6SeLD6QYgdNj9VEY OoSTXOdQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mhTwI-00FrwX-NS; Mon, 01 Nov 2021 09:49:14 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mhTwF-00FrvN-7Q for linux-arm-kernel@lists.infradead.org; Mon, 01 Nov 2021 09:49:12 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D8EB3106F; Mon, 1 Nov 2021 02:49:09 -0700 (PDT) Received: from [10.57.47.15] (unknown [10.57.47.15]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 90E083F719; Mon, 1 Nov 2021 02:49:08 -0700 (PDT) Subject: Re: [PATCH v1 1/4] coresight: etm4x: Add lock for reading virtual context ID comparator To: Leo Yan , Mathieu Poirier , Mike Leach , Alexander Shishkin , James Clark , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20211031144214.237879-1-leo.yan@linaro.org> <20211031144214.237879-2-leo.yan@linaro.org> From: Suzuki K Poulose Message-ID: Date: Mon, 1 Nov 2021 09:49:06 +0000 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <20211031144214.237879-2-leo.yan@linaro.org> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211101_024911_369286_D061A946 X-CRM114-Status: GOOD ( 11.10 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Leo On 31/10/2021 14:42, Leo Yan wrote: > When read the virtual context ID comparator value via sysfs node, the > driver firstly reads out the index, then reads the comparator value > based on index. > > This patch adds the spinlock to protect the atomicity for up two steps. minor nit: This could be : "Updates to the values and the index are protected via the spinlock. Ensure we use the same lock to read the value safely" With that: Reviewed-by: Suzuki K Poulose _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel