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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F30CBC433EF for ; Wed, 9 Feb 2022 05:52:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232089AbiBIFtn (ORCPT ); Wed, 9 Feb 2022 00:49:43 -0500 Received: from gmail-smtp-in.l.google.com ([23.128.96.19]:46566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235744AbiBIFr5 (ORCPT ); Wed, 9 Feb 2022 00:47:57 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E4242E015279 for ; Tue, 8 Feb 2022 21:47:47 -0800 (PST) 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 8E5F5ED1; Tue, 8 Feb 2022 21:47:28 -0800 (PST) Received: from [10.57.88.245] (unknown [10.57.88.245]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DE3133F718; Tue, 8 Feb 2022 21:47:26 -0800 (PST) Message-ID: <6b91293a-1149-2c77-04a4-421a45d4e1e0@arm.com> Date: Wed, 9 Feb 2022 05:47:24 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [PATCH v2 RESEND 1/4] coresight: etm4x: Add lock for reading virtual context ID comparator To: Leo Yan , Mathieu Poirier , Mike Leach , Alexander Shishkin , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20220204152403.71775-1-leo.yan@linaro.org> <20220204152403.71775-2-leo.yan@linaro.org> From: Suzuki K Poulose In-Reply-To: <20220204152403.71775-2-leo.yan@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Leo On 04/02/2022 15:24, Leo Yan wrote: > Updates to the values and the index are protected via the spinlock. > Ensure we use the same lock to read the value safely. > > Signed-off-by: Leo Yan > Reviewed-by: Suzuki K Poulose > --- > drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c > index 10ef2a29006e..2f3b4eef8261 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c > @@ -2111,7 +2111,9 @@ static ssize_t vmid_val_show(struct device *dev, > struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent); > struct etmv4_config *config = &drvdata->config; > > + spin_lock(&drvdata->spinlock); > val = (unsigned long)config->vmid_val[config->vmid_idx]; > + spin_unlock(&drvdata->spinlock); > return scnprintf(buf, PAGE_SIZE, "%#lx\n", val); > } > I have queued this patch. For the rest, we would need to wait until the helper lands in the rc. Suzuki