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=-4.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED 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 5732EC43381 for ; Tue, 26 Mar 2019 15:02:53 +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 21CF82075C for ; Tue, 26 Mar 2019 15:02:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="DhWQ3OxH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 21CF82075C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc: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:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=sslFv7DU8Kr7vTUclPKKikAqYXynKX/GVu1EP+lsbjs=; b=DhWQ3OxHnWqMu4ZQDCGaHsSfG nVg0W9DlzBDpcn6/zTZ87pfqNJlWkCCNc1vgvYYyVP7oAZL2P9pYrLyk145zUDpr/Qj2nv35OWR/D 3rC4sXndlLIyKKY3PKIQQFwlBImzTfmHHOzhwYkPMy2L9e1VWqbu8+LXi7J3Dy9WGUWVI0bc+a7XR RPDvaxvEGFFUWk0DvdCdxHImrfOhLoW+aLU4GDuE3nBBrwj5I3svKOM7t/vSOXj+uCDlah4sT6jS4 gPNSDUTM5w6A53FIwMys44Z2CeqACG/PANjIhjuNrvAqguOgi9BBG8dpfEgWZRMNCGwN5V/GiyBf1 yG+2MyrgQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h8nb7-0000iV-Sg; Tue, 26 Mar 2019 15:02:41 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h8nb3-0000i2-Gl for linux-arm-kernel@lists.infradead.org; Tue, 26 Mar 2019 15:02:39 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E8C0080D; Tue, 26 Mar 2019 08:02:36 -0700 (PDT) Received: from [10.37.12.89] (unknown [10.37.12.89]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5A65D3F575; Tue, 26 Mar 2019 08:02:35 -0700 (PDT) Subject: Re: [PATCH v2 05/16] coresight: Move reference counting inside sink drivers To: mathieu.poirier@linaro.org, linux-arm-kernel@lists.infradead.org References: <20190325215632.17013-1-mathieu.poirier@linaro.org> <20190325215632.17013-6-mathieu.poirier@linaro.org> From: Suzuki K Poulose Message-ID: Date: Tue, 26 Mar 2019 15:04:49 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20190325215632.17013-6-mathieu.poirier@linaro.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190326_080237_563425_9D09F7D2 X-CRM114-Status: GOOD ( 11.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alexander.shishkin@linux.intel.com, peterz@infradead.org, coresight@lists.linaro.org, Mike.Leach@arm.com, leo.yan@linaro.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 03/25/2019 09:56 PM, Mathieu Poirier wrote: > When operating in CPU-wide mode with an N:1 source/sink HW topology, > multiple CPUs can access a sink concurrently. As such reference counting > needs to happen when the device's spinlock is held to avoid racing with > other operations (start(), update(), stop()), such as: > > session A Session B > ----- ------- > > enable_sink > atomic_inc(refcount) = 1 > > ... > > atomic_dec(refcount) = 0 enable_sink > if (refcount == 0) disable_sink > atomic_inc() > > Signed-off-by: Mathieu Poirier > --- 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