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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 312FECCF9E3 for ; Wed, 12 Nov 2025 15:38:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jmWLeH97fIztN3BxpfVTr0ckNNYcHK6aY96DN2VwNkI=; b=MINUxhKUfBZkQ/zNYJyZp/PT9U C589ba8xNdJXLktwbWG3eliRxzDmitsmBxpL03lJQs+73lMbzeIv8i33fvjA/TIAlSiPF3Z2HTUsu TyDTeIDSNGgU9Ae4CNai5jXUapztsPmqC1ha5+XcCqH0LYtLqXEGnrf+5fUSGMC2rprNcgdjA5CLI ci/aG9FT7Jj+e190cXE3/o/OYZUc24acW29OFwaNHj2knjtb+Jqa4FTngTkk3dRdMdpG0LAI3H/36 LrYcySStmrVNuRgFoF7pbSUkrYf+GAdIphEhhLMSmKmSRY9eiiU09wvzuqdhHCCl4aaNt4fCOD5eu Y0WKpb1A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJCv3-000000094xK-3P2g; Wed, 12 Nov 2025 15:38:01 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJCv0-000000094wO-33EN for linux-arm-kernel@lists.infradead.org; Wed, 12 Nov 2025 15:37:59 +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 17ED01515; Wed, 12 Nov 2025 07:37:50 -0800 (PST) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2670E3F66E; Wed, 12 Nov 2025 07:37:53 -0800 (PST) Message-ID: <83ba6e8f-30be-4e82-ae1f-2443a0f16d3c@arm.com> Date: Wed, 12 Nov 2025 15:37:51 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 10/33] arm_mpam: Add probe/remove for mpam msc driver and kbuild boiler plate To: "Shaopeng Tan (Fujitsu)" , "james.morse@arm.com" Cc: "amitsinght@marvell.com" , "baisheng.gao@unisoc.com" , "baolin.wang@linux.alibaba.com" , "bobo.shaobowang@huawei.com" , "carl@os.amperecomputing.com" , "catalin.marinas@arm.com" , "dakr@kernel.org" , "dave.martin@arm.com" , "david@redhat.com" , "dfustini@baylibre.com" , "fenghuay@nvidia.com" , "gregkh@linuxfoundation.org" , "gshan@redhat.com" , "guohanjun@huawei.com" , "jeremy.linton@arm.com" , "jonathan.cameron@huawei.com" , "kobak@nvidia.com" , "lcherian@marvell.com" , "lenb@kernel.org" , "linux-acpi@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "lpieralisi@kernel.org" , "peternewman@google.com" , "quic_jiles@quicinc.com" , "rafael@kernel.org" , "robh@kernel.org" , "rohit.mathew@arm.com" , "scott@os.amperecomputing.com" , "sdonthineni@nvidia.com" , "sudeep.holla@arm.com" , "will@kernel.org" , "xhao@linux.alibaba.com" References: <20251107123450.664001-1-ben.horgan@arm.com> <20251107123450.664001-11-ben.horgan@arm.com> From: Ben Horgan Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251112_073758_902560_77E1A526 X-CRM114-Status: GOOD ( 12.35 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Shaopeng, On 11/12/25 07:22, Shaopeng Tan (Fujitsu) wrote: > Hello Ben, > >> From: James Morse >> >> Probing MPAM is convoluted. MSCs that are integrated with a CPU may only be >> accessible from those CPUs, and they may not be online. >> Touching the hardware early is pointless as MPAM can't be used until the >> system-wide common values for num_partid and num_pmg have been >> discovered. >> >> Start with driver probe/remove and mapping the MSC. >> >> CC: Carl Worth >> Tested-by: Fenghua Yu >> Tested-by: Shaopeng Tan >> Tested-by: Peter Newman >> Signed-off-by: James Morse >> Signed-off-by: Ben Horgan >> --- [...] >> +static struct mpam_msc *do_mpam_msc_drv_probe(struct platform_device >> +*pdev) { >> + int err; >> + u32 tmp; >> + struct mpam_msc *msc; >> + struct resource *msc_res; >> + struct device *dev = &pdev->dev; >> + >> + lockdep_assert_held(&mpam_list_lock); >> + >> + msc = devm_kzalloc(&pdev->dev, sizeof(*msc), GFP_KERNEL); >> + if (!msc) >> + return ERR_PTR(-ENOMEM); >> + >> + err = devm_mutex_init(dev, &msc->probe_lock); >> + if (err) >> + return ERR_PTR(err); >> + err = devm_mutex_init(dev, &msc->part_sel_lock); >> + if (err) >> + return ERR_PTR(err); >> + msc->id = pdev->id; >> + msc->pdev = pdev; >> + INIT_LIST_HEAD_RCU(&msc->all_msc_list); >> + INIT_LIST_HEAD_RCU(&msc->ris); >> + >> + err = update_msc_accessibility(msc); >> + if (err) >> + return ERR_PTR(err); > > Since the return value of update_msc_accessibility(msc) is always 0, > this check is unnecessary. Yes, I've changed update_msc_accessibility() to return void. > > Best regards, > Shaopeng TAN > Thanks, Ben