From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F16A930E0DB; Thu, 4 Sep 2025 17:35:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757007360; cv=none; b=e6PLVVW6iK6LWdPRAMQ6tlV/vViSodS5zsL+FjO80uUa1vcIJrcoyUEdZ0fSMCNCI4+970gBLL5V2l6QuxueeSEI8b7s1NKSbLKW0STdtX+9BCvulFMNcxtopHIiyi4RjWiWZnZ0cBI3tUO/1aWBbSJbHK5rD/YBRv+TxGlI8fY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757007360; c=relaxed/simple; bh=CRYMSgrsarXvYi1//yRrN7dpQZoWaaGRrmsLjMroS9s=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=rDQ2PaixBTROqM8IMD9YU7HtJ9wpauTx7Xn5MCzwLGqCE64nhUU6ou4NRkaj+42DLqZGDLbwCOzQWkN/5udqoXP345JYtxCMchImS1w71n5SKtclHQFTJob5zy7CWUgDRdVqw2zyuJGQASvoq1Mq06k3EsHSgt89Mwhlh563XBI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=fail smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=XI4K3Fcb; arc=none smtp.client-ip=192.198.163.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="XI4K3Fcb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1757007359; x=1788543359; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=CRYMSgrsarXvYi1//yRrN7dpQZoWaaGRrmsLjMroS9s=; b=XI4K3Fcb5F9w9/rZd+sovXpUBBejuCqBqJIoco2iGw4CNwYWklddMJ0P BupBVJnb6xK02nUukJ36x1w2wr/J+H6IlmVopbEzVVkGTpZ0Lv8p869vc E6ZdtuBwYXGGujYCy1CYK6ariAv+KB3MCCs3KuI7XdJv9gx74Y380CVDl 0S6V76uBKzBsoGv2F21Ck3GBhdv9e3l+ElB2xL6KvASHbhPX+aGhrv7fQ CzKSSEam9RnHYNb7yTS1jQRzTVVdkKEbx2Idke1UjYf6K9DZ7oXf3/qbe s2Sj+IAW40b2yG5sVFI8DHQUuWvlact75xVvy3ZBJ8cJ2ckWjYA+/wBhh g==; X-CSE-ConnectionGUID: 2mCh0UJwTrWFECSrLJoZFA== X-CSE-MsgGUID: cnIIHEYVRGGVW5WPPSe+zg== X-IronPort-AV: E=McAfee;i="6800,10657,11543"; a="58569649" X-IronPort-AV: E=Sophos;i="6.18,239,1751266800"; d="scan'208";a="58569649" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Sep 2025 10:35:58 -0700 X-CSE-ConnectionGUID: M1fSyPrMSqKYRsjrqVUZaQ== X-CSE-MsgGUID: 5tFWot6LQXCV9U/ClRxpgg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,239,1751266800"; d="scan'208";a="176289057" Received: from cmdeoliv-mobl4.amr.corp.intel.com (HELO [10.125.110.24]) ([10.125.110.24]) by orviesa004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Sep 2025 10:35:56 -0700 Message-ID: <7c8ff1d6-1c74-4f46-a96d-74336451d81a@intel.com> Date: Thu, 4 Sep 2025 10:35:55 -0700 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/6] dax/hmem: Request cxl_acpi and cxl_pci before walking Soft Reserved ranges To: Smita Koralahalli , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-pm@vger.kernel.org Cc: Davidlohr Bueso , Jonathan Cameron , Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams , Matthew Wilcox , Jan Kara , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Li Ming , Jeff Johnson , Ying Huang , Yao Xingtao , Peter Zijlstra , Greg KH , Nathan Fontenot , Terry Bowman , Robert Richter , Benjamin Cheatham , PradeepVineshReddy Kodamati , Zhijian Li References: <20250822034202.26896-1-Smita.KoralahalliChannabasappa@amd.com> <20250822034202.26896-3-Smita.KoralahalliChannabasappa@amd.com> Content-Language: en-US From: Dave Jiang In-Reply-To: <20250822034202.26896-3-Smita.KoralahalliChannabasappa@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/21/25 8:41 PM, Smita Koralahalli wrote: > Ensure that cxl_acpi has published CXL Window resources before dax_hmem > walks Soft Reserved ranges. > > Replace MODULE_SOFTDEP("pre: cxl_acpi") with an explicit, synchronous > request_module("cxl_acpi"). MODULE_SOFTDEP() only guarantees eventual > loading, it does not enforce that the dependency has finished init > before the current module runs. This can cause dax_hmem to start before > cxl_acpi has populated the resource tree, breaking detection of overlaps > between Soft Reserved and CXL Windows. > > Also, request cxl_pci before dax_hmem walks Soft Reserved ranges. Unlike > cxl_acpi, cxl_pci attach is asynchronous and creates dependent devices > that trigger further module loads. Asynchronous probe flushing > (wait_for_device_probe()) is added later in the series in a deferred > context before dax_hmem makes ownership decisions for Soft Reserved > ranges. > > Signed-off-by: Smita Koralahalli > Signed-off-by: Dan Williams Reviewed-by: Dave Jiang > --- > drivers/dax/hmem/hmem.c | 17 ++++++++++------- > 1 file changed, 10 insertions(+), 7 deletions(-) > > diff --git a/drivers/dax/hmem/hmem.c b/drivers/dax/hmem/hmem.c > index d5b8f06d531e..9277e5ea0019 100644 > --- a/drivers/dax/hmem/hmem.c > +++ b/drivers/dax/hmem/hmem.c > @@ -146,6 +146,16 @@ static __init int dax_hmem_init(void) > { > int rc; > > + /* > + * Ensure that cxl_acpi and cxl_pci have a chance to kick off > + * CXL topology discovery at least once before scanning the > + * iomem resource tree for IORES_DESC_CXL resources. > + */ > + if (IS_ENABLED(CONFIG_DEV_DAX_CXL)) { > + request_module("cxl_acpi"); > + request_module("cxl_pci"); > + } > + > rc = platform_driver_register(&dax_hmem_platform_driver); > if (rc) > return rc; > @@ -166,13 +176,6 @@ static __exit void dax_hmem_exit(void) > module_init(dax_hmem_init); > module_exit(dax_hmem_exit); > > -/* Allow for CXL to define its own dax regions */ > -#if IS_ENABLED(CONFIG_CXL_REGION) > -#if IS_MODULE(CONFIG_CXL_ACPI) > -MODULE_SOFTDEP("pre: cxl_acpi"); > -#endif > -#endif > - > MODULE_ALIAS("platform:hmem*"); > MODULE_ALIAS("platform:hmem_platform*"); > MODULE_DESCRIPTION("HMEM DAX: direct access to 'specific purpose' memory");