From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from SJ2PR03CU001.outbound.protection.outlook.com (mail-westusazon11012030.outbound.protection.outlook.com [52.101.43.30]) (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 2C57D24A076; Thu, 12 Mar 2026 21:31:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.43.30 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773351113; cv=fail; b=cgQWc6dvmSJ5lJuAdWSypbdNNMs6kx8RTjuwBkgkGI5BGlni/zSUocke+4Pr6nBxK3RMQ3fK8Mu580LVQF9cJhyMm/xM10XNmmSA3h3UrjgcGpnZMiH4w6QWOE/Lb35zY/PysbEkxDsNeRmvk9IjB5hYiGHe3tJFKJsRAvv6WMY= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773351113; c=relaxed/simple; bh=tIBCYf81aKRnTXRYop3ezYqDgjUSAFTqPBHwFocvCiU=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=achtAc3UxySuWHEyIjKlGJ+ydYT+cX4b6rSOZo3E+REvpJmgqZDPXYW1chj8ixKZhcevfo/yr2GUfIvcHTD6eiE794BzRF5idpjF6kxpuPOcE+Azu+LTRYCD7vnBnEj5Z8goraMBDt8kvXBQfCkpuJm5WFJHM3p6FHARXB5YObo= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=MI4DccNw; arc=fail smtp.client-ip=52.101.43.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="MI4DccNw" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=ONfyhBLlCTuuGBnZFr+aaPe1fjwJ4wGqTXpX6Dax+yCsDig3NGjIYxzICgd5SFRW4nRBhTXim3YBGoJ03DkSHR60BeTnWfoRxKU4Uy63WTBi6CuAKUWFrn9iyZZDDBiUNkn6mYW9pbENBIiUDhWCHoqxCaM6007g9ZR9ILADdvxUeJke0Qj7+4mTAnYyf9mX+UzWjiCBwPWusXQPvY2FTWsJqxZIfecs3Wxp4igvV3+9fmr5gbinFezes2umJEHcFdYHklYB6VhKvsw0ZT8bs5sIJyGBu5Fn2E49QRUUcSeqR9OS25RBx3wcjh995CFOtoDAf0Y8WiIC6eKcTkzS9Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=E2dBEBc0YATwXLivOwngGwphTh6bIpdIPot4oKdwj3s=; b=QXTEk+iGM16SANpbomssPBpwKNw+v8XjaJP5WvbYa/JXVJsXObHObZph3abxzV0bz5gV7c4hvzJe02PcrfgA20csiuLCA8Op9ZYkK+F8azgkq7O1zKiabr7jolt2XdwRq04W4vB77g7C+rvF2xmqikP2VavJ2n4d9JUdAENlKHKIyfVyhkpUjoe+pVuXjhT5NxGk/EKRu2pp/e5eXa4nljbF89vULp4u6RKF8LX8/Rx9KnPtpzdGY+GXWDq2YR3fquGa0KUySetstwBUbt6CBkKSuhHtYjwgV7vlwP0lqk0vn+w9grr2tNVf+WRa+fWjnxQ54zsGe5IlrfkKYX/M/A== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=E2dBEBc0YATwXLivOwngGwphTh6bIpdIPot4oKdwj3s=; b=MI4DccNwJNlAIJ6vQXowk0NUYvHCdxQQYJQmcN6LjgnyELQjEd9L5HRQ6tcd/hnQnvEHntz5LlIU/+iRVi/vDseXnlBu89ww0TLRNo5vQjMGjiw5SWz+vFmsTdViLrK63EZcoF0ndug0Y7AACfPhaEBE2MMTD+mY9PHBQWvGD74= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from LV8PR12MB9714.namprd12.prod.outlook.com (2603:10b6:408:2a0::5) by CY8PR12MB8410.namprd12.prod.outlook.com (2603:10b6:930:6d::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.4; Thu, 12 Mar 2026 21:31:49 +0000 Received: from LV8PR12MB9714.namprd12.prod.outlook.com ([fe80::8c9f:3a5b:974b:99c6]) by LV8PR12MB9714.namprd12.prod.outlook.com ([fe80::8c9f:3a5b:974b:99c6%6]) with mapi id 15.20.9723.006; Thu, 12 Mar 2026 21:31:49 +0000 Message-ID: Date: Thu, 12 Mar 2026 14:31:44 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 5/9] dax: Track all dax_region allocations under a global resource tree To: Dan Williams , 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: Ard Biesheuvel , Alison Schofield , Vishal Verma , Ira Weiny , Jonathan Cameron , Yazen Ghannam , Dave Jiang , Davidlohr Bueso , Matthew Wilcox , Jan Kara , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Li Ming , Jeff Johnson , Ying Huang , Yao Xingtao , Peter Zijlstra , Greg Kroah-Hartman , Nathan Fontenot , Terry Bowman , Robert Richter , Benjamin Cheatham , Zhijian Li , Borislav Petkov , Tomasz Wolski References: <20260210064501.157591-1-Smita.KoralahalliChannabasappa@amd.com> <20260210064501.157591-6-Smita.KoralahalliChannabasappa@amd.com> <69b2087cb0cb7_2132100c2@dwillia2-mobl4.notmuch> Content-Language: en-US From: "Koralahalli Channabasappa, Smita" In-Reply-To: <69b2087cb0cb7_2132100c2@dwillia2-mobl4.notmuch> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: BY5PR20CA0031.namprd20.prod.outlook.com (2603:10b6:a03:1f4::44) To LV8PR12MB9714.namprd12.prod.outlook.com (2603:10b6:408:2a0::5) Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV8PR12MB9714:EE_|CY8PR12MB8410:EE_ X-MS-Office365-Filtering-Correlation-Id: bbc90ad5-3738-4731-d97b-08de807ec4ed X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|376014|7416014|56012099003|22082099003|18002099003|7053199007; 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Release the resource on >> dax_region teardown. >> >> By enforcing a single global namespace for dax_region allocations, this >> ensures only one of dax_hmem or dax_cxl can successfully register a >> dax_region for a given range. >> >> Co-developed-by: Dan Williams > > Did I send any code for this? If I suggested the locking below, > apologies, otherwise Suggested-by is expected unless code is adopted > from another patch. No sorry the locking was added by me. I will make the changes and drop the locking. > >> Signed-off-by: Dan Williams >> Signed-off-by: Smita Koralahalli >> --- >> drivers/dax/bus.c | 23 ++++++++++++++++++++--- >> 1 file changed, 20 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c >> index fde29e0ad68b..5f387feb95f0 100644 >> --- a/drivers/dax/bus.c >> +++ b/drivers/dax/bus.c >> @@ -10,6 +10,7 @@ >> #include "dax-private.h" >> #include "bus.h" >> >> +static struct resource dax_regions = DEFINE_RES_MEM_NAMED(0, -1, "DAX Regions"); >> static DEFINE_MUTEX(dax_bus_lock); >> >> /* >> @@ -625,6 +626,8 @@ static void dax_region_unregister(void *region) >> { >> struct dax_region *dax_region = region; >> >> + scoped_guard(rwsem_write, &dax_region_rwsem) >> + release_resource(&dax_region->res); > > I continue to dislike what scoped_guard() does to indentation. Often > scoped_guard() usage can just be replaced by "helper that uses guard()" > > However, dax_region_rwsem protects subdivision of a dax_region, not > coordination across regions. > > Also, release_resource() and request_resource() are already protected by > the resource_lock, why is a new lock needed? You are right. I will remove Thanks Smita >