From nobody Mon Apr 6 16:12:46 2026 Received: from CY7PR03CU001.outbound.protection.outlook.com (mail-westcentralusazon11010029.outbound.protection.outlook.com [40.93.198.29]) (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 C7F1836920E for ; Thu, 19 Mar 2026 03:36:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.198.29 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773891419; cv=fail; b=ZSfrQ4tEmn+HRtdpWOCZKpQVJnEeULasZsBAKzd6vXnEMo5p9Jmw+SIuxmtjFK2XMN/XuLz5rIMb27J/vp8ajtFN522XKMGfKW/ILKFasdBm8dVjN6Gwv1ohQ6uaJYm8PvgggHEXuPVxkzYDw42b4p6HsCVycL9lr2pSWftH2Qo= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773891419; c=relaxed/simple; bh=gvWPn+XXlxwnJpLbe0ibQWkUCmxpFbcMgeZqkrJyAsM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=MsXWM4gNk9xHhLF8+4PyM/5+5XrPOhsSaRdy7synkPaJnnZ2XgCUv1o9tDO7Lzzy3iFnSN4aVtYCLHox4yzo8sTlB83BXiBe3LDhIk53T3rDtAWli5TDGOmd9fRl9P0/Ngn/G5WBaxEiQdspXP65fS3NvZaNwsKoaLF3by7maBg= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=IEAkzkWu; arc=fail smtp.client-ip=40.93.198.29 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="IEAkzkWu" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=VPMyMQnUM9op5M17EhGfN2NHlFBsxfcS9xC1UGZO37jOgnOE6THktzgwdAgdlPIcEe/ISlu3fuWZ65WXH8a2QW+9HkHWwcgono18PAwzEnLwEQ3S4BZYGs0ZsHqwUMnb2FkWSx4QwqC/+8YizhhjS6i9Y3wa42LqeFKW0IpUM36Igx6RV2lKXtMviwnUPoGrKtlvPuJRDdx3IoZDZpB7jVmvPWLC6D7j8waj82x7mbvs5jN9YT6j7FBvvLWtOlFipYeGiL/+I9FcBA5N3SCLpmot6afLIHuNuwCBn9v3yQPUBSTbBqme68DAVw1DZ3OWuG/TzDMayHSwiqw/ZWrXqg== 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=fIRtjprekt3sjms8lcbaPz8KzLbwVpjx5svOpUIs6gM=; b=sFf1hpMzpSRVOLILLzjWCit8nV/w2oIQdaW0KPKFPWG+xdott3uHdCLEqUyPbVzh5vf6yAoxXIPY62EMeysDlv1dVPJeXfpDr8U/i98gE141IVsq5laDrSXemxuS/C44EXsqzUpNsSOe+1/A6vMmaTGMUOcRgO0Y8wDdkG5OyZYP8m39xiuP1a1De4PCCxajMYXupP3szXifUnKcK6Fexz6Jp1HhpfY02UfqpbIwOpQbIRzdMcgqe+qzo3vIzcMh0Mmc5ZrVavoJ0mzjA/AUM/+n8zj6kwenoslaLBhmGhQ0gAY9QL/acMVEoqOG40U9KVUYe6Ee/9YwPbA0ftGXgQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=fIRtjprekt3sjms8lcbaPz8KzLbwVpjx5svOpUIs6gM=; b=IEAkzkWumN7ADwpsJKIbXEAkSyzxFYs0aLdhKpTJk+BU3/VCrieQlAskDcfwksoZoZuC0JK5kJkoVixcf/2YQBqbfuVH3Y1V8kL1oa50b599JwKlsk8ApbE3pjzkBZLGkxwT1wggM/iX9gDeGOsYqO1jdilnBgvarJa6K9ReZBdJYPA2pUiILqJ5IHVtJObDjSSSnAouf99+df2FBWiX/OmoVroLY8ncxJ6GdD1kVmZqQx7pgO8s/Zm+RJEBrWxv26LfYg84VWnDKO6UqXvQWSIimMamBs4E2KWOAdK15EgF1OTB9YPSmXQ306zPP5J31fti8KvwiueDlUS6bPcY5w== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from PH0PR12MB8800.namprd12.prod.outlook.com (2603:10b6:510:26f::12) by DS0PR12MB8199.namprd12.prod.outlook.com (2603:10b6:8:de::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9745.9; Thu, 19 Mar 2026 03:36:53 +0000 Received: from PH0PR12MB8800.namprd12.prod.outlook.com ([fe80::f79d:ddc5:2ad7:762d]) by PH0PR12MB8800.namprd12.prod.outlook.com ([fe80::f79d:ddc5:2ad7:762d%4]) with mapi id 15.20.9745.007; Thu, 19 Mar 2026 03:36:53 +0000 From: Yury Norov To: Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Thomas Gleixner , Nam Cao , "Jiri Slaby (SUSE)" , Yury Norov , Kees Cook , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Cc: Linus Torvalds Subject: [PATCH 1/2] Revert "powerpc/xive: Fix the size of the cpumask used in xive_find_target_in_mask()" Date: Wed, 18 Mar 2026 23:36:45 -0400 Message-ID: <20260319033647.881246-2-ynorov@nvidia.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260319033647.881246-1-ynorov@nvidia.com> References: <20260319033647.881246-1-ynorov@nvidia.com> Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: BN9PR03CA0962.namprd03.prod.outlook.com (2603:10b6:408:109::7) To PH0PR12MB8800.namprd12.prod.outlook.com (2603:10b6:510:26f::12) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH0PR12MB8800:EE_|DS0PR12MB8199:EE_ X-MS-Office365-Filtering-Correlation-Id: 01c8c2c6-398c-49aa-076f-08de8568c344 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|10070799003|366016|22082099003|18002099003|56012099003|921020; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH0PR12MB8800.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(376014)(10070799003)(366016)(22082099003)(18002099003)(56012099003)(921020);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?7Bcqe+ddoAZomTX1jG5J8BzuSHXYGpYyWLRunB2Ml6HRJMupuXPnXCIWuNoS?= =?us-ascii?Q?iAOGrvzLeP7OVmvrFr6/Oy19KPrguk8gDcJSQ3qMFpiu8FBAiBgJizREa6hn?= =?us-ascii?Q?v2USjP3ACkW3CKxgwcm0AS5FjQ08JhVY5oflsdBTzTa6YBowsTJSUBRKq4Yr?= =?us-ascii?Q?sMo8gsM3EaMXiRlMtRBd2i+svz4BAjXXzOlO/EoRpyum6F93nWQ9zAkD5VlK?= =?us-ascii?Q?CnX0yKLVsH4YUNaqcecjCX9MfZvAMO3ySbzV/0b8mtSJ7Ga5dRB7puwiykdF?= =?us-ascii?Q?DPUUTOjuxBi/ZHKhQ422Pxipv0Et1tRoNEelaQDhFA1aU8eHf1uTnAJuW7ic?= =?us-ascii?Q?Cc1QYTIgodphrvbxhCv2QAwb+/iz8cWk/cwCvjqcQA6C0sPfLoWx2BSpkiCb?= =?us-ascii?Q?/xozyhBXbB233r/nXgAc7q9WJtG6EjGTu7d4PnuKs5oTzDnIH+/5sRpgkN2M?= =?us-ascii?Q?FAcu0vR3HqTXLz7uuQzpoqN5STePq8zBrtpVMA2CJatp1d+mLUdQpT2cbAEx?= =?us-ascii?Q?F345cAmYn/IunoigeNmhUcqdYtMYivZqB6qIDqH2iy1u6uhfAPcisD61bL3W?= =?us-ascii?Q?vVSlOAmodX9k/k8fIiB7+eezSOzblRdHMVn5lwr/kR0l3NlgSBCGpHpK5V56?= =?us-ascii?Q?PdswKAkMw79CcraO4CsoaFwmzfSJC3evI4KHR2h6y+k3RbRxAVviA803wBC3?= =?us-ascii?Q?278dAq6MnifCmTIwVeMuPibFTmW7Q1f2RXFCyzeOTaAuvfb0l/bH0Xv4FI85?= =?us-ascii?Q?ChuEtq5xF3qFspo6cJduGKBbl7FnH2dyRL/Soyw5DxRztFh8/3P+J+fxOwCv?= =?us-ascii?Q?TMRsfeK+EruQgA2f9Ii/6Ydy8gMQoZA3gPULQkPC8u1EhgmtwW/eQ1G8n84M?= =?us-ascii?Q?q1CdjwRam6+3Md3dZ9/UUNDu28HlVzfvFhW1kZ8Ga/6Gtz0kF+DqnZVUQ57l?= =?us-ascii?Q?YEzs6L+fwRYklzOvCwpLHsX9O20a+wJwnwyRxjXpGAtkso7qHgZ79f+cb6uj?= =?us-ascii?Q?kU36jNYj45sbOnFEPpv35RPJTAXU1F5W5qEKNy72a7VVkemZlKh38SEctU0V?= =?us-ascii?Q?sbqCtCHSQT24mWNLr7jsk3AgnZCsFY+La/DcJ/3A3lA46YE0p3Rhkr1uvZMA?= =?us-ascii?Q?of8uVbHHsPWW0awPpLbrDxvwgl2Ka66xksZKLC66N8tfoegescTYzl2BAvjH?= =?us-ascii?Q?nr5ZpByR1M14Qi40xAqEUsgokm3Yu0Ldu03U/j7xhWsNOXvfsAWqmGobVSNK?= =?us-ascii?Q?NGMNfPg6YiOu5+ZsDzUTefpQGpSjtakZhYViItbTVvr0UIMlypotjsPmKK0c?= =?us-ascii?Q?um9m/CopfKLJ7Bhd2cHJdi73AiNI5YoSiY2+nnlZvTndwbI7whOCuGaXgc7v?= =?us-ascii?Q?IS6mHo1lveRc7IBnPBOJXamuSzOEH2vIIaIFE1iatSWpbmH5gyKIG1/qTYLn?= =?us-ascii?Q?KawJyOnqOfFChTlfzUE8jdx7WHlmxaeaabeLMd1o/JfOzXl1DyiZdeObgz87?= =?us-ascii?Q?r9/8q+vApeLL6SsUqyJtx08+zZ/auxDc3ECR4A6KeJSipg53ss2ZCFdzcPNC?= =?us-ascii?Q?7txCCd/WcK14cVwzDiLY7o6RnthgI6mVN1V+szHrE0rRxtmmj9WLFffCjwLH?= =?us-ascii?Q?bgb6b7pCzACi4CGTzSKN9N0vDFl4FiAR03ux5sdsvUC0j5o/eM0ShjLLhTJt?= =?us-ascii?Q?3dz8WyWdogMPTuOKtRHQnbDGwGLiyiyo4lxtOxseSvZaS2VfzAvK5s87t+F8?= =?us-ascii?Q?Ua50hVih4dV8/4VsNv+tHnVV1Bi6wuKRL5CVhXdhy6qxrqWDRsJr?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 01c8c2c6-398c-49aa-076f-08de8568c344 X-MS-Exchange-CrossTenant-AuthSource: PH0PR12MB8800.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Mar 2026 03:36:53.3015 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: LrC1X6S6NFaaBD++c96ZhDdQboM2ZJGG+GoFLwbCszFeOd1JBPxVHoskUClov075ByHtPCF2rrCjtsAB9QaXiA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB8199 Content-Type: text/plain; charset="utf-8" This reverts commit a9dadc1c512807f955f0799e85830b420da47932. The commit message states:=20 When called from xive_irq_startup(), the size of the cpumask can be larger than nr_cpu_ids. This can result in a WARN_ON. [...] This happens because we're being called with our affinity mask set to irq_default_affinity. That in turn was populated using cpumask_setall(), which sets NR_CPUs worth of bits, not nr_cpu_ids worth. Finally cpumask_weight() will return > nr_cpu_ids when passed a mask which has > nr_cpu_ids bits set. In modern kernel, cpumask_weight() can't return > nr_cpu_ids. In inline case, cpumask_setall() explicitly clears all bits above nr_cpu_ids, see commit 63355b9884b3 ("cpumask: be more careful with 'cpumask_setall()'"). So, despite that cpumask_weight() is passed with small_cpumask_bits, which is NR_CPUS in this case, it can't count over the nr_cpu_ids. In outline case, cpumask_setall() may set bits beyond the limit up to the next byte alignment, but in this case small_cpumask_bits is wired to nr_cpu_ids, thus making overcounting impossible. Signed-off-by: Yury Norov Reviewed-by: Mukesh Kumar Chaurasiya (IBM) Tested-by: Mukesh Kumar Chaurasiya (IBM) --- I've added some explicit tests for cpumask_weight() to make sure: https://lore.kernel.org/all/20260319004349.849281-1-ynorov@nvidia.com/ arch/powerpc/sysdev/xive/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/c= ommon.c index e1a4f8a97393..e91ec9036ad8 100644 --- a/arch/powerpc/sysdev/xive/common.c +++ b/arch/powerpc/sysdev/xive/common.c @@ -551,7 +551,7 @@ static int xive_find_target_in_mask(const struct cpumas= k *mask, int cpu, first, num, i; =20 /* Pick up a starting point CPU in the mask based on fuzz */ - num =3D min_t(int, cpumask_weight(mask), nr_cpu_ids); + num =3D cpumask_weight(mask); first =3D fuzz % num; =20 /* Locate it */ --=20 2.43.0 From nobody Mon Apr 6 16:12:46 2026 Received: from CY7PR03CU001.outbound.protection.outlook.com (mail-westcentralusazon11010057.outbound.protection.outlook.com [40.93.198.57]) (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 C492737B40B for ; Thu, 19 Mar 2026 03:36:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.198.57 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773891421; cv=fail; b=hR0S8DGhGMvkef76cxaKczc96DHLXSsYemTgtghbKa7ZpENjrLVzHBh7V6ZoYaflEu/g+WsLKhmMqPTdegdZM1654vZxY+uY2y0x7JTH3XXqytPkiWaw2dFj55xnKDhzal6WFk4O/OOR57PMbU4bv6vwchTKZDJoIqEjfR5NgVI= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773891421; c=relaxed/simple; bh=OPBrnuSobKMrlhbJSxUs6YtR8NSlXQMYkXaBe9f2klc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=fSBgWqqI4Do483JH1YOF6tIWJeVKaER+xglzkoViiAb8PG+6EwvjZEsIr1edO2NeX3a7b+WBHvI7ERBLJpN0otAEJlYMPPm3c6FZBeEB8sbEYzB1RyIdpdz7aS7q5TLKabAKJP+RaFJlJxb9zLRg2TdRpwp/BoH6ZGzRSb03jlc= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=Rzd51ag+; arc=fail smtp.client-ip=40.93.198.57 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="Rzd51ag+" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=X9cEGQ5zzv/AaGIdrjpGW5/yAx/cphHkdRi6hhhOND7X7en++157us/irxz6Cmw2+8jqoA+QFfOIkNnB1qkhDwrGgpqNUlmlBq0Ynxt+3GFLBGmeQvoZ42D6tNEAE0IIVeOBhB5SvZ99cv8Dq8waT+Wubahu2Zol+JbsuUE+oSZldvXt76fcI0TP07kWxVd5o9A2bTQBMSpPIO/Ps66tXjLPAhGnLfLuah+GGos8x76O57koFXCyTkTKi0+iZtvIIdY7KOdTP6uxS5pb5ZycgYuEd9DKluvARKZj+mjrYFQcjSPP/Y1SpOUz2cUckBguUYBg/RPreXUJF5UY8SAYGA== 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=3IER9p+mDI1F3D6BQZH4KGfcsMhix8+8DRdKC5N0HzU=; b=VQ/JQ1WMtIF/wjb9YUaWnnC1timE4OKrrr5LfUshEpJMYu9r8IfzQLf5hHmZ98soZtC52X0bNCB010yE/DtZbY+T/S0u9+F8KNjIeDrGafDe4ftARNRnkcEGmzq1sUrQcLn5oKoaFi0Xl8bfpARXB1F8TcoraR1RFFylRIcIVJKqrXz75zAH+eud+n5/SxqphkDHfymuoJQExUDXh29Lx9o+INhcDJf0zH2B9nRKbQShVC0X48vUJr0D5HQkzuO/t9nAh9+lYPE2cNS4w6hiN9W7cYmhlcT/KqLJUsJAOoa1Kk6ciZqYyyB5U6bSXFOtf1+9oQ5wyeT1LBpDel+3Ow== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=3IER9p+mDI1F3D6BQZH4KGfcsMhix8+8DRdKC5N0HzU=; b=Rzd51ag+zJwGJhb7tiNYkVUk+65HOVhAxRXlrtS9GT6F2jHH6eLlOfeg5M39id1WeFFiZGlE8qoqObWIezELhU8q4SNwxSsEo6WupQERuB/khQ5rX4AZY3znhqnU8CwQ7xbNcUWe7pmE2JZLKd15fFyISW8pR4UfYPaChToTgrRFK1Fnh4k8j+rUCZQ/Vg8gdIT1MvIPntvHvU2EIc4/otyrRMbTn7Eiaa19uINy6HANq5KRA2eUgoX2tkPT9ExWxiLS90QeCiiP0foqDnTEaKAu7uBe6es/xCnduzkNPV31987JJxXDzlVmtHyTFjwCTHpqXtmhJRdnv4dmCl57SQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from PH0PR12MB8800.namprd12.prod.outlook.com (2603:10b6:510:26f::12) by DS0PR12MB8199.namprd12.prod.outlook.com (2603:10b6:8:de::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9745.9; Thu, 19 Mar 2026 03:36:55 +0000 Received: from PH0PR12MB8800.namprd12.prod.outlook.com ([fe80::f79d:ddc5:2ad7:762d]) by PH0PR12MB8800.namprd12.prod.outlook.com ([fe80::f79d:ddc5:2ad7:762d%4]) with mapi id 15.20.9745.007; Thu, 19 Mar 2026 03:36:55 +0000 From: Yury Norov To: Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Thomas Gleixner , Nam Cao , "Jiri Slaby (SUSE)" , Yury Norov , Kees Cook , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Cc: Linus Torvalds Subject: [PATCH 2/2] powerpc/xive: rework xive_find_target_in_mask() Date: Wed, 18 Mar 2026 23:36:46 -0400 Message-ID: <20260319033647.881246-3-ynorov@nvidia.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260319033647.881246-1-ynorov@nvidia.com> References: <20260319033647.881246-1-ynorov@nvidia.com> Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: BN0PR04CA0048.namprd04.prod.outlook.com (2603:10b6:408:e8::23) To PH0PR12MB8800.namprd12.prod.outlook.com (2603:10b6:510:26f::12) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH0PR12MB8800:EE_|DS0PR12MB8199:EE_ X-MS-Office365-Filtering-Correlation-Id: fb84cb08-3a08-4a82-46d3-08de8568c483 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|10070799003|366016|22082099003|18002099003|56012099003|921020; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH0PR12MB8800.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(376014)(10070799003)(366016)(22082099003)(18002099003)(56012099003)(921020);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?jQFkHFMor5Q5HKNv8Ubp9NPnphVmN3yc7qjw4LqfA3SOT6doZmb+Kh7igb+7?= =?us-ascii?Q?ae0dxTmFppSFOPAY5HPwZlsKaVk1vK1V5gyY+OzMY1iKQjD1Iu0lP9DTOLy9?= =?us-ascii?Q?N0QWCVGBD4052Dp8tuNLntWK7z9uq+hD5WowmHwZEHVKG0xWTmj2yIfTXqtD?= =?us-ascii?Q?6IelF96Nr2mIgMF3QTQ83Yxq8VXqaZ2pSIp5C5dNfpgMKLQKplWG3cvmoBk+?= =?us-ascii?Q?HysMo9aWjVHqB/nVevZvteRGoqux6GVUU4S90Xnz+DMoH9d8Zj2TGydjdKhF?= =?us-ascii?Q?QTRkp90lWUhKu7ie90b/kQMt7FNk84wkAP6+kaexXTaduCWYaPmmL8B5T0KE?= =?us-ascii?Q?HfDljUodhpJKEvEjzkWN3pviIg+o4mhlSPJV5t2VKDWsJg3cfcADNs3VyUYt?= =?us-ascii?Q?4Ia3smUju9mINomWwXk2As6OTYcE1Uww032tYpLr1A/eq2uH1BMRmQcinySo?= =?us-ascii?Q?wRm5fq1x/htNQcr0YvSA4+bChkYy+8kJR7Hi+5YdEr00mfM5d4SUiA4yxeIX?= =?us-ascii?Q?jS0idaZX+SC3dct1X6faeCFKuw3FDxSegDS52QD4YYFBTP4nzRA7GzxSuNsi?= =?us-ascii?Q?hr31aKXw9GTwrA8NcV+utmlTSxKUqHDDj3QGgu6p6cXej+7/2Jd3gOnQJuHT?= =?us-ascii?Q?yUXVxfSEMlMP60pgxb3jp13isCGZ6SArY+4u++gUAW53Vu34NzPJQUxgTIb0?= =?us-ascii?Q?M8CflzJNGrdaU+Filw0/vKnET0kNri1eYdJJFAOfixX1ynxbKkuf6Qg3Sn2G?= =?us-ascii?Q?P5kTfKVSSjB60fr21N7DTAfLD7W6PMAbMvZS3XCsBdxJLJ7tI5jz4ijPh664?= =?us-ascii?Q?xzq/9hYt+zmGvqQS0YHRgNDiHwOIDGMGaDZikbz1Qj6A8jMHZOWwb1r2pONF?= =?us-ascii?Q?MJdo0xw0osCvjHGUGnxR825lOOHT+ylNOxGqoQOKyDxsFWVVwiIn91pCW+dK?= =?us-ascii?Q?jbA6lBIzuPunmYHdOmPXe+uEJ9hvRMNNWwdhHDyBgequtgaHaQrMi8RCgg9+?= =?us-ascii?Q?DZNn7n367kkkAY64GEBG/DwqKpMJmytjCljmVeieAnSRxkV7sz+xFc/kPZ7O?= =?us-ascii?Q?0wZIq/Z8FesMhHa+0Rpe7nsYKWY/9LbBeCG3S9jTuLjynMP+cv5pFq15sPum?= =?us-ascii?Q?Q+5sKZ6l+N8FdofTjNpJ3EJetbz5KXJUZS1POOJo1GdgR3PHFDHOkr9+JzqX?= =?us-ascii?Q?roY57cgaCOa5lfcnQtSKLDUupUYNHsn7n5Ujk+xPXDsgCsyt08m8BtebAZZb?= =?us-ascii?Q?qQzEFxtBu0ZdYiSXX00rZK9YAfvG5SSUyI+WPZdUdF0aBqf3BwBWrwTCyOVc?= =?us-ascii?Q?X+MvO5RR1q/muR61AcZkEE1MzU/yRStmUaA7NdrKuMpsFDkWAnF6XLgCg2oO?= =?us-ascii?Q?iVGO98Q8gzTqWyhTIZAK8Uy0uesVyI7iDlIeh8QaGhaO+TO1EuAVpNSfGCst?= =?us-ascii?Q?p5Lwya4q6zBYfDGFho46aL+qqyIx6CrT+OJjiB8GmUt0E6/aR4h/B5FxgR5T?= =?us-ascii?Q?4pxDKJXypAiV7la+REhWn4U3TyhV9c5/9LnaxAPLw7YsfrWJccftJukjVdEC?= =?us-ascii?Q?mpu5xVSrsUVetkO21dYvANn1ml+ETY6GwZHdNqh7+UYimH/OtG08PbutOxoe?= =?us-ascii?Q?jphpkxYNYv7QAzbzi8yR7J0hIpaYM62PkeZhu5fsWtW/njTsRkUJ9J6rWIwX?= =?us-ascii?Q?rnLwprTPOxPeVRXTmYj0vsJEufWCkNhdUgAO2NUimLEahOzSy9wYo/ZAytlS?= =?us-ascii?Q?kqtc2kTSAg+DFC92Y1WyCMak2Ilw85tTIckXBp5l09/Jc/r3Hx9R?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: fb84cb08-3a08-4a82-46d3-08de8568c483 X-MS-Exchange-CrossTenant-AuthSource: PH0PR12MB8800.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Mar 2026 03:36:55.4225 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Xoj4+WljdA1feVA6XfljvhixYAM36yarYFTyIcW4mHmVMB5JztQZUtWyUJF8Th1QPzKPbp2x+fcIm4Fze6Fx+A== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB8199 Content-Type: text/plain; charset="utf-8" Switch the function to using modern cpumask API and drop most of the housekeeping code. Notice, if first >=3D nr_cpu_ids, for_each_cpu_wrap() iterator behaves just like for_each_cpu(), i.e. begins from 0. So even if WARN_ON() is triggered, no special handling is needed. Signed-off-by: Yury Norov Reviewed-by: Mukesh Kumar Chaurasiya (IBM) Reviewed-by: Shrikanth Hegde Tested-by: Mukesh Kumar Chaurasiya (IBM) --- arch/powerpc/sysdev/xive/common.c | 31 ++++++------------------------- 1 file changed, 6 insertions(+), 25 deletions(-) diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/c= ommon.c index e91ec9036ad8..4e05f678e171 100644 --- a/arch/powerpc/sysdev/xive/common.c +++ b/arch/powerpc/sysdev/xive/common.c @@ -548,40 +548,21 @@ static void xive_dec_target_count(int cpu) static int xive_find_target_in_mask(const struct cpumask *mask, unsigned int fuzz) { - int cpu, first, num, i; + int cpu, first; =20 /* Pick up a starting point CPU in the mask based on fuzz */ - num =3D cpumask_weight(mask); - first =3D fuzz % num; - - /* Locate it */ - cpu =3D cpumask_first(mask); - for (i =3D 0; i < first && cpu < nr_cpu_ids; i++) - cpu =3D cpumask_next(cpu, mask); - - /* Sanity check */ - if (WARN_ON(cpu >=3D nr_cpu_ids)) - cpu =3D cpumask_first(cpu_online_mask); - - /* Remember first one to handle wrap-around */ - first =3D cpu; + fuzz %=3D cpumask_weight(mask); + first =3D cpumask_nth(fuzz, mask); + WARN_ON(first >=3D nr_cpu_ids); =20 /* * Now go through the entire mask until we find a valid * target. */ - do { - /* - * We re-check online as the fallback case passes us - * an untested affinity mask - */ + for_each_cpu_wrap(cpu, mask, first) { if (cpu_online(cpu) && xive_try_pick_target(cpu)) return cpu; - cpu =3D cpumask_next(cpu, mask); - /* Wrap around */ - if (cpu >=3D nr_cpu_ids) - cpu =3D cpumask_first(mask); - } while (cpu !=3D first); + } =20 return -1; } --=20 2.43.0