From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f42.google.com (mail-wr1-f42.google.com [209.85.221.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7D4DF39B966 for ; Mon, 20 Apr 2026 13:12:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776690727; cv=none; b=NHqTTNpdwrWKbClZjsInxUxhkonmWjgK5HcM0pqD5wdbf1A1p7gujXKbIPSw8XGDwny3hkcDZ4UISYGxfeVzrkqenFz5XF4Smbr0w3DYiLLrZtlx4nNeaOi4hfPh+/XD/Xrirzx5dGZOs6FjAzuk4+rpJS6RJ62YapNKZeBJ348= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776690727; c=relaxed/simple; bh=unTlZmvymtrAosC1gc38VchUcqWpH3KjnweqTsHal+U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GOzKkDZr3whwP+keyZyqOmg9yLUrHbNwVMBYw0GyBEChzldnXvqz1G5MlHCqOIGdRZ3YlKm4/4fpr5qDpGKx1F+c0opSRBmb7lvvEGfX2nAXhgddcAFLj6kJ1BF51Bn6b3iMuaJBy8/cXYCkVYa0LCbEql7ZFApRcXKqcuCFafY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=UShMC9sP; arc=none smtp.client-ip=209.85.221.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="UShMC9sP" Received: by mail-wr1-f42.google.com with SMTP id ffacd0b85a97d-43fe62837baso1810217f8f.3 for ; Mon, 20 Apr 2026 06:12:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1776690725; x=1777295525; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=CD9/SaQbaCJB7OvL/7Y9DGnFoX5Sh5QHuy91IeKetc0=; b=UShMC9sPKIXAABkt2mxYVW3M3DS441d3L8BNgNeqUm8wTqC5qurMYG1DGn//6WVfuw gKhEL5iwKPVEjK4R+/+OpdX1Nj5vw4jVwusZ+SIHuJj3z+jsezJJjs3pNgUz/+LyqIlN XfszX3TksYhJpeLydcJUbnh8TbkHOIHZ14fkcq2UXA3qGE3MeRvOIrzAzGHU39uzKtjw kg6a0Oy+QGLODZIbK02gStk7xI9QGC9AhL5rPl+hRBfOCfIWYgq7PmZkzBTPhRSTlozZ RCdHPtmh7cFllmFCOdtrZflqEtcZCOEzuvoeJA4kbDDVwARqzqIlN1gMoauTc+tJ59QT Ftpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776690725; x=1777295525; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=CD9/SaQbaCJB7OvL/7Y9DGnFoX5Sh5QHuy91IeKetc0=; b=MlK2RYytLRWsHhOVMNFnEsQRJpJcnVPJRDVlRbfHK2yTaZb8Bk9l5rzUub5momiYW0 18DXafGgTg8ULWvGW4tIB5vnMv1mORBGj9avNV4rwxlHhsm08+9PlBj0t92TR+Q9PNt0 w8BLA1wDYj9OP3XWaZ6OMeS5xJldKLIhbnhZdbffTOi65Ykd3TwJzeh3ikUk5Sqk4BGd vsu3zqKmZcDaWwTlSlYnh2guyrNipwQwW63vc6KoWJBqmYAghQjKKxsyttCXO0lonvvE xU5BdWDrv1YDZMMtZ9xQjaHb1MFCxXLYXGp7Vv9Pv28zlKLDbp5sH4nQZ9J68FAfRrUC SScw== X-Forwarded-Encrypted: i=1; AFNElJ+K0Xlfg1wR5Jals1P89RbHsutHbrHVECesZ4BMmSaHqlcvErZM6l4yawVQXAI0FJckuh2JxzCOf3Zi@vger.kernel.org X-Gm-Message-State: AOJu0Yx0za5qsWWi6S2GpSfifaouNGfJnU3zmO4wNaS/oC0PyfdNg9bH TrtWfkdtl8n6AJgb8vBX1vkXo9Mw9oNxzS1umyMNGXw90Uqu0QpAKftO776sw56DynM= X-Gm-Gg: AeBDievKaJnLLsXyCUz67zXbNE86OA3QO4cFj2bQ2UoD4ETsxV9YOpLjQARnEirkdsb bqWCdC9wLCoUsHbHOQ4Z7F4VDAjOWam+iFZB73g9zrrbci6zK9aEhsxkn1UR/oKQ1/ehsgG6+N0 3QByEDg2rK/XA8CuNCLMPTodPGtaw4MzeH0MDMJ3bv77V+YaK8MrGeBkHuNiqS9GO6rzL898rhk yJ5kr5mvEZ4N4EbTz9d1k5WzektiFllzsirWz0VT6HGgqp82B7/Cm8SyBrDBQxJCuNxHEk3lTzP GT037jcQxvgqy+AHr5frkVBaRbHobtFsPxw8DP0BbZ8HDNLWu9L3tBNKUyLeSVwCnRVNA/XQnxk y9pxPJoqe0lqs8uX4765Sxo3UcYUyLCGV3SPC99npwFxphqyBoH0mvxorqXtDY75bctP89ZEHXm rYGjTKMOqQ6Rh4qAcP9+clpS+K7An4Kg+ofJkj9zg8Y4RzpQme/A== X-Received: by 2002:a05:6000:25c4:b0:43c:f52b:8003 with SMTP id ffacd0b85a97d-43fe3dfd332mr19870492f8f.36.1776690724775; Mon, 20 Apr 2026 06:12:04 -0700 (PDT) Received: from linux.fritz.box ([2a00:6d43:105:c401:e307:1a37:2e76:ce91]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43fe4e4d112sm32580385f8f.29.2026.04.20.06.12.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Apr 2026 06:12:03 -0700 (PDT) From: Marco Crivellari To: atomlin@atomlin.com Cc: James.Bottomley@HansenPartnership.com, MPT-FusionLinux.pdl@broadcom.com, aacraid@microsemi.com, akpm@linux-foundation.org, axboe@kernel.dk, bigeasy@linutronix.de, chandrakanth.patil@broadcom.com, chenridong@huawei.com, chjohnst@gmail.com, frederic@kernel.org, hare@suse.de, hch@lst.de, jinpu.wang@cloud.ionos.com, juri.lelli@redhat.com, kashyap.desai@broadcom.com, kbusch@kernel.org, kch@nvidia.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, liyihang9@h-partners.com, longman@redhat.com, martin.petersen@oracle.com, maz@kernel.org, megaraidlinux.pdl@broadcom.com, ming.lei@redhat.com, mingo@redhat.com, mpi3mr-linuxdrv.pdl@broadcom.com, mproche@gmail.com, mst@redhat.com, neelx@suse.com, nick.lange@gmail.com, peterz@infradead.org, ranjan.kumar@broadcom.com, ruanjinjie@huawei.com, sagi@grimberg.me, sathya.prakash@broadcom.com, sean@ashe.io, shivasharan.srikanteshwara@broadcom.com, sreekanth.reddy@broadcom.com, steve@abita.co, suganath-prabu.subramani@broadcom.com, sumit.saxena@broadcom.com, tglx@kernel.org, tom.leiming@gmail.com, vincent.guittot@linaro.org, virtualization@lists.linux.dev, wagi@kernel.org, yphbchou0911@gmail.com Subject: Re: [PATCH v11 03/13] lib/group_cpus: Add group_mask_cpus_evenly() Date: Mon, 20 Apr 2026 15:11:52 +0200 Message-ID: <20260420131152.243488-1-marco.crivellari@suse.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260416192942.1243421-4-atomlin@atomlin.com> References: <20260416192942.1243421-4-atomlin@atomlin.com> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi, Maybe I'm missing some background here, I noticed group_mask_cpus_evenly() is called inside irq_create_affinity_masks() and the "numgrps" it is this_vecs in the latter. Looking to group_cpus_evenly(), seems it is possible to have this_vecs equals to 0, indeed this function return NULL if numgrps == 0: >488 struct cpumask *group_cpus_evenly(unsigned int numgrps, unsigned int *nummasks) >489 { >[...] >495 >496 if (numgrps == 0) >497 return NULL; Without it, I guess the kmalloc() in `group_mask_cpus_evenly()` will return ZERO_SIZE_PTR: >+struct cpumask *group_mask_cpus_evenly(unsigned int numgrps, >+ const struct cpumask *mask, >+ unsigned int *nummasks) >+{ > > [...] > >+ masks = kcalloc(numgrps, sizeof(*masks), GFP_KERNEL); >+ if (!masks) >+ goto fail_node_to_cpumask; and this value is then passed to `__group_cpus_evenly()`. Should this check be added or it is not needed? Or maybe rely on `ZERO_OR_NULL_PTR()` ? Thanks! -- Marco Crivellari SUSE Labs