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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C26A1C43327 for ; Fri, 3 Jul 2026 01:00:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2543F6B0139; Thu, 2 Jul 2026 21:00:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1B4116B0144; Thu, 2 Jul 2026 21:00:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EFB876B013F; Thu, 2 Jul 2026 21:00:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id C11936B013B for ; Thu, 2 Jul 2026 21:00:44 -0400 (EDT) Received: from smtpin12.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 933AC1C6E8B for ; Thu, 2 Jul 2026 17:54:45 +0000 (UTC) X-FDA: 84944586930.12.4E3E9B2 Received: from pdx-out-013.esa.us-west-2.outbound.mail-perimeter.amazon.com (pdx-out-013.esa.us-west-2.outbound.mail-perimeter.amazon.com [34.218.115.239]) by imf15.hostedemail.com (Postfix) with ESMTP id 7459AA0007 for ; Thu, 2 Jul 2026 17:54:43 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=amazon.de header.s=amazoncorp2 header.b=aKxabhML; spf=pass (imf15.hostedemail.com: domain of "prvs=6363c8db2=sakacpav@amazon.de" designates 34.218.115.239 as permitted sender) smtp.mailfrom="prvs=6363c8db2=sakacpav@amazon.de"; dmarc=pass (policy=quarantine) header.from=amazon.de ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1783014883; b=mxsNvzkMisuSp7/6dd1Y9DSVG5uMtyz8MUdSFbHPK7HICj+GSD3ZnlyiVSWqWvmIP33yd8 7CA+mb90GnHxzJvcWNb8pAAfH7JD+IeR/Kkjg1PE223NBEvv5QNUJL8Fblg8p9rW7FjiIR mLwsih1BIf2JQLKRFNALU4Gch2uQ/08= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1783014883; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=i8x4rQZI3wGrMps1gx7J+LUAbzJ5YVpPGmgWVMyrcn0=; b=TeNYLkm4311ku+A1HsGkQ4G4cpeNYlsp6/LoNaRBP04xGvt1MwF0oI/iVKXtDSNscLHcPx ebpzQdmUXXMSxfSM7OEc9mMdxE/uzvZD3qNVUXk8ElFcFdV4G0obmtBUGxQ+YDPH+qquwz ocvUVdXxQCO7MXEl3fwpyc3maulQhdg= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=amazon.de header.s=amazoncorp2 header.b=aKxabhML; spf=pass (imf15.hostedemail.com: domain of "prvs=6363c8db2=sakacpav@amazon.de" designates 34.218.115.239 as permitted sender) smtp.mailfrom="prvs=6363c8db2=sakacpav@amazon.de"; dmarc=pass (policy=quarantine) header.from=amazon.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazoncorp2; t=1783014883; x=1814550883; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=i8x4rQZI3wGrMps1gx7J+LUAbzJ5YVpPGmgWVMyrcn0=; b=aKxabhMLDD08J9yJ2+3GrKIRKMZeebEa1UkxmAwQS11ulZUFxkxDmgP2 FPsrS8aAFc4ZmJKfdCMFTRcFOepXqbli9sWXSj1E4HXwXS/MK4UZX8HMF EjLpNLl2h0oRaPAaV/5A3lU454iVC5ILo7wtjEIHXhjOMCkBfKGa3Gtla 2XC/zHEOvy8cTny65c3obFxxyrjh/aOjY7CrK4iWzeSf4XfY4JJnI92C9 +Oj5kCOOlt0QklJepaBI9zclfX46PJHY2KNeQ1Bp53Uj+NpudE5D/6l3Q RXgapli55kVKVKXzPLq/ltxzrv3V2NWVin9ObElaJKnXxt5OhALDMLz8n Q==; X-CSE-ConnectionGUID: sfChYbsLR7+K9S+0iXxigw== X-CSE-MsgGUID: eL0Sbib7Rj2GDrU/NWV6oA== X-IronPort-AV: E=Sophos;i="6.25,144,1779148800"; d="scan'208";a="22744903" Received: from ip-10-5-0-115.us-west-2.compute.internal (HELO smtpout.naws.us-west-2.prod.farcaster.email.amazon.dev) ([10.5.0.115]) by internal-pdx-out-013.esa.us-west-2.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jul 2026 17:54:40 +0000 Received: from EX19MTAUWB001.ant.amazon.com [205.251.233.104:15888] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.58.93:2525] with esmtp (Farcaster) id 1c94e942-37ba-4e7a-870c-87f2133b068d; Thu, 2 Jul 2026 17:54:39 +0000 (UTC) X-Farcaster-Flow-ID: 1c94e942-37ba-4e7a-870c-87f2133b068d Received: from EX19D001UWA001.ant.amazon.com (10.13.138.214) by EX19MTAUWB001.ant.amazon.com (10.250.64.248) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.43; Thu, 2 Jul 2026 17:54:39 +0000 Received: from dev-dsk-sakacpav-1a-480d1124.eu-west-1.amazon.com (172.19.96.155) by EX19D001UWA001.ant.amazon.com (10.13.138.214) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.43; Thu, 2 Jul 2026 17:54:36 +0000 From: Pavol Sakac To: Greg Kroah-Hartman , "Rafael J . Wysocki" , Danilo Krummrich , Tejun Heo CC: , , "David Woodhouse" , Pasha Tatashin , Mike Rapoport , Pratyush Yadav , "David Matlack" , Samiullah Khawaja , Alexander Graf , , , Subject: [RFC PATCH 11/14] vfio: opt vfio-dev and VFIO group devices into sysfs_lazy Date: Thu, 2 Jul 2026 19:51:11 +0200 Message-ID: <20260702175114.24659-7-sakacpav@amazon.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260702175114.24659-1-sakacpav@amazon.de> References: <20260702174033.32116-1-sakacpav@amazon.de> <20260702175114.24659-1-sakacpav@amazon.de> MIME-Version: 1.0 X-Originating-IP: [172.19.96.155] X-ClientProxiedBy: EX19D042UWB003.ant.amazon.com (10.13.139.135) To EX19D001UWA001.ant.amazon.com (10.13.138.214) Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 7459AA0007 X-Rspam-User: X-Stat-Signature: 764j9pzgj1ks899diuw9qt34j8tir4es X-HE-Tag: 1783014883-671720 X-HE-Meta: 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 h4/8Vff+ 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Call device_set_sysfs_lazy() on vfio_device->device (vfio-dev/) and on the VFIO group's struct device (vfio//) before device_add(). With opt-in, vfio-dev directories materialise their attribute_groups (vfio_dev_groups + drvdata->ops->dev_groups) on first access via the sysfs lookup path instead of eagerly at device_add(). The VFIO group device's flat attrs follow the same deferral. Removes the eager creation cost on platforms with thousands of VFs assigned to VFIO containers. No userspace ABI change. Cc: Alex Williamson Cc: Jason Gunthorpe Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman Cc: Danilo Krummrich Cc: driver-core@lists.linux.dev Cc: linux-api@vger.kernel.org Assisted-by: Claude:claude-opus-4.7 Signed-off-by: Pavol Sakac --- drivers/vfio/group.c | 5 +++++ drivers/vfio/vfio_main.c | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c index b2299e5bc6df3..aa7e0033b96e8 100644 --- a/drivers/vfio/group.c +++ b/drivers/vfio/group.c @@ -533,6 +533,11 @@ static struct vfio_group *vfio_group_alloc(struct iommu_group *iommu_group, group->dev.devt = MKDEV(MAJOR(vfio.group_devt), minor); group->dev.class = &vfio_class; group->dev.release = vfio_group_release; + /* Defer per-device attrs to first kernfs access; userspace reads via ioctl. */ + if (device_set_sysfs_lazy(&group->dev)) { + put_device(&group->dev); + return ERR_PTR(-ENOMEM); + } cdev_init(&group->cdev, &vfio_group_fops); group->cdev.owner = THIS_MODULE; diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index 6222376ab6ab5..ab90279c44bd0 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -306,6 +306,11 @@ static int vfio_init_device(struct vfio_device *device, struct device *dev, goto out_uninit; } + /* Allocated before device_initialize() so out_uninit unwind frees it. */ + ret = device_set_sysfs_lazy(&device->device); + if (ret) + goto out_uninit; + device_initialize(&device->device); device->device.release = vfio_device_release; device->device.class = &vfio_device_class; -- 2.47.3 Amazon Web Services Development Center Germany GmbH Tamara-Danz-Str. 13 10243 Berlin Geschaeftsfuehrung: Christof Hellmis, Andreas Stieger Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B Sitz: Berlin Ust-ID: DE 365 538 597