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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 59E50D7237B for ; Sun, 25 Jan 2026 22:46:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=YcdTkE927g+/FfCgvHIRPU5ZO1R359X5YDI7SQf4OO4=; b=UhInN7TRQN7c1KZB0aRzHLgm+8 ozw4IZVugd4cAY6LHMGSVLmZvYWhYeBNvgTIRbvP5LukgnfZZt4X4UXY0LKnttyUadRWBwCkgn3Qo yDfNuXs7zDbNcdCwaUPxlNZz2CGEbp+uYe14JQtWsq7w4WN+ysv90Yey5ercjY1J9RdR5R1qbkdCM TjklH0u7sgS3VG1U53imU+ZvNQk3GKxmA3WdcgNvy5d8CMn7cgoqS7aV4sKjaQVBBqgW+y0jrHmjz ueQLK1i8EXR3k14FV7Nd3o+Rnc9WywKf1PQNE4n4JF5WtzguFHTJhrSpghalnAENaYPjLQAjtT+7B 4eJiAAQg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vk8rs-0000000Bb0e-0tw1; Sun, 25 Jan 2026 22:46:04 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vk8rq-0000000Bazt-29VU for linux-arm-kernel@lists.infradead.org; Sun, 25 Jan 2026 22:46:03 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 04A00408D2; Sun, 25 Jan 2026 22:46:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A88EC16AAE; Sun, 25 Jan 2026 22:45:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769381160; bh=vPL8EzXKWq9iiIp5kuYoia41/85wMoYaNYnO6c8sEhk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FIWgU7+pr7+ckwb83DyKxDiWT8xbe7CLrxGuGRjBUui3ebqjTplaAEWc1SnTKrjOG tUx+pdCeJFih0IMyujpdXJcHTYc5m6E+TsbZUkcYq0FjizUFEUOr5uKfn1ANgV8x3c iVZKrZlS1Txl44jkj+YbP5PDaSiE866VyLyaP3azWSwzmGZ8ZkjD5zVumV8c6k8I2E br5lPpen+XXuYE5ErnUP87vKq0rH5MzUQOK/Wzr6hGKGNE5Rz+Nyoss94n5SFzlEft rkDsNXhbh/uSNRerB1QWLMq7i4T11QBlyJZ2emnty4QgtX4wjKvHxpfQ7H7fWu5r3J +QCJLEqLO6GZw== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Andrew Morton , Bjorn Helgaas , Catalin Marinas , Chen Ridong , Danilo Krummrich , "David S . Miller" , Eric Dumazet , Gabriele Monaco , Greg Kroah-Hartman , Ingo Molnar , Jakub Kicinski , Jens Axboe , Johannes Weiner , Lai Jiangshan , Marco Crivellari , Michal Hocko , Muchun Song , Paolo Abeni , Peter Zijlstra , Phil Auld , "Rafael J . Wysocki" , Roman Gushchin , Shakeel Butt , Simon Horman , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , Will Deacon , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH 01/33] PCI: Prepare to protect against concurrent isolated cpuset change Date: Sun, 25 Jan 2026 23:45:08 +0100 Message-ID: <20260125224541.50226-2-frederic@kernel.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20260125224541.50226-1-frederic@kernel.org> References: <20260125224541.50226-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260125_144602_592910_BE34B3A4 X-CRM114-Status: GOOD ( 17.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org HK_TYPE_DOMAIN will soon integrate cpuset isolated partitions and therefore be made modifiable at runtime. Synchronize against the cpumask update using RCU. The RCU locked section includes both the housekeeping CPU target election for the PCI probe work and the work enqueue. This way the housekeeping update side will simply need to flush the pending related works after updating the housekeeping mask in order to make sure that no PCI work ever executes on an isolated CPU. This part will be handled in a subsequent patch. Signed-off-by: Frederic Weisbecker Acked-by: Bjorn Helgaas --- drivers/pci/pci-driver.c | 47 ++++++++++++++++++++++++++++++++-------- 1 file changed, 38 insertions(+), 9 deletions(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 7c2d9d596258..a6111140755c 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -302,9 +302,8 @@ struct drv_dev_and_id { const struct pci_device_id *id; }; -static long local_pci_probe(void *_ddi) +static int local_pci_probe(struct drv_dev_and_id *ddi) { - struct drv_dev_and_id *ddi = _ddi; struct pci_dev *pci_dev = ddi->dev; struct pci_driver *pci_drv = ddi->drv; struct device *dev = &pci_dev->dev; @@ -338,6 +337,19 @@ static long local_pci_probe(void *_ddi) return 0; } +struct pci_probe_arg { + struct drv_dev_and_id *ddi; + struct work_struct work; + int ret; +}; + +static void local_pci_probe_callback(struct work_struct *work) +{ + struct pci_probe_arg *arg = container_of(work, struct pci_probe_arg, work); + + arg->ret = local_pci_probe(arg->ddi); +} + static bool pci_physfn_is_probed(struct pci_dev *dev) { #ifdef CONFIG_PCI_IOV @@ -362,34 +374,51 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev, dev->is_probed = 1; cpu_hotplug_disable(); - /* * Prevent nesting work_on_cpu() for the case where a Virtual Function * device is probed from work_on_cpu() of the Physical device. */ if (node < 0 || node >= MAX_NUMNODES || !node_online(node) || pci_physfn_is_probed(dev)) { - cpu = nr_cpu_ids; + error = local_pci_probe(&ddi); } else { cpumask_var_t wq_domain_mask; + struct pci_probe_arg arg = { .ddi = &ddi }; if (!zalloc_cpumask_var(&wq_domain_mask, GFP_KERNEL)) { error = -ENOMEM; goto out; } + + INIT_WORK_ONSTACK(&arg.work, local_pci_probe_callback); + + /* + * The target election and the enqueue of the work must be within + * the same RCU read side section so that when the workqueue pool + * is flushed after a housekeeping cpumask update, further readers + * are guaranteed to queue the probing work to the appropriate + * targets. + */ + rcu_read_lock(); cpumask_and(wq_domain_mask, housekeeping_cpumask(HK_TYPE_WQ), housekeeping_cpumask(HK_TYPE_DOMAIN)); cpu = cpumask_any_and(cpumask_of_node(node), wq_domain_mask); + if (cpu < nr_cpu_ids) { + schedule_work_on(cpu, &arg.work); + rcu_read_unlock(); + flush_work(&arg.work); + error = arg.ret; + } else { + rcu_read_unlock(); + error = local_pci_probe(&ddi); + } + free_cpumask_var(wq_domain_mask); + destroy_work_on_stack(&arg.work); } - - if (cpu < nr_cpu_ids) - error = work_on_cpu(cpu, local_pci_probe, &ddi); - else - error = local_pci_probe(&ddi); out: dev->is_probed = 0; cpu_hotplug_enable(); -- 2.51.1