From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout08.his.huawei.com (canpmsgout08.his.huawei.com [113.46.200.223]) (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 1E0532877E5; Mon, 29 Dec 2025 03:24:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.223 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766978653; cv=none; b=RlcgOzTk6h660ISKxhs0EgxDLEWdx7vGqJ0x/HCcsyZ/R6QZyWl6W9nHwnuwM8kmOF1so6W07RTk8b29fOf97ONBEpBiVfpjw0Dde3UL1OZkKO1x17PyjkOS1YrFjxMVP8CHp3Y1o3XHw5QugNqS2IJtCKYkqcIwi6Rk3N0LzNI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766978653; c=relaxed/simple; bh=ZJEzZz24I4SkxEyQ42RbH6MATyuV3CWjO1JRtGv7kWg=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=N8MGeFERcxEwlX2n24O5rc2g3dpxi8fyEr8NV2lLd43uHTYr7gT9tUAvbJHU3lhiUYnKNvI5Tb0BCQ035yFqS+9vbgkGvjT6HIfu7rmuLSwSr5kpQ4ZcRRGTKuptO5PWmp88/reDoNSy8qrHZdsCuQM0Etk0RA5QfBJfNpiemsY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=S5oznL7E; arc=none smtp.client-ip=113.46.200.223 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="S5oznL7E" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=+BDGPe6Wz623mn9DQDdS+J7GvS2xhqJ99bp8antJarY=; b=S5oznL7E1P+omaU+fUcM+wvPVZ/3cp/IsoQKCRwXkrHP4luHaqG+eOUxh9smTTkbEqw7uNvL0 c4F1Wz+fPO5F6LWQgHy3huRbvjOsFw6aJ5tzPzxeXifnT01IAPtQc9PeSF0XS6pqphA89L2jlAL eTXaNu0tOj/1OwY7Cqz7TxY= Received: from mail.maildlp.com (unknown [172.19.163.163]) by canpmsgout08.his.huawei.com (SkyGuard) with ESMTPS id 4dfhLm6PbPzmVYJ; Mon, 29 Dec 2025 11:20:48 +0800 (CST) Received: from dggpemf100017.china.huawei.com (unknown [7.185.36.74]) by mail.maildlp.com (Postfix) with ESMTPS id 5B2D440565; Mon, 29 Dec 2025 11:23:59 +0800 (CST) Received: from [10.67.111.186] (10.67.111.186) by dggpemf100017.china.huawei.com (7.185.36.74) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 29 Dec 2025 11:23:57 +0800 Message-ID: Date: Mon, 29 Dec 2025 11:23:56 +0800 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.1.1 Subject: Re: [PATCH 01/33] PCI: Prepare to protect against concurrent isolated cpuset change To: Frederic Weisbecker , LKML CC: =?UTF-8?Q?Michal_Koutn=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 , , , , , , References: <20251224134520.33231-1-frederic@kernel.org> <20251224134520.33231-2-frederic@kernel.org> From: Zhang Qiao In-Reply-To: <20251224134520.33231-2-frederic@kernel.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepems100002.china.huawei.com (7.221.188.206) To dggpemf100017.china.huawei.com (7.185.36.74) Hi, Weisbecker， 在 2025/12/24 21:44, Frederic Weisbecker 写道: > 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 > --- > 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..786d6ce40999 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 }; > + > + INIT_WORK_ONSTACK(&arg.work, local_pci_probe_callback); > > if (!zalloc_cpumask_var(&wq_domain_mask, GFP_KERNEL)) { > error = -ENOMEM; If we return from here, arg.work will not be destroyed. > goto out; > } > + > + /* > + * 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(); >