linux-kernel - [PATCH 20/33] PCI: Remove superfluous HK_TYPE

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Message-ID: <20251013203146.10162-21-frederic@kernel.org>
Date: Mon, 13 Oct 2025 22:31:33 +0200
From: Frederic Weisbecker <frederic@...nel.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Frederic Weisbecker <frederic@...nel.org>,
	Michal Koutný <mkoutny@...e.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Danilo Krummrich <dakr@...nel.org>,
	"David S . Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Gabriele Monaco <gmonaco@...hat.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Ingo Molnar <mingo@...hat.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Jens Axboe <axboe@...nel.dk>,
	Johannes Weiner <hannes@...xchg.org>,
	Lai Jiangshan <jiangshanlai@...il.com>,
	Marco Crivellari <marco.crivellari@...e.com>,
	Michal Hocko <mhocko@...e.com>,
	Muchun Song <muchun.song@...ux.dev>,
	Paolo Abeni <pabeni@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Phil Auld <pauld@...hat.com>,
	"Rafael J . Wysocki" <rafael@...nel.org>,
	Roman Gushchin <roman.gushchin@...ux.dev>,
	Shakeel Butt <shakeel.butt@...ux.dev>,
	Simon Horman <horms@...nel.org>,
	Tejun Heo <tj@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Vlastimil Babka <vbabka@...e.cz>,
	Waiman Long <longman@...hat.com>,
	Will Deacon <will@...nel.org>,
	cgroups@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-block@...r.kernel.org,
	linux-mm@...ck.org,
	linux-pci@...r.kernel.org,
	netdev@...r.kernel.org
Subject: [PATCH 20/33] PCI: Remove superfluous HK_TYPE_WQ check

It doesn't make sense to use nohz_full without also isolating the
related CPUs from the domain topology, either through the use of
isolcpus= or cpuset isolated partitions.

And now HK_TYPE_DOMAIN includes all kinds of domain isolated CPUs.

This means that HK_TYPE_KERNEL_NOISE (of which HK_TYPE_WQ is only an
alias) should always be a subset of HK_TYPE_DOMAIN.

Therefore sane configurations verify:

	HK_TYPE_KERNEL_NOISE | HK_TYPE_DOMAIN == HK_TYPE_DOMAIN

Simplify the PCI probe target election accordingly.

Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
---
 drivers/pci/pci-driver.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index ac86aaec8bcf..e731aaf28c76 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -384,16 +384,9 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
 	    pci_physfn_is_probed(dev)) {
 		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;
-			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
@@ -402,12 +395,9 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
 		 * 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);
+				      housekeeping_cpumask(HK_TYPE_DOMAIN));
+
 		if (cpu < nr_cpu_ids) {
 			struct workqueue_struct *wq = pci_probe_wq;
 
@@ -422,10 +412,9 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
 			error = local_pci_probe(&ddi);
 		}
 
-		free_cpumask_var(wq_domain_mask);
 		destroy_work_on_stack(&arg.work);
 	}
-out:
+
 	dev->is_probed = 0;
 	cpu_hotplug_enable();
 	return error;
-- 
2.51.0