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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@kernel.org>, Aaron Tomlin <atomlin@atomlin.com>
Subject: [PATCH] genirq/affinity: Remove cpus_read_lock() while reading cpu_possible_mask
Date: Wed, 1 Apr 2026 14:13:34 +0200	[thread overview]
Message-ID: <20260401121334.xeMOSC1v@linutronix.de> (raw)

cpu_possible_mask is set early during boot based on information from the
firmware. After that it remains read only and is never changed.
Therefore there is no need to acquire CPU-hotplug locks while reading
it.

Remove cpus_read_*() while accessing cpu_possible_mask.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 kernel/irq/affinity.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index 85c45cfe72238..78f2418a89252 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -115,13 +115,10 @@ unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec,
 	if (resv > minvec)
 		return 0;
 
-	if (affd->calc_sets) {
+	if (affd->calc_sets)
 		set_vecs = maxvec - resv;
-	} else {
-		cpus_read_lock();
+	else
 		set_vecs = cpumask_weight(cpu_possible_mask);
-		cpus_read_unlock();
-	}
 
 	return resv + min(set_vecs, maxvec - resv);
 }
-- 
2.53.0


             reply	other threads:[~2026-04-01 12:13 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-01 12:13 Sebastian Andrzej Siewior [this message]
2026-04-01 14:15 ` [tip: irq/core] genirq/affinity: Remove cpus_read_lock() while reading cpu_possible_mask tip-bot2 for Sebastian Andrzej Siewior
2026-04-03  0:26 ` [PATCH] " Aaron Tomlin

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