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genirq: Take the proposed affinity at face value if force==true 

From: Marc Zyngier <maz@kernel.org>

commit c48c8b829d upstream.

Although setting the affinity of an interrupt to a set of CPUs that doesn't
have any online CPU is generally frowned apon, there are a few limited
cases where such affinity is set from a CPUHP notifier, setting the
affinity to a CPU that isn't online yet.

The saving grace is that this is always done using the 'force' attribute,
which gives a hint that the affinity setting can be outside of the online
CPU mask and the callsite set this flag with the knowledge that the
underlying interrupt controller knows to handle it.

This restores the expected behaviour on Marek's system.

Fixes: 33de0aa4ba ("genirq: Always limit the affinity to online CPUs")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/4b7fc13c-887b-a664-26e8-45aed13f048a@samsung.com
Link: https://lore.kernel.org/r/20220414140011.541725-1-maz@kernel.org

Signed-off-by: Luiz Capitulino <luizcap@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Luiz Capitulino 2022-11-28 17:08:35 +00:00 committed by Greg Kroah-Hartman
parent 9d90a2b98e
commit b56d6e5585
1 changed files with 8 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
kernel/irq/manage.c
View File

@ -267,10 +267,16 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
prog_mask = mask;
}
/* Make sure we only provide online CPUs to the irqchip */
/*
* Make sure we only provide online CPUs to the irqchip,
* unless we are being asked to force the affinity (in which
* case we do as we are told).
*/
cpumask_and(&tmp_mask, prog_mask, cpu_online_mask);
if (!cpumask_empty(&tmp_mask))
if (!force && !cpumask_empty(&tmp_mask))
ret = chip->irq_set_affinity(data, &tmp_mask, force);
else if (force)
ret = chip->irq_set_affinity(data, mask, force);
else
ret = -EINVAL;