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perf/arm-smmuv3: Use irq_set_affinity() 

The driver uses irq_set_affinity_hint() to set the affinity for the PMU
interrupts, which relies on the undocumented side effect that this function
actually sets the affinity under the hood.

Setting an hint is clearly not a guarantee and for these PMU interrupts an
affinity hint, which is supposed to guide userspace for setting affinity,
is beyond pointless, because the affinity of these interrupts cannot be
modified from user space.

Aside of that the error checks are bogus because the only error which is
returned from irq_set_affinity_hint() is when there is no irq descriptor
for the interrupt number, but not when the affinity set fails. That's on
purpose because the hint can point to an offline CPU.

Replace the mindless abuse with irq_set_affinity().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210518093118.603636289@linutronix.de
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Thomas Gleixner 2021-05-18 11:17:31 +02:00 committed by Will Deacon
parent 41ea281724
commit 2621054535
1 changed files with 3 additions and 7 deletions
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10
drivers/perf/arm_smmuv3_pmu.c
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@ -628,7 +628,7 @@ static int smmu_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
perf_pmu_migrate_context(&smmu_pmu->pmu, cpu, target);
smmu_pmu->on_cpu = target;
WARN_ON(irq_set_affinity_hint(smmu_pmu->irq, cpumask_of(target)));
WARN_ON(irq_set_affinity(smmu_pmu->irq, cpumask_of(target)));
return 0;
}
@ -839,15 +839,14 @@ static int smmu_pmu_probe(struct platform_device *pdev)
/* Pick one CPU to be the preferred one to use */
smmu_pmu->on_cpu = raw_smp_processor_id();
WARN_ON(irq_set_affinity_hint(smmu_pmu->irq,
cpumask_of(smmu_pmu->on_cpu)));
WARN_ON(irq_set_affinity(smmu_pmu->irq, cpumask_of(smmu_pmu->on_cpu)));
err = cpuhp_state_add_instance_nocalls(cpuhp_state_num,
&smmu_pmu->node);
if (err) {
dev_err(dev, "Error %d registering hotplug, PMU @%pa\n",
err, &res_0->start);
goto out_clear_affinity;
return err;
}
err = perf_pmu_register(&smmu_pmu->pmu, name, -1);
@ -866,8 +865,6 @@ static int smmu_pmu_probe(struct platform_device *pdev)
out_unregister:
cpuhp_state_remove_instance_nocalls(cpuhp_state_num, &smmu_pmu->node);
out_clear_affinity:
irq_set_affinity_hint(smmu_pmu->irq, NULL);
return err;
}
@ -877,7 +874,6 @@ static int smmu_pmu_remove(struct platform_device *pdev)
perf_pmu_unregister(&smmu_pmu->pmu);
cpuhp_state_remove_instance_nocalls(cpuhp_state_num, &smmu_pmu->node);
irq_set_affinity_hint(smmu_pmu->irq, NULL);
return 0;
}