From ad3c5d9224ffcd7b2e083f03441c6188d2bbef67 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 18 May 2021 11:17:28 +0200
Subject: [PATCH 01/14] perf/arm-cmn: 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>

Link: https://lore.kernel.org/r/20210518093118.277228577@linutronix.de
Signed-off-by: Will Deacon <will@kernel.org>

Upstream-Status: Backport [https://lore.kernel.org/r/20210518093118.277228577@linutronix.de]
Signed-off-by: Rupinderjit Singh <rupinderjit.singh@arm.com>
---
 drivers/perf/arm-cmn.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index 46defb1dcf86..38fa6f89d0bc 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -1162,7 +1162,7 @@ static int arm_cmn_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
 
 	perf_pmu_migrate_context(&cmn->pmu, cpu, target);
 	for (i = 0; i < cmn->num_dtcs; i++)
-		irq_set_affinity_hint(cmn->dtc[i].irq, cpumask_of(target));
+		irq_set_affinity(cmn->dtc[i].irq, cpumask_of(target));
 	cmn->cpu = target;
 	return 0;
 }
@@ -1222,7 +1222,7 @@ static int arm_cmn_init_irqs(struct arm_cmn *cmn)
 		if (err)
 			return err;
 
-		err = irq_set_affinity_hint(irq, cpumask_of(cmn->cpu));
+		err = irq_set_affinity(irq, cpumask_of(cmn->cpu));
 		if (err)
 			return err;
 	next:
@@ -1568,16 +1568,11 @@ static int arm_cmn_probe(struct platform_device *pdev)
 static int arm_cmn_remove(struct platform_device *pdev)
 {
 	struct arm_cmn *cmn = platform_get_drvdata(pdev);
-	int i;
 
 	writel_relaxed(0, cmn->dtc[0].base + CMN_DT_DTC_CTL);
 
 	perf_pmu_unregister(&cmn->pmu);
 	cpuhp_state_remove_instance(arm_cmn_hp_state, &cmn->cpuhp_node);
-
-	for (i = 0; i < cmn->num_dtcs; i++)
-		irq_set_affinity_hint(cmn->dtc[i].irq, NULL);
-
 	return 0;
 }
 
-- 
2.25.1