linux-kernel - [patch 04/12] clockevent unbind: use smp_call_func_single

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Message-ID: <20240206185709.928420669@redhat.com>
Date: Tue, 06 Feb 2024 15:49:15 -0300
From: Marcelo Tosatti <mtosatti@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: Daniel Bristot de Oliveira <bristot@...nel.org>,
 Juri Lelli <juri.lelli@...hat.com>,
 Valentin Schneider <vschneid@...hat.com>,
 Frederic Weisbecker <frederic@...nel.org>,
 Leonardo Bras <leobras@...hat.com>,
 Peter Zijlstra <peterz@...radead.org>,
 Thomas Gleixner <tglx@...utronix.de>,
 Marcelo Tosatti <mtosatti@...hat.com>
Subject: [patch 04/12] clockevent unbind: use smp_call_func_single_fail

Convert clockevents_unbind from smp_call_function_single
to smp_call_func_single_fail, which will fail in case
the target CPU is tagged as block interference CPU.

Signed-off-by: Marcelo Tosatti <mtosatti@...hat.com>

Index: linux-isolation/kernel/time/clockevents.c
===================================================================
--- linux-isolation.orig/kernel/time/clockevents.c
+++ linux-isolation/kernel/time/clockevents.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/smp.h>
 #include <linux/device.h>
+#include <linux/sched/isolation.h>
 
 #include "tick-internal.h"
 
@@ -416,9 +417,14 @@ static void __clockevents_unbind(void *a
  */
 static int clockevents_unbind(struct clock_event_device *ced, int cpu)
 {
+	int ret, idx;
 	struct ce_unbind cu = { .ce = ced, .res = -ENODEV };
 
-	smp_call_function_single(cpu, __clockevents_unbind, &cu, 1);
+	idx = block_interf_srcu_read_lock();
+	ret = smp_call_function_single_fail(cpu, __clockevents_unbind, &cu, 1);
+	block_interf_srcu_read_unlock(idx);
+	if (ret)
+		return ret;
 	return cu.res;
 }