linux-kernel - [PATCH 4.19 097/146] x86/speculation: Remove redundant arch_smt

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Date:   Thu, 16 Apr 2020 15:23:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Zhenzhong Duan <zhenzhong.duan@...cle.com>,
        Thomas Gleixner <tglx@...utronix.de>, konrad.wilk@...cle.com,
        dwmw@...zon.co.uk, bp@...e.de, srinivas.eeda@...cle.com,
        peterz@...radead.org, hpa@...or.com,
        Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH 4.19 097/146] x86/speculation: Remove redundant arch_smt_update() invocation

From: Zhenzhong Duan <zhenzhong.duan@...cle.com>

commit 34d66caf251df91ff27b24a3a786810d29989eca upstream.

With commit a74cfffb03b7 ("x86/speculation: Rework SMT state change"),
arch_smt_update() is invoked from each individual CPU hotplug function.

Therefore the extra arch_smt_update() call in the sysfs SMT control is
redundant.

Fixes: a74cfffb03b7 ("x86/speculation: Rework SMT state change")
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...cle.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: <konrad.wilk@...cle.com>
Cc: <dwmw@...zon.co.uk>
Cc: <bp@...e.de>
Cc: <srinivas.eeda@...cle.com>
Cc: <peterz@...radead.org>
Cc: <hpa@...or.com>
Link: https://lkml.kernel.org/r/e2e064f2-e8ef-42ca-bf4f-76b612964752@default
Cc: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 kernel/cpu.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2070,10 +2070,8 @@ int cpuhp_smt_disable(enum cpuhp_smt_con
 		 */
 		cpuhp_offline_cpu_device(cpu);
 	}
-	if (!ret) {
+	if (!ret)
 		cpu_smt_control = ctrlval;
-		arch_smt_update();
-	}
 	cpu_maps_update_done();
 	return ret;
 }
@@ -2084,7 +2082,6 @@ int cpuhp_smt_enable(void)
 
 	cpu_maps_update_begin();
 	cpu_smt_control = CPU_SMT_ENABLED;
-	arch_smt_update();
 	for_each_present_cpu(cpu) {
 		/* Skip online CPUs and CPUs on offline nodes */
 		if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))