[PATCH 4.19 097/146] x86/speculation: Remove redundant arch_smt_update() invocation

From: Greg Kroah-Hartman
Date: Thu Apr 16 2020 - 09:36:19 EST


From: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: <konrad.wilk@xxxxxxxxxx>
Cc: <dwmw@xxxxxxxxxxxx>
Cc: <bp@xxxxxxx>
Cc: <srinivas.eeda@xxxxxxxxxx>
Cc: <peterz@xxxxxxxxxxxxx>
Cc: <hpa@xxxxxxxxx>
Link: https://lkml.kernel.org/r/e2e064f2-e8ef-42ca-bf4f-76b612964752@default
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
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)))