From: Thomas Gleixner Date: Thu, 15 Jun 2023 20:33:54 +0000 (+0200) Subject: x86/smp: Remove pointless wmb()s from native_stop_other_cpus() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2affa6d6db28855e6340b060b809c23477aa546e;p=linux.git x86/smp: Remove pointless wmb()s from native_stop_other_cpus() The wmb()s before sending the IPIs are not synchronizing anything. If at all then the apic IPI functions have to provide or act as appropriate barriers. Remove these cargo cult barriers which have no explanation of what they are synchronizing. Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov (AMD) Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230615193330.378358382@linutronix.de --- diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index 935bc6562fa45..d842875f986fa 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -184,9 +184,6 @@ static void native_stop_other_cpus(int wait) cpumask_clear_cpu(cpu, &cpus_stop_mask); if (!cpumask_empty(&cpus_stop_mask)) { - /* sync above data before sending IRQ */ - wmb(); - apic_send_IPI_allbutself(REBOOT_VECTOR); /* @@ -208,9 +205,6 @@ static void native_stop_other_cpus(int wait) * CPUs to stop. */ if (!smp_no_nmi_ipi && !register_stop_handler()) { - /* Sync above data before sending IRQ */ - wmb(); - pr_emerg("Shutting down cpus with NMI\n"); for_each_cpu(cpu, &cpus_stop_mask)