No need to add spin_loc() and spin_unlock() for cpu_public - cpu_suspended

[Dongjiu Geng]

Hi,
     I see  cpu_public->cpu_suspended is protected by spinlock,  but I
see there is no concurrency problem for the cpu_public->cpu_suspended.
 check_events() is the only place to change cpu_public->cpu_suspended
variable， other CPU can not change is variable, also  check_events()
is
not preempted in the current CPU, because IRQ is masked in the current
CPU.  So there is no need to add spin_lock for
cpu_public->cpu_suspended variable.


static void check_events(struct public_per_cpu *cpu_public)
{
        bool reset = false;

        spin_lock(&cpu_public->control_lock);

        while (cpu_public->suspend_cpu) {
                cpu_public->cpu_suspended = true;

                spin_unlock(&cpu_public->control_lock);

                while (cpu_public->suspend_cpu)
                        cpu_relax();

                spin_lock(&cpu_public->control_lock);
        }

        cpu_public->cpu_suspended = false;
         ..............
        spin_unlock(&cpu_public->control_lock);
        ............
}

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