Re: [patch 4/5] try2: x86_64: Dont use broadcast shortcut to makeit cpu hotplug safe.

[Andrew Morton]

Ashok Raj <ashok.raj@xxxxxxxxx> wrote:
>
> +static void flat_send_IPI_allbutself(int vector)
> +{
> +	cpumask_t mask;
> +	/*
> +	 * if there are no other CPUs in the system then
> +	 * we get an APIC send error if we try to broadcast.
> +	 * thus we have to avoid sending IPIs in this case.
> +	 */
> +	get_cpu();
> +	mask = cpu_online_map;
> +	cpu_clear(smp_processor_id(), mask);
> +
> +	if (cpus_weight(mask) >= 1)
> +		flat_send_IPI_mask(mask, vector);
> +
> +	put_cpu();
> +}

It would be more idiomatic to use preempt_disable() and preempt_enable() in
place of get_cpu() and put_cpu() here.

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