On Thu, 24 Jul 2014 21:00:13 +0800, Hanjun Guo <[email protected]> wrote:
> MADT contains the information for MPIDR which is essential for
> SMP initialization, parse the GIC cpu interface structures to
> get the MPIDR value and map it to cpu_logical_map(), and add
> enabled cpu with valid MPIDR into cpu_possible_map and
> cpu_present_map.
>
> Signed-off-by: Hanjun Guo <[email protected]>
> Signed-off-by: Tomasz Nowicki <[email protected]>
> ---
> + /* If it is the first CPU, no need to check duplicate MPIDRs */
> + if (!enabled_cpus)
> + goto skip_mpidr_check;
> +
> + /*
> + * Duplicate MPIDRs are a recipe for disaster. Scan
> + * all initialized entries and check for
> + * duplicates. If any is found just ignore the CPU.
> + */
> + for_each_present_cpu(cpu) {
> + if (cpu_logical_map(cpu) == mpidr) {
> + pr_err("Firmware bug, duplicate CPU MPIDR: 0x%llx in
> MADT\n",
> + mpidr);
> + return -EINVAL;
> + }
> + }
> +
> +skip_mpidr_check:
> + enabled_cpus++;
So, this hunk is embarrasing. The goto is completely unnecessary and the
whole for_each_present_cpu() block can be inside an
"if (enabled_cpus) { ... }" block. A goto is just nasty.
That said, is the if even necessary? Will for_each_present_cpu() iterate
over anything if it is processing the first cpu? (I don't actually know
the answer here, I did a quick look but not enough to get an
authoritative answer).
g.
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