Subject: [PATCH 1/2] arm64: use num_possible_cpus() instead of NR_CPUS

From: [email-masked] (Sudeep Holla)
Date: Tue, 28 Jan 2014 10:11:13 +0000

On 28/01/14 01:35, Jingoo Han wrote:
> Use num_possible_cpus() instead of direct use of NR_CPUS. Also,
> it fixes the following checkpatch warning.
> 
>   WARNING: usage of NR_CPUS is often wrong - consider using cpu_possible(), num_possible_cpus(), for_each_possible_cpu(), etc
> 
> Signed-off-by: Jingoo Han <[email-masked]>
> ---
>  arch/arm64/kernel/smp.c |   10 +++++-----
>  arch/arm64/mm/context.c |    2 +-
>  2 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index 1b7617a..09ff7d4 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -320,7 +320,7 @@ void __init smp_init_cpus(void)
>  		 * cpu_logical_map was initialized to INVALID_HWID to
>  		 * avoid matching valid MPIDR values.
>  		 */
> -		for (i = 1; (i < cpu) && (i < NR_CPUS); i++) {
> +		for (i = 1; (i < cpu) && (i < num_possible_cpus()); i++) {
>  			if (cpu_logical_map(i) == hwid) {
>  				pr_err("%s: duplicate cpu reg properties in the DT\n",
>  					dn->full_name);
> @@ -352,7 +352,7 @@ void __init smp_init_cpus(void)
>  			continue;
>  		}
>  
> -		if (cpu >= NR_CPUS)
> +		if (cpu >= num_possible_cpus())

Have you tested this patch ? IIUC this will not work as cpu_possible mask is
populated completely and correctly only at the end of this function.

>  			goto next;
>  
>  		if (cpu_read_ops(dn, cpu) != 0)
> @@ -368,9 +368,9 @@ next:
>  	}
>  
>  	/* sanity check */
> -	if (cpu > NR_CPUS)
> +	if (cpu > num_possible_cpus())
>  		pr_warning("no. of cores (%d) greater than configured maximum of %d - clipping\n",
> -			   cpu, NR_CPUS);
> +			   cpu, num_possible_cpus());
>  
>  	if (!bootcpu_valid) {
>  		pr_err("DT missing boot CPU MPIDR, not enabling secondaries\n");
> @@ -381,7 +381,7 @@ next:
>  	 * All the cpus that made it to the cpu_logical_map have been
>  	 * validated so set them as possible cpus.
>  	 */
> -	for (i = 0; i < NR_CPUS; i++)
> +	for (i = 0; i < num_possible_cpus(); i++)
>  		if (cpu_logical_map(i) != INVALID_HWID)
>  			set_cpu_possible(i, true);

This is what I am referring above, where is possible mask set before this.
If it's already populated correctly then we can remove this completely.

Regards,
Sudeep