On Sat, Apr 20, 2024 at 01:15:46PM +0800, Dawei Li wrote:
> In general it's preferable to avoid placing cpumasks on the stack, as
> for large values of NR_CPUS these can consume significant amounts of
> stack space and make stack overflows more likely.
>
> Use cpumask_subset() and cpumask_first_and() to avoid the need for a
> temporary cpumask on the stack.
>
> Signed-off-by: Dawei Li <dawei.li@xxxxxxxxxxxx>
> ---
> arch/sparc/kernel/leon_kernel.c | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/arch/sparc/kernel/leon_kernel.c b/arch/sparc/kernel/leon_kernel.c
> index 4c61da491fee..0070655041bb 100644
> --- a/arch/sparc/kernel/leon_kernel.c
> +++ b/arch/sparc/kernel/leon_kernel.c
> @@ -106,13 +106,10 @@ unsigned long leon_get_irqmask(unsigned int irq)
> #ifdef CONFIG_SMP
> static int irq_choose_cpu(const struct cpumask *affinity)
> {
> - cpumask_t mask;
> + unsigned int cpu = cpumask_first_and(affinity, cpu_online_mask);
>
> - cpumask_and(&mask, cpu_online_mask, affinity);
> - if (cpumask_equal(&mask, cpu_online_mask) || cpumask_empty(&mask))
> - return boot_cpu_id;
> - else
> - return cpumask_first(&mask);
> + return cpumask_subset(cpu_online_mask, affinity) || cpu >= nr_cpu_ids ?
> + boot_cpu_id : cpu;
This looks wrong - or if it is correct is is hard to parse.
Drop ?: and use an if so the code is more readable.
Sam
