Re: [PATCH 2/2] parisc: Remove unnecessary NULL check of the kstat_irqs field

[Helge Deller <deller@gmx.de>]

On 7/5/26 23:09, Radu Rendec wrote:
> The kstat_irqs field of struct irq_desc is used to store a per-cpu count
> of interrupt events. It is initialized in init_desc(), along with all
> the other fields in struct irq_desc that need explicit initialization,
> and therefore it's always available (non-NULL) for any valid interrupt
> descriptor.
> 
> On parisc, CONFIG_SPARSE_IRQ is disabled, interrupt descriptors are
> allocated statically in the irq_desc[] array, and kstat_irqs is
> initialized implicitly to NULL. The kstat_irqs field is initialized
> later, for all descriptors, via start_kernel() -> early_irq_init() ->
> init_desc().
> 
> smp_boot_one_cpu() is used only for CPU hotplugging. On a SMP system,
> the boot CPU initializes the interrupt descriptors as described above,
> and smp_boot_one_cpu() is called later, for the secondary CPU(s).
> 
> The previous patch in this series makes a similar change across the
> generic IRQ code in kernel/irq/irqdesc.c, and provides a more detailed
> explanation of why kstat_irqs is guaranteed to be non-NULL.
> 
> Signed-off-by: Radu Rendec <radu@rendec.net>
> ---
>   arch/parisc/kernel/smp.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Acked-by: Helge Deller <deller@gmx.de>