Re: [PATCH 34/38] irqchip: mips-gic: Make pcpu_masks a per-cpu variable

[Marc Zyngier <marc.zyngier@arm.com>]

On 13/08/17 05:36, Paul Burton wrote:
> Define the pcpu_masks variable using the kernel's standard per-cpu
> variable support, rather than an open-coded array of structs containing
> bitmaps.
> 
> Signed-off-by: Paul Burton <paul.burton@imgtec.com>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: linux-mips@linux-mips.org
> ---
> 
>  drivers/irqchip/irq-mips-gic.c | 17 ++++++++---------
>  1 file changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c
> index feff4bf97577..00153231376a 100644
> --- a/drivers/irqchip/irq-mips-gic.c
> +++ b/drivers/irqchip/irq-mips-gic.c
> @@ -13,6 +13,7 @@
>  #include <linux/irq.h>
>  #include <linux/irqchip.h>
>  #include <linux/of_address.h>
> +#include <linux/percpu.h>
>  #include <linux/sched.h>
>  #include <linux/smp.h>
>  
> @@ -23,6 +24,7 @@
>  #include <dt-bindings/interrupt-controller/mips-gic.h>
>  
>  #define GIC_MAX_INTRS		256
> +#define GIC_MAX_LONGS		BITS_TO_LONGS(GIC_MAX_INTRS)
>  
>  /* Add 2 to convert GIC CPU pin to core interrupt */
>  #define GIC_CPU_PIN_OFFSET	2
> @@ -40,11 +42,8 @@
>  
>  void __iomem *mips_gic_base;
>  
> -struct gic_pcpu_mask {
> -	DECLARE_BITMAP(pcpu_mask, GIC_MAX_INTRS);
> -};
> +DEFINE_PER_CPU_READ_MOSTLY(unsigned long[GIC_MAX_LONGS], pcpu_masks);
>  
> -static struct gic_pcpu_mask pcpu_masks[NR_CPUS];
>  static DEFINE_SPINLOCK(gic_lock);
>  static struct irq_domain *gic_irq_domain;
>  static struct irq_domain *gic_ipi_domain;
> @@ -137,7 +136,7 @@ static void gic_handle_shared_int(bool chained)
>  	DECLARE_BITMAP(intrmask, GIC_MAX_INTRS);
>  
>  	/* Get per-cpu bitmaps */
> -	pcpu_mask = pcpu_masks[smp_processor_id()].pcpu_mask;
> +	pcpu_mask = this_cpu_ptr(pcpu_masks);
>  
>  	if (mips_cm_is64) {
>  		__ioread64_copy(pending, addr_gic_pend(),
> @@ -254,8 +253,8 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *cpumask,
>  
>  	/* Update the pcpu_masks */
>  	for (i = 0; i < min(gic_vpes, NR_CPUS); i++)

Is there any case where gic_vpes is not equal to nr_cpus?

> -		clear_bit(irq, pcpu_masks[i].pcpu_mask);
> -	set_bit(irq, pcpu_masks[cpumask_first(&tmp)].pcpu_mask);
> +		clear_bit(irq, per_cpu_ptr(pcpu_masks, i));
> +	set_bit(irq, per_cpu_ptr(pcpu_masks, cpumask_first(&tmp)));
>  
>  	cpumask_copy(irq_data_get_affinity_mask(d), cpumask);
>  	spin_unlock_irqrestore(&gic_lock, flags);
> @@ -416,8 +415,8 @@ static int gic_shared_irq_domain_map(struct irq_domain *d, unsigned int virq,
>  	write_gic_map_pin(intr, GIC_MAP_PIN_MAP_TO_PIN | gic_cpu_pin);
>  	write_gic_map_vp(intr, BIT(mips_cm_vp_id(vpe)));
>  	for (i = 0; i < min(gic_vpes, NR_CPUS); i++)
> -		clear_bit(intr, pcpu_masks[i].pcpu_mask);
> -	set_bit(intr, pcpu_masks[vpe].pcpu_mask);
> +		clear_bit(intr, per_cpu_ptr(pcpu_masks, i));
> +	set_bit(intr, per_cpu_ptr(pcpu_masks, vpe));
>  	spin_unlock_irqrestore(&gic_lock, flags);
>  
>  	return 0;
> 

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...