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Date: Tue, 13 Oct 2015 15:31:09 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Qais Yousef <qais.yousef@imgtec.com>
cc: linux-kernel@vger.kernel.org, jason@lakedaemon.net, marc.zyngier@arm.com,
        jiang.liu@linux.intel.com, ralf@linux-mips.org,
        linux-mips@linux-mips.org
Subject: Re: [RFC v2 PATCH 06/14] irq: add struct ipi_mapping and its helper
 functions
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References: <1444731382-19313-1-git-send-email-qais.yousef@imgtec.com> <1444731382-19313-7-git-send-email-qais.yousef@imgtec.com>
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On Tue, 13 Oct 2015, Qais Yousef wrote:

> struct ipi_mapping will provide a mechanism for irqdomain/architure
> code to fill out the mapping for the generic code later to implement
> generic IPI reserve and send functions.
> 
> Signed-off-by: Qais Yousef <qais.yousef@imgtec.com>
> ---
>  include/linux/irq.h | 21 +++++++++++++++++++
>  kernel/irq/manage.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 80 insertions(+)
> 
> diff --git a/include/linux/irq.h b/include/linux/irq.h
> index b000b217ea24..c3d0f26c3eff 100644
> --- a/include/linux/irq.h
> +++ b/include/linux/irq.h
> @@ -964,4 +964,25 @@ static inline u32 irq_reg_readl(struct irq_chip_generic *gc,
>  		return readl(gc->reg_base + reg_offset);
>  }
>  
> +#define INVALID_HWIRQ	-1
> +
> +/**
> + * struct ipi_mapping - IPI mapping information object
> + * @nr_hwirqs: number of hwirqs mapped
> + * @nr_cpus: number of cpus the controller can talk to
> + * @cpumap: per cpu hwirq mapping table
> + */
> +struct ipi_mapping {
> +	unsigned int nr_hwirqs;
> +	unsigned int nr_cpus;
> +	unsigned int *cpumap;
> +};

Again, you can avoid seperate allocations and pointer indirections by
s/*cpumap/cpumap[]/
      
> +struct ipi_mapping *irq_alloc_ipi_mapping(unsigned int nr_cpus)
> +{
> +	struct ipi_mapping *map;
> +	int i;
> +
> +	map = kzalloc(sizeof(struct ipi_mapping), GFP_KERNEL);
> +	if (!map)
> +		return NULL;
> +
> +	map->nr_cpus = nr_cpus;
> +
> +	map->cpumap = kmalloc(sizeof(irq_hw_number_t) * nr_cpus, GFP_KERNEL);
> +	if (!map->cpumap) {
> +		kfree(map);
> +		return NULL;
> +	}
> +	for (i = 0; i < nr_cpus; i++)
> +		map->cpumap[i] = INVALID_HWIRQ;

memset please

> +
> +	return map;
> +}
> +
> +void irq_free_ipi_mapping(struct ipi_mapping *map)
> +{
> +	kfree(map->cpumap);
> +	kfree(map);
> +}
> +
> +int irq_map_ipi(struct ipi_mapping *map,
> +		unsigned int cpu, irq_hw_number_t hwirq)
> +{
> +	if (cpu >= map->nr_cpus)
> +		return -EINVAL;
> +
> +	map->cpumap[cpu] = hwirq;
> +	map->nr_hwirqs++;
> +
> +	return 0;
> +}
> +
> +int irq_unmap_ipi(struct ipi_mapping *map,
> +		  unsigned int cpu, irq_hw_number_t *hwirq)
> +{
> +	if (cpu >= map->nr_cpus)
> +		return -EINVAL;
> +
> +	if (map->cpumap[cpu] == INVALID_HWIRQ)
> +		return -EINVAL;
> +
> +	if (hwirq)
> +		*hwirq = map->cpumap[cpu];

Why do we store hwirq in unmap?

All these new functions lack kerneldoc comments.

Thanks,

	tglx