On Tue, 13 Oct 2015, Qais Yousef wrote:
> cpumask is limited to NR_CPUS. introduce ipi_mask which allows us to address
> cpu range that is higher than NR_CPUS which is required for drivers to send
> IPIs for coprocessor that are outside Linux CPU range.
>
> Signed-off-by: Qais Yousef <qais.yousef@xxxxxxxxxx>
> ---
> include/linux/irq.h | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/include/linux/irq.h b/include/linux/irq.h
> index 11bf09288ddb..4b537e4d393b 100644
> --- a/include/linux/irq.h
> +++ b/include/linux/irq.h
> @@ -125,6 +125,21 @@ enum {
> struct msi_desc;
> struct irq_domain;
>
> + /**
> + * struct ipi_mask - IPI mask information
> + * @cpumask: bitmap of cpumasks
> + * @nbits: number of bits in cpumask
> + * @global: whether the mask is SMP IPI ie: subset of cpu_possible_mask or not
> + *
> + * ipi_mask is similar to cpumask, but it provides nbits that's configurable
> + * rather than fixed to NR_CPUS.
> + */
> +struct ipi_mask {
> + unsigned long *cpumask;
> + unsigned int nbits;
> + bool global;
> +};
Can you make that:
struct ipi_mask {
unsigned int nbits;
bool global;
unsigned long cpu_bitmap[];
};
That allows you to allocate the data structure in one go. So the
ipi_mask in irq_data_common becomes a pointer which is only filled in
when ipi_mask is actually used.
Note, I renamed cpumask to cpu_bitmap to avoid confusion with
cpumasks.
We also want a helper function
struct cpumask *irq_data_get_ipi_mask(struct irq_data *data);
so we can use normal cpumask operations for the majority of cases.
Thanks,
tglx
