On 2014/1/3 8:05, Yinghai Lu wrote: > For ioapic hot-add support, it would be easy if we have continuous > irq numbers for hot added ioapic controller. > > We can reserve irq range at first, and later allocate desc for those > pre-reserved irqs when they are needed. > > The reasons for not allocating them during reserving: > 1. only several pins of one ioapic are used, allocate for all pins, will > waste memory for not used pins. > 2. allocate later when is needed could make sure irq_desc is allocated > on local node ram, as dev->node is set at that point. > > -v2: update changelog by adding reasons, requested by Konrad. > -v3: according to tglx: > separate core code change with arch code change. > change function name to irq_alloc_reserved_desc. > kill __irq_is_reserved(). > remove not need exports. > according to Sebastian: > spare one comments by put two functions together. > > Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> > Cc: Joerg Roedel <joro@xxxxxxxxxx> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > Cc: Sebastian Andrzej Siewior <sebastian@xxxxxxxxxxxxx> > --- > include/linux/irq.h | 3 +++ > kernel/irq/irqdesc.c | 23 +++++++++++++++++++++++ > 2 files changed, 26 insertions(+) > > diff --git a/include/linux/irq.h b/include/linux/irq.h > index 0229caf..e5f6493 100644 > --- a/include/linux/irq.h > +++ b/include/linux/irq.h > @@ -595,10 +595,13 @@ static inline u32 irq_get_trigger_type(unsigned int irq) > > int __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node, > struct module *owner); > +int __irq_alloc_reserved_desc(int at, int node, struct module *owner); > > /* use macros to avoid needing export.h for THIS_MODULE */ > #define irq_alloc_descs(irq, from, cnt, node) \ > __irq_alloc_descs(irq, from, cnt, node, THIS_MODULE) > +#define irq_alloc_reserved_desc_at(at, node) \ > + __irq_alloc_reserved_desc(at, node, THIS_MODULE) > > #define irq_alloc_desc(node) \ > irq_alloc_descs(-1, 0, 1, node) > diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c > index a151db6..1166545 100644 > --- a/kernel/irq/irqdesc.c > +++ b/kernel/irq/irqdesc.c > @@ -410,6 +410,29 @@ __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node, > EXPORT_SYMBOL_GPL(__irq_alloc_descs); > > /** > + * __irq_alloc_reserved_desc - allocate irq descriptor for irq that is already reserved > + * @irq: Allocate for specific irq number if irq >= 0 Hi Yinghai Should we skip "if irq >= 0" here because irq should have already been reserved? Or should we add range check for irq? Thanks! Gerry > + * @node: Preferred node on which the irq descriptor should be allocated > + * @owner: Owning module (can be NULL) > + * > + * Returns the irq number or error code > + */ > +int __ref __irq_alloc_reserved_desc(int irq, int node, struct module *owner) > +{ > + mutex_lock(&sparse_irq_lock); > + if (!test_bit(irq, allocated_irqs)) { > + mutex_unlock(&sparse_irq_lock); > + return -EINVAL; > + } > + mutex_unlock(&sparse_irq_lock); > + > + if (irq_to_desc(irq)) > + return irq; > + > + return alloc_descs(irq, 1, node, owner); > +} > + > +/** > * irq_reserve_irqs - mark irqs allocated > * @from: mark from irq number > * @cnt: number of irqs to mark > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html