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genirq: Implement irq reservation

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Mark a range of interrupts as allocated. In the SPARSE_IRQ=n case we
need this to update the bitmap for the legacy irqs so the enumerator
via irq_get_next_irq() works.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2010-10-12 12:31:46 +02:00
parent a98d24b71b
commit 06f6c3399e
2 changed files with 27 additions and 0 deletions
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1
include/linux/irq.h
View File

@ -400,6 +400,7 @@ static inline struct irq_2_iommu *irq_data_get_iommu(struct irq_data *d)
int irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node);
void irq_free_descs(unsigned int irq, unsigned int cnt);
int irq_reserve_irqs(unsigned int from, unsigned int cnt);
static inline int irq_alloc_desc(int node)
{

26
kernel/irq/irqdesc.c
View File

@ -463,6 +463,32 @@ err:
return ret;
}
/**
* irq_reserve_irqs - mark irqs allocated
* @from: mark from irq number
* @cnt: number of irqs to mark
*
* Returns 0 on success or an appropriate error code
*/
int irq_reserve_irqs(unsigned int from, unsigned int cnt)
{
unsigned long flags;
unsigned int start;
int ret = 0;
if (!cnt || (from + cnt) > nr_irqs)
return -EINVAL;
raw_spin_lock_irqsave(&sparse_irq_lock, flags);
start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0);
if (start == from)
bitmap_set(allocated_irqs, start, cnt);
else
ret = -EEXIST;
raw_spin_unlock_irqrestore(&sparse_irq_lock, flags);
return ret;
}
/**
* irq_get_next_irq - get next allocated irq number
* @offset: where to start the search