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Commit 06f6c339 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

genirq: Implement irq reservation 



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: default avatarThomas Gleixner <tglx@linutronix.de>
parent a98d24b7

include/linux/irq.h

+1 −0
Original line number Diff line number Diff line
@@ -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)

{

kernel/irq/irqdesc.c

+26 −0
Original line number Diff line number Diff line
@@ -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