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Commit d3dcb436 authored by Grant Likely's avatar Grant Likely
Browse files

irqdomain: make irq_linear_revmap() a fast path again 



Over the years, irq_linear_revmap() gained tests and checks to make sure
callers were using it safely, which while important, also make it less
of a fast path. After the irqdomain refactoring done recently, it is now
possible to make irq_linear_revmap() a fast path again. This patch moves
irq_linear_revmap() to the header file and makes it a static inline so
that interrupt controller drivers using a linear mapping can decode the
virq from a hwirq in just a couple of instructions.

Signed-off-by: default avatarGrant Likely <grant.likely@linaro.org>
parent 56a3d5ac

include/linux/irqdomain.h

+16 −3
Original line number Diff line number Diff line
@@ -176,6 +176,22 @@ extern void irq_domain_associate_many(struct irq_domain *domain, 
extern unsigned int irq_create_mapping(struct irq_domain *host,

				       irq_hw_number_t hwirq);

extern void irq_dispose_mapping(unsigned int virq);



/**

 * irq_linear_revmap() - Find a linux irq from a hw irq number.

 * @domain: domain owning this hardware interrupt

 * @hwirq: hardware irq number in that domain space

 *

 * This is a fast path alternative to irq_find_mapping() that can be

 * called directly by irq controller code to save a handful of

 * instructions. It is always safe to call, but won't find irqs mapped

 * using the radix tree.

 */

static inline unsigned int irq_linear_revmap(struct irq_domain *domain,

					     irq_hw_number_t hwirq)

{

	return hwirq < domain->revmap_size ? domain->linear_revmap[hwirq] : 0;

}

extern unsigned int irq_find_mapping(struct irq_domain *host,

				     irq_hw_number_t hwirq);

extern unsigned int irq_create_direct_mapping(struct irq_domain *host);
@@ -189,9 +205,6 @@ static inline int irq_create_identity_mapping(struct irq_domain *host, 
	return irq_create_strict_mappings(host, hwirq, hwirq, 1);

}



extern unsigned int irq_linear_revmap(struct irq_domain *host,

				      irq_hw_number_t hwirq);



extern const struct irq_domain_ops irq_domain_simple_ops;



/* stock xlate functions */

kernel/irq/irqdomain.c

+8 −26
Original line number Diff line number Diff line
@@ -559,34 +559,16 @@ unsigned int irq_find_mapping(struct irq_domain *domain, 
			return hwirq;

	}



	return irq_linear_revmap(domain, hwirq);

}

EXPORT_SYMBOL_GPL(irq_find_mapping);



/**

 * irq_linear_revmap() - Find a linux irq from a hw irq number.

 * @domain: domain owning this hardware interrupt

 * @hwirq: hardware irq number in that domain space

 *

 * This is a fast path that can be called directly by irq controller code to

 * save a handful of instructions.

 */

unsigned int irq_linear_revmap(struct irq_domain *domain,

			       irq_hw_number_t hwirq)

{

	struct irq_data *data;

	/* Check if the hwirq is in the linear revmap. */

	if (hwirq < domain->revmap_size)

		return domain->linear_revmap[hwirq];



	/* Check revmap bounds; complain if exceeded */

	if (hwirq >= domain->revmap_size) {

	rcu_read_lock();

	data = radix_tree_lookup(&domain->revmap_tree, hwirq);

	rcu_read_unlock();

	return data ? data->irq : 0;

}



	return domain->linear_revmap[hwirq];

}

EXPORT_SYMBOL_GPL(irq_linear_revmap);

EXPORT_SYMBOL_GPL(irq_find_mapping);



#ifdef CONFIG_IRQ_DOMAIN_DEBUG

static int virq_debug_show(struct seq_file *m, void *private)