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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: Grant Likely <grant.likely@linaro.org>
This commit is contained in:
Grant Likely 2013-06-10 12:19:17 +01:00
parent 56a3d5ac77
commit d3dcb436f6
2 changed files with 24 additions and 29 deletions
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19
include/linux/irqdomain.h
View File

@ -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 */

34
kernel/irq/irqdomain.c
View File

@ -559,35 +559,17 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
return hwirq;
}
return irq_linear_revmap(domain, hwirq);
/* Check if the hwirq is in the linear revmap. */
if (hwirq < domain->revmap_size)
return domain->linear_revmap[hwirq];
rcu_read_lock();
data = radix_tree_lookup(&domain->revmap_tree, hwirq);
rcu_read_unlock();
return data ? data->irq : 0;
}
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 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);
#ifdef CONFIG_IRQ_DOMAIN_DEBUG
static int virq_debug_show(struct seq_file *m, void *private)
{