linux-kernel - [PATCH v3 24/25] irq_domain: remove "hint" when allocating irq numbers

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Date:	Fri, 27 Jan 2012 14:36:18 -0700
From:	Grant Likely <grant.likely@...retlab.ca>
To:	linux-kernel@...r.kernel.org,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Milton Miller <miltonm@....com>,
	Rob Herring <rob.herring@...xeda.com>,
	Stephen Rothwell <sfr@...b.auug.org.au>
Cc:	devicetree-discuss@...ts.ozlabs.org,
	linux-arm-kernel@...ts.infradead.org,
	linuxppc-dev@...ts.ozlabs.org,
	Grant Likely <grant.likely@...retlab.ca>
Subject: [PATCH v3 24/25] irq_domain: remove "hint" when allocating irq numbers

The 'hint' used to try and line up irq numbers with hw irq numbers is
rather a hack and not very useful.  Now that /proc/interrupts also outputs
the hwirq number, it is even less useful to keep around the 'hint' heuristic.

This patch removes it.

Signed-off-by: Grant Likely <grant.likely@...retlab.ca>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Milton Miller <miltonm@....com>
---
 kernel/irq/irqdomain.c |   18 ++++--------------
 1 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index bf181ef..5b4fc4d 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -339,7 +339,7 @@ unsigned int irq_create_direct_mapping(struct irq_domain *domain)
 unsigned int irq_create_mapping(struct irq_domain *domain,
 				irq_hw_number_t hwirq)
 {
-	unsigned int virq, hint;
+	unsigned int virq;
 
 	pr_debug("irq: irq_create_mapping(0x%p, 0x%lx)\n", domain, hwirq);
 
@@ -366,10 +366,7 @@ unsigned int irq_create_mapping(struct irq_domain *domain,
 		return irq_domain_legacy_revmap(domain, hwirq);
 
 	/* Allocate a virtual interrupt number */
-	hint = hwirq % irq_virq_count;
-	virq = irq_alloc_desc_from(hint, 0);
-	if (!virq)
-		virq = irq_alloc_desc(0);
+	virq = irq_alloc_desc(0);
 	if (!virq) {
 		pr_debug("irq: -> virq allocation failed\n");
 		return 0;
@@ -490,7 +487,6 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
 			      irq_hw_number_t hwirq)
 {
 	unsigned int i;
-	unsigned int hint = hwirq % irq_virq_count;
 
 	/* Look for default domain if nececssary */
 	if (domain == NULL)
@@ -503,17 +499,11 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
 		return irq_domain_legacy_revmap(domain, hwirq);
 
 	/* Slow path does a linear search of the map */
-	if (hint < NUM_ISA_INTERRUPTS)
-		hint = NUM_ISA_INTERRUPTS;
-	i = hint;
-	do {
+	for (i = 0; i < irq_virq_count; i++)  {
 		struct irq_data *data = irq_get_irq_data(i);
 		if (data && (data->domain == domain) && (data->hwirq == hwirq))
 			return i;
-		i++;
-		if (i >= irq_virq_count)
-			i = NUM_ISA_INTERRUPTS;
-	} while(i != hint);
+	}
 	return 0;
 }
 EXPORT_SYMBOL_GPL(irq_find_mapping);
-- 
1.7.5.4

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