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Message-Id: <20210520163751.27325-15-maz@kernel.org>
Date: Thu, 20 May 2021 17:37:26 +0100
From: Marc Zyngier <maz@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Ley Foon Tan <ley.foon.tan@...el.com>,
Chris Zankel <chris@...kel.net>,
Max Filippov <jcmvbkbc@...il.com>,
Vineet Gupta <vgupta@...opsys.com>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
Robert Jarzmik <robert.jarzmik@...e.fr>,
Russell King <linux@...linux.org.uk>,
Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
Yoshinori Sato <ysato@...rs.sourceforge.jp>,
Rich Felker <dalias@...c.org>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Alex Deucher <alexander.deucher@....com>,
Christian König <christian.koenig@....com>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Rob Clark <robdclark@...il.com>,
Linus Walleij <linus.walleij@...aro.org>,
Lee Jones <lee.jones@...aro.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Rob Herring <robh@...nel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Bartosz Golaszewski <bgolaszewski@...libre.com>,
kernel-team@...roid.com
Subject: [PATCH 14/39] irqdomain: Reimplement irq_linear_revmap() with irq_find_mapping()
irq_linear_revmap() is supposed to be a fast path for domain
lookups, but it only exposes low-level details of the irqdomain
implementation, details which are better kept private.
The *overhead* between the two is only a function call and
a couple of tests, so it is likely that noone can show any
meaningful difference compared to the cost of taking an
interrupt.
Reimplement irq_linear_revmap() with irq_find_mapping()
in order to preserve source code compatibility, and
rename the internal field for a measure.
Signed-off-by: Marc Zyngier <maz@...nel.org>
---
include/linux/irqdomain.h | 22 +++++++++-------------
kernel/irq/irqdomain.c | 6 +++---
2 files changed, 12 insertions(+), 16 deletions(-)
diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 9f884c948739..42b3f7d03a32 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -151,9 +151,9 @@ struct irq_domain_chip_generic;
* Revmap data, used internally by irq_domain
* @revmap_direct_max_irq: The largest hwirq that can be set for controllers that
* support direct mapping
- * @revmap_size: Size of the linear map table @linear_revmap[]
+ * @revmap_size: Size of the linear map table @revmap[]
* @revmap_tree: Radix map tree for hwirqs that don't fit in the linear map
- * @linear_revmap: Linear table of hwirq->virq reverse mappings
+ * @revmap: Linear table of hwirq->virq reverse mappings
*/
struct irq_domain {
struct list_head link;
@@ -177,7 +177,7 @@ struct irq_domain {
unsigned int revmap_size;
struct radix_tree_root revmap_tree;
struct mutex revmap_tree_mutex;
- unsigned int linear_revmap[];
+ unsigned int revmap[];
};
/* Irq domain flags */
@@ -394,24 +394,20 @@ static inline unsigned int irq_create_mapping(struct irq_domain *host,
return irq_create_mapping_affinity(host, hwirq, NULL);
}
-
/**
- * irq_linear_revmap() - Find a linux irq from a hw irq number.
+ * irq_find_mapping() - 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.
*/
+extern unsigned int irq_find_mapping(struct irq_domain *host,
+ irq_hw_number_t hwirq);
+
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;
+ return irq_find_mapping(domain, hwirq);
}
-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);
extern const struct irq_domain_ops irq_domain_simple_ops;
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 6284443b87ec..8bd012253989 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -486,7 +486,7 @@ static void irq_domain_clear_mapping(struct irq_domain *domain,
irq_hw_number_t hwirq)
{
if (hwirq < domain->revmap_size) {
- domain->linear_revmap[hwirq] = 0;
+ domain->revmap[hwirq] = 0;
} else {
mutex_lock(&domain->revmap_tree_mutex);
radix_tree_delete(&domain->revmap_tree, hwirq);
@@ -499,7 +499,7 @@ static void irq_domain_set_mapping(struct irq_domain *domain,
struct irq_data *irq_data)
{
if (hwirq < domain->revmap_size) {
- domain->linear_revmap[hwirq] = irq_data->irq;
+ domain->revmap[hwirq] = irq_data->irq;
} else {
mutex_lock(&domain->revmap_tree_mutex);
radix_tree_insert(&domain->revmap_tree, hwirq, irq_data);
@@ -885,7 +885,7 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
/* Check if the hwirq is in the linear revmap. */
if (hwirq < domain->revmap_size)
- return domain->linear_revmap[hwirq];
+ return domain->revmap[hwirq];
rcu_read_lock();
data = radix_tree_lookup(&domain->revmap_tree, hwirq);
--
2.30.2
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