[PATCH v4 06/19] irqdomain: Drop revmap mutex

Johan Hovold
2023-01-16T13:50:59Z

The global irq_domain_mutex is now held in all paths that update the
revmap structures so there is no longer any need for the revmap mutex.

Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
include/linux/irqdomain.h | 2 --
kernel/irq/irqdomain.c | 13 ++++++-------
2 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 5b2718e1c6de..7fd3939328c2 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -143,7 +143,6 @@ struct irq_domain_chip_generic;
* Revmap data, used internally by the irq domain code:
* @revmap_size: Size of the linear map table @revmap[]
* @revmap_tree: Radix map tree for hwirqs that don't fit in the linear map
- * @revmap_mutex: Lock for the revmap
* @revmap: Linear table of irq_data pointers
*/
struct irq_domain {
@@ -171,7 +170,6 @@ struct irq_domain {
irq_hw_number_t hwirq_max;
unsigned int revmap_size;
struct radix_tree_root revmap_tree;
- struct mutex revmap_mutex;
struct irq_data __rcu *revmap[];
};

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 23f5919e58b7..248e6acfafbe 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -214,7 +214,6 @@ struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, unsigned int s

/* Fill structure */
INIT_RADIX_TREE(&domain->revmap_tree, GFP_KERNEL);
- mutex_init(&domain->revmap_mutex);
domain->ops = ops;
domain->host_data = host_data;
domain->hwirq_max = hwirq_max;
@@ -501,30 +500,30 @@ static bool irq_domain_is_nomap(struct irq_domain *domain)
static void irq_domain_clear_mapping(struct irq_domain *domain,
irq_hw_number_t hwirq)
{
+ lockdep_assert_held(&irq_domain_mutex);
+
if (irq_domain_is_nomap(domain))
return;

- mutex_lock(&domain->revmap_mutex);
if (hwirq < domain->revmap_size)
rcu_assign_pointer(domain->revmap[hwirq], NULL);
else
radix_tree_delete(&domain->revmap_tree, hwirq);
- mutex_unlock(&domain->revmap_mutex);
}

static void irq_domain_set_mapping(struct irq_domain *domain,
irq_hw_number_t hwirq,
struct irq_data *irq_data)
{
+ lockdep_assert_held(&irq_domain_mutex);
+
if (irq_domain_is_nomap(domain))
return;

- mutex_lock(&domain->revmap_mutex);
if (hwirq < domain->revmap_size)
rcu_assign_pointer(domain->revmap[hwirq], irq_data);
else
radix_tree_insert(&domain->revmap_tree, hwirq, irq_data);
- mutex_unlock(&domain->revmap_mutex);
}

static void irq_domain_disassociate(struct irq_domain *domain, unsigned int irq)
@@ -1511,11 +1510,12 @@ static void irq_domain_fix_revmap(struct irq_data *d)
{
void __rcu **slot;

+ lockdep_assert_held(&irq_domain_mutex);
+
if (irq_domain_is_nomap(d->domain))
return;

/* Fix up the revmap. */
- mutex_lock(&d->domain->revmap_mutex);
if (d->hwirq < d->domain->revmap_size) {
/* Not using radix tree */
rcu_assign_pointer(d->domain->revmap[d->hwirq], d);
@@ -1524,7 +1524,6 @@ static void irq_domain_fix_revmap(struct irq_data *d)
if (slot)
radix_tree_replace_slot(&d->domain->revmap_tree, slot, d);
}
- mutex_unlock(&d->domain->revmap_mutex);
}

/**
--
2.38.2