[PATCH v2 7/7] genirq/chip: Constify the 'chip' field in irq_data

Commit 393e1280f765 ("genirq: Allow irq_chip registration functions to take
a const irq_chip") and ef6e5d61eb7a ("genirq: Allow
irq_set_chip_handler_name_locked() to take a const irq_chip") have
introduced some ugly casting to store some const parameters into non-const
struct members. [1] [2]

Correctly constify this 'chip' field in struct irq_data, update
corresponding asseccors and remove the now useless cast in
irq_set_chip_handler_name_locked() and irq_set_chip().

[1]: https://elixir.bootlin.com/linux/v7.1-rc5/source/kernel/irq/chip.c#L48
[2]: https://elixir.bootlin.com/linux/v7.1-rc5/source/include/linux/irqdesc.h#L250

Signed-off-by: Christophe JAILLET <[email protected]>
---
Compile-tested only, on x86

Changes in v2:
   - New patch

v1: none
---
 include/linux/irq.h     | 6 +++---
 include/linux/irqdesc.h | 4 ++--
 kernel/irq/chip.c       | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index efa514ee562f..cde56cb98db3 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -183,7 +183,7 @@ struct irq_data {
 	unsigned int		irq;
 	irq_hw_number_t		hwirq;
 	struct irq_common_data	*common;
-	struct irq_chip		*chip;
+	const struct irq_chip	*chip;
 	struct irq_domain	*domain;
 #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
 	struct irq_data		*parent_data;
@@ -817,13 +817,13 @@ extern int irq_set_msi_desc_off(unsigned int irq_base, unsigned int irq_offset,
 				struct msi_desc *entry);
 extern struct irq_data *irq_get_irq_data(unsigned int irq);
 
-static inline struct irq_chip *irq_get_chip(unsigned int irq)
+static inline const struct irq_chip *irq_get_chip(unsigned int irq)
 {
 	struct irq_data *d = irq_get_irq_data(irq);
 	return d ? d->chip : NULL;
 }
 
-static inline struct irq_chip *irq_data_get_irq_chip(struct irq_data *d)
+static inline const struct irq_chip *irq_data_get_irq_chip(struct irq_data *d)
 {
 	return d->chip;
 }
diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index dae9a9b93665..53dbed301375 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -162,7 +162,7 @@ static inline struct irq_data *irq_desc_get_irq_data(struct irq_desc *desc)
 	return &desc->irq_data;
 }
 
-static inline struct irq_chip *irq_desc_get_chip(struct irq_desc *desc)
+static inline const struct irq_chip *irq_desc_get_chip(struct irq_desc *desc)
 {
 	return desc->irq_data.chip;
 }
@@ -247,7 +247,7 @@ irq_set_chip_handler_name_locked(struct irq_data *data,
 
 	desc->handle_irq = handler;
 	desc->name = name;
-	data->chip = (struct irq_chip *)chip;
+	data->chip = chip;
 }
 
 bool irq_check_status_bit(unsigned int irq, unsigned int bitmask);
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 957e4264bf46..b97881ac7775 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -45,7 +45,7 @@ int irq_set_chip(unsigned int irq, const struct irq_chip *chip)
 	int ret = -EINVAL;
 
 	scoped_irqdesc_get_and_lock(irq, 0) {
-		scoped_irqdesc->irq_data.chip = (struct irq_chip *)(chip ?: &no_irq_chip);
+		scoped_irqdesc->irq_data.chip = chip ?: &no_irq_chip;
 		ret = 0;
 	}
 	/* For !CONFIG_SPARSE_IRQ make the irq show up in allocated_irqs. */
-- 
2.54.0