[tip: irq/core] genirq: Provide conditional lock guards

tip-bot2 for Thomas Gleixner
2025-05-07T09:07:50Z

The following commit has been merged into the irq/core branch of tip:

Commit-ID: 0f70a49f3fa386d34203efd426a2937592cd26c6
Gitweb: https://git.kernel.org/tip/0f70a49f3fa386d34203efd426a2937592cd26c6
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Tue, 29 Apr 2025 08:54:49 +02:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 07 May 2025 09:08:11 +02:00

genirq: Provide conditional lock guards

The interrupt core code has an ever repeating pattern:

unsigned long flags;
struct irq_desc *desc = irq_get_desc_[bus]lock(irq, &flags, mode);

if (!desc)
return -EINVAL;
....
irq_put_desc_[bus]unlock(desc, flags);

That requires gotos in failure paths and just creates visual clutter.

Provide lock guards, which allow to simplify the code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065420.061659985@linutronix.de

---
kernel/irq/internals.h | 35 +++++++++++++++++++++++++++++------
1 file changed, 29 insertions(+), 6 deletions(-)

diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index b029084..44d3a67 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -141,6 +141,10 @@ extern int irq_setup_affinity(struct irq_desc *desc);
static inline int irq_setup_affinity(struct irq_desc *desc) { return 0; }
#endif

+
+#define for_each_action_of_desc(desc, act) \
+ for (act = desc->action; act; act = act->next)
+
/* Inline functions for support of irq chips on slow busses */
static inline void chip_bus_lock(struct irq_desc *desc)
{
@@ -160,14 +164,33 @@ static inline void chip_bus_sync_unlock(struct irq_desc *desc)
#define IRQ_GET_DESC_CHECK_GLOBAL (_IRQ_DESC_CHECK)
#define IRQ_GET_DESC_CHECK_PERCPU (_IRQ_DESC_CHECK | _IRQ_DESC_PERCPU)

-#define for_each_action_of_desc(desc, act) \
- for (act = desc->action; act; act = act->next)
-
-struct irq_desc *
-__irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
- unsigned int check);
+struct irq_desc *__irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
+ unsigned int check);
void __irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags, bool bus);

+__DEFINE_CLASS_IS_CONDITIONAL(irqdesc_lock, true);
+__DEFINE_UNLOCK_GUARD(irqdesc_lock, struct irq_desc,
+ __irq_put_desc_unlock(_T->lock, _T->flags, _T->bus),
+ unsigned long flags; bool bus);
+
+static inline class_irqdesc_lock_t class_irqdesc_lock_constructor(unsigned int irq, bool bus,
+ unsigned int check)
+{
+ class_irqdesc_lock_t _t = {
+ .bus = bus,
+ .lock = __irq_get_desc_lock(irq, &_t.flags, bus, check),
+ };
+ return _t;
+}
+
+#define scoped_irqdesc_get_and_lock(_irq, _check) \
+ scoped_guard(irqdesc_lock, _irq, false, _check)
+
+#define scoped_irqdesc_get_and_buslock(_irq, _check) \
+ scoped_guard(irqdesc_lock, _irq, true, _check)
+
+#define scoped_irqdesc ((struct irq_desc *)(__guard_ptr(irqdesc_lock)(&scope)))
+
static inline struct irq_desc *
irq_get_desc_buslock(unsigned int irq, unsigned long *flags, unsigned int check)
{