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

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Message-ID: <174660886861.406.11820421398467260083.tip-bot2@tip-bot2>
Date: Wed, 07 May 2025 09:07:48 -0000
From: "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org, maz@...nel.org
Subject: [tip: irq/core] genirq: Provide conditional lock guards

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@...utronix.de>
AuthorDate:    Tue, 29 Apr 2025 08:54:49 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.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@...utronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.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)
 {