[PATCH v4 05/11] genirq: Introduce irq_can_move_in_process_context()

[Anup Patel]

The interrupt controller drivers which use GENERIC_PENDING_IRQ
can move interrupts in process context for downstrean devices
which support atomic MSI configuration.

Introduce irq_can_move_in_process_context() which allows interrupt
controller drivers to test whether a particular interrupt can be
moved process context.

Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
---
 include/linux/irq.h    |  2 ++
 kernel/irq/migration.c | 11 +++++++++++
 2 files changed, 13 insertions(+)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 1884fa4ec9b5..5b67a47da144 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -617,6 +617,7 @@ extern int irq_affinity_online_cpu(unsigned int cpu);
 #endif
 
 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_PENDING_IRQ)
+bool irq_can_move_in_process_context(struct irq_data *data);
 void __irq_move_irq(struct irq_data *data);
 static inline void irq_move_irq(struct irq_data *data)
 {
@@ -626,6 +627,7 @@ static inline void irq_move_irq(struct irq_data *data)
 void irq_move_masked_irq(struct irq_data *data);
 void irq_force_complete_move(struct irq_desc *desc);
 #else
+static inline bool irq_can_move_in_process_context(struct irq_data *data) { return true; }
 static inline void irq_move_irq(struct irq_data *data) { }
 static inline void irq_move_masked_irq(struct irq_data *data) { }
 static inline void irq_force_complete_move(struct irq_desc *desc) { }
diff --git a/kernel/irq/migration.c b/kernel/irq/migration.c
index 2920024475a3..428e42d3bc91 100644
--- a/kernel/irq/migration.c
+++ b/kernel/irq/migration.c
@@ -126,3 +126,14 @@ void __irq_move_irq(struct irq_data *idata)
 	if (!masked)
 		idata->chip->irq_unmask(idata);
 }
+
+bool irq_can_move_in_process_context(struct irq_data *data)
+{
+	/*
+	 * Get top level irq_data when CONFIG_IRQ_DOMAIN_HIERARCHY is enabled,
+	 * and it should be optimized away when CONFIG_IRQ_DOMAIN_HIERARCHY is
+	 * disabled. So we avoid an "#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY" here.
+	 */
+	data = irq_desc_get_irq_data(irq_data_to_desc(data));
+	return irq_can_move_pcntxt(data);
+}
-- 
2.43.0