[PATCH v2 2/5] genirq: Implement synchronous disable_nmi()

[Mayank Rungta]

Currently, disable_nmi_nosync() is the only interface to disable an NMI
line. Drivers stopping their devices in process context need a synchronous
variant that guarantees any running instance of the NMI handler has
completed on other CPUs before returning.

Implement disable_nmi() by wrapping disable_irq().

Assisted-by: Antigravity:gemini
Signed-off-by: Mayank Rungta <mrungta@xxxxxxxxxx>
---
 include/linux/interrupt.h |  1 +
 kernel/irq/manage.c       | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 3bf969ad8fe0..f13b3ab3829a 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -243,6 +243,7 @@ DEFINE_LOCK_GUARD_1(disable_irq, int,
 		    disable_irq(*_T->lock), enable_irq(*_T->lock))
 
 extern void disable_nmi_nosync(unsigned int irq);
+extern void disable_nmi(unsigned int irq);
 extern void disable_percpu_nmi(unsigned int irq);
 extern void enable_nmi(unsigned int irq);
 extern void enable_percpu_nmi(unsigned int irq, unsigned int type);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 61384925b921..40013aa94481 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -767,6 +767,21 @@ void disable_nmi_nosync(unsigned int irq)
 	disable_irq_nosync(irq);
 }
 
+/**
+ * disable_nmi - disable an nmi and wait for any pending handlers
+ * @irq: Interrupt to disable
+ *
+ * Disable the selected interrupt line. Disables and enables are nested.
+ *
+ * The interrupt to disable must have been requested through request_nmi.
+ * This function ensures existing instances of the NMI handler have
+ * completed before returning.
+ */
+void disable_nmi(unsigned int irq)
+{
+	disable_irq(irq);
+}
+
 void __enable_irq(struct irq_desc *desc)
 {
 	switch (desc->depth) {

-- 
2.55.0.897.gb25b4bd76c-goog