ACPI: Use correct IRQ when uninstalling ACPI interrupt handler

commit 49e4b843 upstream.

Currently when the system is trying to uninstall the ACPI interrupt
handler, it uses acpi_gbl_FADT.sci_interrupt as the IRQ number.
However, the IRQ number that the ACPI interrupt handled is installed
for comes from acpi_gsi_to_irq() and that is the number that should
be used for the handler removal.

Fix this problem by using the mapped IRQ returned from acpi_gsi_to_irq()
as appropriate.
Acked-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/acpi/osl.c

@@ -82,6 +82,7 @@ static struct workqueue_struct *kacpid_wq;
 static struct workqueue_struct *kacpi_notify_wq;
 struct workqueue_struct *kacpi_hotplug_wq;
 EXPORT_SYMBOL(kacpi_hotplug_wq);
+unsigned int acpi_sci_irq = INVALID_ACPI_IRQ;
 
 struct acpi_res_list {
 	resource_size_t start;
@@ -566,17 +567,19 @@ acpi_os_install_interrupt_handler(u32 gsi, acpi_osd_handler handler,
 		acpi_irq_handler = NULL;
 		return AE_NOT_ACQUIRED;
 	}
+	acpi_sci_irq = irq;
 
 	return AE_OK;
 }
 
-acpi_status acpi_os_remove_interrupt_handler(u32 irq, acpi_osd_handler handler)
+acpi_status acpi_os_remove_interrupt_handler(u32 gsi, acpi_osd_handler handler)
 {
-	if (irq != acpi_gbl_FADT.sci_interrupt)
+	if (gsi != acpi_gbl_FADT.sci_interrupt || !acpi_sci_irq_valid())
 		return AE_BAD_PARAMETER;
 
-	free_irq(irq, acpi_irq);
+	free_irq(acpi_sci_irq, acpi_irq);
 	acpi_irq_handler = NULL;
+	acpi_sci_irq = INVALID_ACPI_IRQ;
 
 	return AE_OK;
 }

include/linux/acpi.h

@@ -110,6 +110,12 @@ int acpi_unregister_ioapic(acpi_handle handle, u32 gsi_base);
 void acpi_irq_stats_init(void);
 extern u32 acpi_irq_handled;
 extern u32 acpi_irq_not_handled;
+extern unsigned int acpi_sci_irq;
+#define INVALID_ACPI_IRQ	((unsigned)-1)
+static inline bool acpi_sci_irq_valid(void)
+{
+	return acpi_sci_irq != INVALID_ACPI_IRQ;
+}
 
 extern int sbf_port;
 extern unsigned long acpi_realmode_flags;