ACPI / scan: not cache _SUN value in struct acpi_device_pnp

commit a383b68d9fe9864c4d3b86f67ad6488f58136435 upstream.

The _SUN device indentification object is not guaranteed to return
the same value every time it is executed, so we should not cache its
return value, but rather execute it every time as needed.  If it is
cached, an incorrect stale value may be used in some situations.

This issue was exposed by commit 202317a573b2 (ACPI / scan: Add
acpi_device objects for all device nodes in the namespace).  Fix it
by avoiding to cache the return value of _SUN.

Fixes: 202317a573b2 (ACPI / scan: Add acpi_device objects for all device nodes in the namespace)
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 9d60cfd7f2d8edafafee63b9ad0f150cdb8fdb63..551f29127369f51b97c52ca1875cbbf7ee7a5a76 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -665,8 +665,14 @@ static ssize_t
 acpi_device_sun_show(struct device *dev, struct device_attribute *attr,
                     char *buf) {
        struct acpi_device *acpi_dev = to_acpi_device(dev);
+       acpi_status status;
+       unsigned long long sun;
+
+       status = acpi_evaluate_integer(acpi_dev->handle, "_SUN", NULL, &sun);
+       if (ACPI_FAILURE(status))
+               return -ENODEV;
 
-       return sprintf(buf, "%lu\n", acpi_dev->pnp.sun);
+       return sprintf(buf, "%llu\n", sun);
 }
 static DEVICE_ATTR(sun, 0444, acpi_device_sun_show, NULL);
 
@@ -688,7 +694,6 @@ static int acpi_device_setup_files(struct acpi_device *dev)
 {
        struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
        acpi_status status;
-       unsigned long long sun;
        int result = 0;
 
        /*
@@ -729,14 +734,10 @@ static int acpi_device_setup_files(struct acpi_device *dev)
        if (dev->pnp.unique_id)
                result = device_create_file(&dev->dev, &dev_attr_uid);
 
-       status = acpi_evaluate_integer(dev->handle, "_SUN", NULL, &sun);
-       if (ACPI_SUCCESS(status)) {
-               dev->pnp.sun = (unsigned long)sun;
+       if (acpi_has_method(dev->handle, "_SUN")) {
                result = device_create_file(&dev->dev, &dev_attr_sun);
                if (result)
                        goto end;
-       } else {
-               dev->pnp.sun = (unsigned long)-1;
        }
 
        if (acpi_has_method(dev->handle, "_STA")) {

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index b5714580801a54ac2c1c10ae2dcc2a0329042ed7..0826a4407e8e392089fe283b48cbc3d195fcd8bc 100644 (file)
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -246,7 +246,6 @@ struct acpi_device_pnp {
        acpi_device_name device_name;   /* Driver-determined */
        acpi_device_class device_class; /*        "          */
        union acpi_object *str_obj;     /* unicode string for _STR method */
-       unsigned long sun;              /* _SUN */
 };
 
 #define acpi_device_bid(d)     ((d)->pnp.bus_id)