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ACPI / scan: not cache _SUN value in struct acpi_device_pnp 

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 202317a573 (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: 202317a573 (ACPI / scan: Add acpi_device objects for all device nodes in the namespace)
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Yasuaki Ishimatsu 2014-09-03 13:39:13 +09:00 committed by Rafael J. Wysocki
parent 69e273c0b0
commit a383b68d9f
2 changed files with 8 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/acpi/scan.c
View File

@ -667,8 +667,14 @@ 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;
return sprintf(buf, "%lu\n", acpi_dev->pnp.sun);
status = acpi_evaluate_integer(acpi_dev->handle, "_SUN", NULL, &sun);
if (ACPI_FAILURE(status))
return -ENODEV;
return sprintf(buf, "%llu\n", sun);
}
static DEVICE_ATTR(sun, 0444, acpi_device_sun_show, NULL);
@ -690,7 +696,6 @@ 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;
/*
@ -731,14 +736,10 @@ 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")) {

1
include/acpi/acpi_bus.h
View File

@ -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)