xen/acpi: xen memory hotplug minor updates
Dan Carpenter found current xen memory hotplug logic
has potential issue: at func acpi_memory_get_device()
*mem_device = acpi_driver_data(device);
while the device may be NULL and then dereference.
At native side, Rafael recently updated acpi_memory_get_device(),
dropping acpi_bus_add, adding lock, and avoiding above issue.
This patch updates xen memory hotplug logic accordingly, removing
redundant logic, adding lock, and avoiding dereference.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/xen/xen-acpi-memhotplug.c b/drivers/xen/xen-acpi-memhotplug.c
index 853b12d..faef5b3 100644
--- a/drivers/xen/xen-acpi-memhotplug.c
+++ b/drivers/xen/xen-acpi-memhotplug.c
@@ -158,50 +158,46 @@
return 0;
}
-static int
-acpi_memory_get_device(acpi_handle handle,
- struct acpi_memory_device **mem_device)
+static int acpi_memory_get_device(acpi_handle handle,
+ struct acpi_memory_device **mem_device)
{
- acpi_status status;
- acpi_handle phandle;
struct acpi_device *device = NULL;
- struct acpi_device *pdevice = NULL;
- int result;
+ int result = 0;
- if (!acpi_bus_get_device(handle, &device) && device)
+ acpi_scan_lock_acquire();
+
+ acpi_bus_get_device(handle, &device);
+ if (device)
goto end;
- status = acpi_get_parent(handle, &phandle);
- if (ACPI_FAILURE(status)) {
- pr_warn(PREFIX "Cannot find acpi parent\n");
- return -EINVAL;
- }
-
- /* Get the parent device */
- result = acpi_bus_get_device(phandle, &pdevice);
- if (result) {
- pr_warn(PREFIX "Cannot get acpi bus device\n");
- return -EINVAL;
- }
-
/*
* Now add the notified device. This creates the acpi_device
* and invokes .add function
*/
result = acpi_bus_scan(handle);
if (result) {
- pr_warn(PREFIX "Cannot add acpi bus\n");
- return -EINVAL;
+ pr_warn(PREFIX "ACPI namespace scan failed\n");
+ result = -EINVAL;
+ goto out;
+ }
+ result = acpi_bus_get_device(handle, &device);
+ if (result) {
+ pr_warn(PREFIX "Missing device object\n");
+ result = -EINVAL;
+ goto out;
}
end:
*mem_device = acpi_driver_data(device);
if (!(*mem_device)) {
- pr_err(PREFIX "Driver data not found\n");
- return -ENODEV;
+ pr_err(PREFIX "driver data not found\n");
+ result = -ENODEV;
+ goto out;
}
- return 0;
+out:
+ acpi_scan_lock_release();
+ return result;
}
static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
@@ -259,12 +255,15 @@
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"\nReceived EJECT REQUEST notification for device\n"));
+ acpi_scan_lock_acquire();
if (acpi_bus_get_device(handle, &device)) {
+ acpi_scan_lock_release();
pr_err(PREFIX "Device doesn't exist\n");
break;
}
mem_device = acpi_driver_data(device);
if (!mem_device) {
+ acpi_scan_lock_release();
pr_err(PREFIX "Driver Data is NULL\n");
break;
}
@@ -274,6 +273,7 @@
* acpi_bus_remove if Xen support hotremove in the future
*/
acpi_memory_disable_device(mem_device);
+ acpi_scan_lock_release();
break;
default: