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Commit 484400ff authored by Liu Jinsong's avatar Liu Jinsong Committed by Konrad Rzeszutek Wilk
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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: default avatarLiu Jinsong <jinsong.liu@intel.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 77be36de

drivers/xen/xen-acpi-memhotplug.c

+26 −26
Original line number Diff line number Diff line
@@ -158,31 +158,17 @@ acpi_memory_get_device_resources(struct acpi_memory_device *mem_device) 
	return 0;

}



static int

acpi_memory_get_device(acpi_handle handle,

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)

		goto end;

	acpi_scan_lock_acquire();



	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;

	}

	acpi_bus_get_device(handle, &device);

	if (device)

		goto end;



	/*

	 * Now add the notified device.  This creates the acpi_device
@@ -190,18 +176,28 @@ acpi_memory_get_device(acpi_handle handle, 
	 */

	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 @@ static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data) 
		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 @@ static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data) 
		 * acpi_bus_remove if Xen support hotremove in the future

		 */

		acpi_memory_disable_device(mem_device);

		acpi_scan_lock_release();

		break;



	default: