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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: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Liu Jinsong 2013-02-16 16:59:03 +08:00 committed by Konrad Rzeszutek Wilk
parent 77be36de8b
commit 484400ffbf
1 changed files with 26 additions and 26 deletions
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50
drivers/xen/xen-acpi-memhotplug.c
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@ -158,50 +158,46 @@ acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
return 0; return 0;
} }
static int static int acpi_memory_get_device(acpi_handle handle,
acpi_memory_get_device(acpi_handle handle,
struct acpi_memory_device **mem_device) struct acpi_memory_device **mem_device)
{ {
acpi_status status;
acpi_handle phandle;
struct acpi_device *device = NULL; struct acpi_device *device = NULL;
struct acpi_device *pdevice = NULL; int result = 0;
int result;
if (!acpi_bus_get_device(handle, &device) && device) acpi_scan_lock_acquire();
acpi_bus_get_device(handle, &device);
if (device)
goto end; 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 * Now add the notified device. This creates the acpi_device
* and invokes .add function * and invokes .add function
*/ */
result = acpi_bus_scan(handle); result = acpi_bus_scan(handle);
if (result) { if (result) {
pr_warn(PREFIX "Cannot add acpi bus\n"); pr_warn(PREFIX "ACPI namespace scan failed\n");
return -EINVAL; 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: end:
*mem_device = acpi_driver_data(device); *mem_device = acpi_driver_data(device);
if (!(*mem_device)) { if (!(*mem_device)) {
pr_err(PREFIX "Driver data not found\n"); pr_err(PREFIX "driver data not found\n");
return -ENODEV; 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) 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, ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"\nReceived EJECT REQUEST notification for device\n")); "\nReceived EJECT REQUEST notification for device\n"));
acpi_scan_lock_acquire();
if (acpi_bus_get_device(handle, &device)) { if (acpi_bus_get_device(handle, &device)) {
acpi_scan_lock_release();
pr_err(PREFIX "Device doesn't exist\n"); pr_err(PREFIX "Device doesn't exist\n");
break; break;
} }
mem_device = acpi_driver_data(device); mem_device = acpi_driver_data(device);
if (!mem_device) { if (!mem_device) {
acpi_scan_lock_release();
pr_err(PREFIX "Driver Data is NULL\n"); pr_err(PREFIX "Driver Data is NULL\n");
break; 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_bus_remove if Xen support hotremove in the future
*/ */
acpi_memory_disable_device(mem_device); acpi_memory_disable_device(mem_device);
acpi_scan_lock_release();
break; break;
default: default: