On Thu, 15 Nov 2012, Wen Congyang wrote:
> The memory device can be removed by 2 ways:
> 1. send eject request by SCI
> 2. echo 1 >/sys/bus/pci/devices/PNP0C80:XX/eject
>
> We handle the 1st case in the module acpi_memhotplug, and handle
> the 2nd case in ACPI eject notification. This 2 events may happen
> at the same time, so we may touch acpi_memory_device.res_list at
> the same time. This patch reimplements memory-hotremove support
> through an ACPI eject notification. Now the memory device is
> offlined and hotremoved only in the function acpi_memory_device_remove()
> which is protected by device_lock().
>
You mean it's protected by device_lock() before calling the remove()
function for eject?
> CC: David Rientjes <rientjes@xxxxxxxxxx>
> CC: Jiang Liu <liuj97@xxxxxxxxx>
> CC: Len Brown <len.brown@xxxxxxxxx>
> CC: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> CC: Paul Mackerras <paulus@xxxxxxxxx>
> CC: Christoph Lameter <cl@xxxxxxxxx>
> Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> CC: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> CC: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
> CC: Rafael J. Wysocki <rjw@xxxxxxx>
> CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
> ---
> drivers/acpi/acpi_memhotplug.c | 87 +++++-------------------------------------
> 1 file changed, 9 insertions(+), 78 deletions(-)
>
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index 2918be1..6e12042 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -272,40 +272,6 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
> return 0;
> }
>
> -static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
> -{
> - acpi_status status;
> - struct acpi_object_list arg_list;
> - union acpi_object arg;
> - unsigned long long current_status;
> -
> -
> - /* Issue the _EJ0 command */
> - arg_list.count = 1;
> - arg_list.pointer = &arg;
> - arg.type = ACPI_TYPE_INTEGER;
> - arg.integer.value = 1;
> - status = acpi_evaluate_object(mem_device->device->handle,
> - "_EJ0", &arg_list, NULL);
> - /* Return on _EJ0 failure */
> - if (ACPI_FAILURE(status)) {
> - ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed"));
> - return -ENODEV;
> - }
> -
> - /* Evalute _STA to check if the device is disabled */
> - status = acpi_evaluate_integer(mem_device->device->handle, "_STA",
> - NULL, ¤t_status);
> - if (ACPI_FAILURE(status))
> - return -ENODEV;
> -
> - /* Check for device status. Device should be disabled */
> - if (current_status & ACPI_STA_DEVICE_ENABLED)
> - return -EINVAL;
> -
> - return 0;
> -}
> -
> static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
> {
> int result;
> @@ -325,34 +291,11 @@ static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
> return 0;
> }
>
> -static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
> -{
> - int result;
> -
> - /*
> - * Ask the VM to offline this memory range.
> - * Note: Assume that this function returns zero on success
> - */
> - result = acpi_memory_remove_memory(mem_device);
> - if (result)
> - return result;
> -
> - /* Power-off and eject the device */
> - result = acpi_memory_powerdown_device(mem_device);
> - if (result) {
> - /* Set the status of the device to invalid */
> - mem_device->state = MEMORY_INVALID_STATE;
> - return result;
> - }
> -
> - mem_device->state = MEMORY_POWER_OFF_STATE;
> - return result;
> -}
> -
> static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
> {
> struct acpi_memory_device *mem_device;
> struct acpi_device *device;
> + struct acpi_eject_event *ej_event = NULL;
> u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
>
> switch (event) {
> @@ -394,31 +337,19 @@ static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
> break;
> }
>
> - /*
> - * Currently disabling memory device from kernel mode
> - * TBD: Can also be disabled from user mode scripts
> - * TBD: Can also be disabled by Callback registration
> - * with generic sysfs driver
> - */
> - if (acpi_memory_disable_device(mem_device)) {
> - printk(KERN_ERR PREFIX "Disable memory device\n");
> - /*
> - * If _EJ0 was called but failed, _OST is not
> - * necessary.
> - */
> - if (mem_device->state == MEMORY_INVALID_STATE)
> - return;
> -
> + ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
> + if (!ej_event) {
> + pr_err(PREFIX "No memory, dropping EJECT\n");
> break;
> }
>
> - /*
> - * TBD: Invoke acpi_bus_remove to cleanup data structures
> - */
> + ej_event->handle = handle;
> + ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
> + acpi_os_hotplug_execute(acpi_bus_hot_remove_device,
> + (void *)ej_event);
>
> - /* _EJ0 succeeded; _OST is not necessary */
> + /* eject is performed asynchronously */
> return;
> -
> default:
> ACPI_DEBUG_PRINT((ACPI_DB_INFO,
> "Unsupported event [0x%x]\n", event));
--
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