ACPI / memhotplug: deal with eject request in hotplug queue

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().

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 9 insertions, 79 deletions

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 736ec047e0fc..6e12042658b8 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, &current_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) {
@@ -394,32 +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;
                 }
 
-                /*
-                 * Invoke acpi_bus_trim() to remove memory device
-                 */
-                acpi_bus_trim(device, 1);
+                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));