[PATCH] acpi memory hotplug: remove strange add_memory fail message

I wrote a patch to avoid redundant memory hot-add call at boot time.  This
was cause of strange fail message of memory hotplug like "ACPI: add_memory
failed".  Memory is recognized by early boot code with EFI/E820.

But, if DSDT describes memory devices for them, then hot-add code is called
for already recognized memory, and it shows fail messages with -EEXIST.
So, sys admin will misunderstand this message as something wrong by it.

This patch avoids them by preventing redundant hot-add call until
completion of driver initialization.

[akpm@osdl.org: cleanups]
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/acpi/acpi_memhotplug.c

@@ -85,6 +85,8 @@ struct acpi_memory_device {
 	struct list_head res_list;
 };
 
+static int acpi_hotmem_initialized;
+
 static acpi_status
 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
 {
@@ -438,6 +440,15 @@ static int acpi_memory_device_start (struct acpi_device *device)
 	struct acpi_memory_device *mem_device;
 	int result = 0;
 
+	/*
+	 * Early boot code has recognized memory area by EFI/E820.
+	 * If DSDT shows these memory devices on boot, hotplug is not necessary
+	 * for them. So, it just returns until completion of this driver's
+	 * start up.
+	 */
+	if (!acpi_hotmem_initialized)
+		return 0;
+
 	mem_device = acpi_driver_data(device);
 
 	if (!acpi_memory_check_device(mem_device)) {
@@ -537,6 +548,7 @@ static int __init acpi_memory_device_init(void)
 		return -ENODEV;
 	}
 
+	acpi_hotmem_initialized = 1;
 	return 0;
 }