linux-kernel - [PATCH 1/4] acpi,memory-hotplug : add memory offline code to acpi_memory_device

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Date:	Wed, 3 Oct 2012 18:58:43 +0900
From:	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To:	<x86@...nel.org>, <linux-mm@...ck.org>,
	<linux-kernel@...r.kernel.org>, <linux-acpi@...r.kernel.org>
CC:	<rientjes@...gle.com>, <liuj97@...il.com>, <len.brown@...el.com>,
	<cl@...ux.com>, <minchan.kim@...il.com>,
	<akpm@...ux-foundation.org>, <kosaki.motohiro@...fujitsu.com>,
	<wency@...fujitsu.com>
Subject: [PATCH 1/4] acpi,memory-hotplug : add memory offline code to acpi_memory_device_remove()

From: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>

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

In the 1st case, acpi_memory_disable_device() will be called.
In the 2nd case, acpi_memory_device_remove() will be called.
acpi_memory_device_remove() will also be called when we unbind the
memory device from the driver acpi_memhotplug.

acpi_memory_disable_device() has already implemented a code which
offlines memory and releases acpi_memory_info struct . But
acpi_memory_device_remove() has not implemented it yet.

So the patch implements acpi_memory_remove_memory() for offlining
memory and releasing acpi_memory_info struct. And it is used by both
acpi_memory_device_remove() and acpi_memory_disable_device().

Additionally, if the type is ACPI_BUS_REMOVAL_EJECT in
acpi_memory_device_remove() , it means that the user wants to eject
the memory device. In this case, acpi_memory_device_remove() calls
acpi_memory_remove_memory().

CC: David Rientjes <rientjes@...gle.com>
CC: Jiang Liu <liuj97@...il.com>
CC: Len Brown <len.brown@...el.com>
CC: Christoph Lameter <cl@...ux.com>
Cc: Minchan Kim <minchan.kim@...il.com>
CC: Andrew Morton <akpm@...ux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com> 
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
Signed-off-by: Wen Congyang <wency@...fujitsu.com>
---
 drivers/acpi/acpi_memhotplug.c |   44 +++++++++++++++++++++++++++++++----------
 1 file changed, 34 insertions(+), 10 deletions(-)

Index: linux-3.6/drivers/acpi/acpi_memhotplug.c
===================================================================
--- linux-3.6.orig/drivers/acpi/acpi_memhotplug.c	2012-10-03 18:55:33.386378909 +0900
+++ linux-3.6/drivers/acpi/acpi_memhotplug.c	2012-10-03 18:55:58.624380688 +0900
@@ -306,24 +306,37 @@ static int acpi_memory_powerdown_device(
 	return 0;
 }
 
-static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
+static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
 {
 	int result;
 	struct acpi_memory_info *info, *n;
 
+	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
+		if (!info->enabled)
+			return -EBUSY;
+
+		result = remove_memory(info->start_addr, info->length);
+		if (result)
+			return result;
+
+		list_del(&info->list);
+		kfree(info);
+	}
+
+	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
 	 */
-	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
-		if (info->enabled) {
-			result = remove_memory(info->start_addr, info->length);
-			if (result)
-				return result;
-		}
-		kfree(info);
-	}
+	result = acpi_memory_remove_memory(mem_device);
+	if (result)
+		return result;
 
 	/* Power-off and eject the device */
 	result = acpi_memory_powerdown_device(mem_device);
@@ -473,12 +486,23 @@ static int acpi_memory_device_add(struct
 static int acpi_memory_device_remove(struct acpi_device *device, int type)
 {
 	struct acpi_memory_device *mem_device = NULL;
-
+	int result;
 
 	if (!device || !acpi_driver_data(device))
 		return -EINVAL;
 
 	mem_device = acpi_driver_data(device);
+
+	if (type == ACPI_BUS_REMOVAL_EJECT) {
+		/*
+		 * offline and remove memory only when the memory device is
+		 * ejected.
+		 */
+		result = acpi_memory_remove_memory(mem_device);
+		if (result)
+			return result;
+	}
+
 	kfree(mem_device);
 
 	return 0;

--
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