From: Rafael J. Wysocki <rafael.j.wyso...@intel.com>

Introduce .offline() and .online() callbacks for memory_subsys
that will allow the generic device_offline() and device_online()
to be used with device objects representing memory blocks.  That,
in turn, allows the ACPI subsystem to use device_offline() to put
removable memory blocks offline, if possible, before removing
memory modules holding them.

Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
---
 drivers/base/memory.c          |   84 ++++++++++++++++++++++++++++++-----------
 include/linux/memory_hotplug.h |    2 
 2 files changed, 64 insertions(+), 22 deletions(-)

Index: linux-pm/drivers/base/memory.c
===================================================================
--- linux-pm.orig/drivers/base/memory.c
+++ linux-pm/drivers/base/memory.c
@@ -37,9 +37,14 @@ static inline int base_memory_block_id(i
        return section_nr / sections_per_block;
 }
 
+static int memory_subsys_online(struct device *dev, unsigned int type);
+static int memory_subsys_offline(struct device *dev);
+
 static struct bus_type memory_subsys = {
        .name = MEMORY_CLASS_NAME,
        .dev_name = MEMORY_CLASS_NAME,
+       .online = memory_subsys_online,
+       .offline = memory_subsys_offline,
 };
 
 static BLOCKING_NOTIFIER_HEAD(memory_chain);
@@ -294,16 +299,7 @@ static int __memory_block_change_state(s
        }
 
        mem->state = to_state;
-       switch (mem->state) {
-       case MEM_OFFLINE:
-               kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE);
-               break;
-       case MEM_ONLINE:
-               kobject_uevent(&mem->dev.kobj, KOBJ_ONLINE);
-               break;
-       default:
-               break;
-       }
+
 out:
        return ret;
 }
@@ -321,27 +317,66 @@ static int memory_block_change_state(str
 
        return ret;
 }
+
+static int memory_subsys_online(struct device *dev, unsigned int type)
+{
+       struct memory_block *mem = container_of(dev, struct memory_block, dev);
+
+       if (type < ONLINE_KEEP || type > ONLINE_KERNEL)
+               return -EINVAL;
+
+       return memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE, type);
+}
+
+static int memory_block_online(struct device *dev, unsigned int type)
+{
+       int ret = memory_subsys_online(dev, type);
+
+       if (!ret) {
+               dev->online_type = type;
+               kobject_uevent(&dev->kobj, KOBJ_ONLINE);
+       }
+
+       return ret;
+}
+
+static int memory_subsys_offline(struct device *dev)
+{
+       struct memory_block *mem = container_of(dev, struct memory_block, dev);
+
+       return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE, -1);
+}
+
+static int memory_block_offline(struct device *dev)
+{
+       int ret = memory_subsys_offline(dev);
+
+       if (!ret) {
+               dev->online_type = 0;
+               kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
+       }
+
+       return ret;
+}
+
 static ssize_t
 store_mem_state(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
 {
-       struct memory_block *mem;
        int ret = -EINVAL;
 
-       mem = container_of(dev, struct memory_block, dev);
+       lock_device_hotplug();
 
        if (!strncmp(buf, "online_kernel", min_t(int, count, 13)))
-               ret = memory_block_change_state(mem, MEM_ONLINE,
-                                               MEM_OFFLINE, ONLINE_KERNEL);
+               ret = memory_block_online(dev, ONLINE_KERNEL);
        else if (!strncmp(buf, "online_movable", min_t(int, count, 14)))
-               ret = memory_block_change_state(mem, MEM_ONLINE,
-                                               MEM_OFFLINE, ONLINE_MOVABLE);
+               ret = memory_block_online(dev, ONLINE_MOVABLE);
        else if (!strncmp(buf, "online", min_t(int, count, 6)))
-               ret = memory_block_change_state(mem, MEM_ONLINE,
-                                               MEM_OFFLINE, ONLINE_KEEP);
+               ret = memory_block_online(dev, ONLINE_KEEP);
        else if(!strncmp(buf, "offline", min_t(int, count, 7)))
-               ret = memory_block_change_state(mem, MEM_OFFLINE,
-                                               MEM_ONLINE, -1);
+               ret = memory_block_offline(dev);
+
+       unlock_device_hotplug();
 
        if (ret)
                return ret;
@@ -686,10 +721,17 @@ int offline_memory_block(struct memory_b
 {
        int ret = 0;
 
+       lock_device_hotplug();
        mutex_lock(&mem->state_mutex);
-       if (mem->state != MEM_OFFLINE)
+       if (mem->state != MEM_OFFLINE) {
                ret = __memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE, 
-1);
+               if (!ret) {
+                       mem->dev.online_type = 0;
+                       kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE);
+               }
+       }
        mutex_unlock(&mem->state_mutex);
+       unlock_device_hotplug();
 
        return ret;
 }
Index: linux-pm/include/linux/memory_hotplug.h
===================================================================
--- linux-pm.orig/include/linux/memory_hotplug.h
+++ linux-pm/include/linux/memory_hotplug.h
@@ -28,7 +28,7 @@ enum {
 
 /* Types for control the zone type of onlined memory */
 enum {
-       ONLINE_KEEP,
+       ONLINE_KEEP = 1,
        ONLINE_KERNEL,
        ONLINE_MOVABLE,
 };

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