[S390] Add support for memory hot-remove.

This patch enables memory hot-remove on s390.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/Kconfig

@@ -317,6 +317,9 @@ config ARCH_ENABLE_MEMORY_HOTPLUG
 	def_bool y
 	depends on SPARSEMEM
 
+config ARCH_ENABLE_MEMORY_HOTREMOVE
+	def_bool y
+
 source "mm/Kconfig"
 
 comment "I/O subsystem configuration"

arch/s390/mm/init.c

@@ -179,7 +179,7 @@ int arch_add_memory(int nid, u64 start, u64 size)
 	int rc;
 
 	pgdat = NODE_DATA(nid);
-	zone = pgdat->node_zones + ZONE_NORMAL;
+	zone = pgdat->node_zones + ZONE_MOVABLE;
 	rc = vmem_add_mapping(start, size);
 	if (rc)
 		return rc;
@@ -189,3 +189,14 @@ int arch_add_memory(int nid, u64 start, u64 size)
 	return rc;
 }
 #endif /* CONFIG_MEMORY_HOTPLUG */
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int remove_memory(u64 start, u64 size)
+{
+	unsigned long start_pfn, end_pfn;
+
+	start_pfn = PFN_DOWN(start);
+	end_pfn = start_pfn + PFN_DOWN(size);
+	return offline_pages(start_pfn, end_pfn, 120 * HZ);
+}
+#endif /* CONFIG_MEMORY_HOTREMOVE */

drivers/s390/char/sclp_cmd.c

@@ -427,13 +427,18 @@ static int sclp_mem_notifier(struct notifier_block *nb,
 			sclp_attach_storage(id);
 	switch (action) {
 	case MEM_ONLINE:
+	case MEM_GOING_OFFLINE:
+	case MEM_CANCEL_OFFLINE:
 		break;
 	case MEM_GOING_ONLINE:
 		rc = sclp_mem_change_state(start, size, 1);
 		break;
 	case MEM_CANCEL_ONLINE:
 		sclp_mem_change_state(start, size, 0);
 		break;
+	case MEM_OFFLINE:
+		sclp_mem_change_state(start, size, 0);
+		break;
 	default:
 		rc = -EINVAL;
 		break;