memory-hotplug: create /sys/firmware/memmap entry for new memory

A memmap is a directory in sysfs which includes 3 text files: start, end
and type.  For example:

start: 	0x100000
end:	0x7e7b1cff
type:	System RAM

Interface firmware_map_add was not called explicitly.  Remove it and add
function firmware_map_add_hotplug as hotplug interface of memmap.

Each memory entry has a memmap in sysfs, When we hot-add new memory, sysfs
does not export memmap entry for it.  We add a call in function add_memory
to function firmware_map_add_hotplug.

Add a new function add_sysfs_fw_map_entry() to create memmap entry, it
will be called when initialize memmap and hot-add memory.

[akpm@linux-foundation.org: un-kernedoc a no longer kerneldoc comment]
Signed-off-by: Shaohui Zheng <shaohui.zheng@intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 43 insertions, 24 deletions

diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c
index 56f9234781fa..20f645743ead 100644
--- a/drivers/firmware/memmap.c
+++ b/drivers/firmware/memmap.c
@@ -122,29 +122,53 @@ static int firmware_map_add_entry(u64 start, u64 end,
         return 0;
 }
 
+/*
+ * Add memmap entry on sysfs
+ */
+static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry)
+{
+        static int map_entries_nr;
+        static struct kset *mmap_kset;
+
+        if (!mmap_kset) {
+                mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);
+                if (!mmap_kset)
+                        return -ENOMEM;
+        }
+
+        entry->kobj.kset = mmap_kset;
+        if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++))
+                kobject_put(&entry->kobj);
+
+        return 0;
+}
+
 /**
- * firmware_map_add() - Adds a firmware mapping entry.
+ * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do
+ * memory hotplug.
  * @start: Start of the memory range.
  * @end:   End of the memory range (inclusive).
  * @type:  Type of the memory range.
  *
- * This function uses kmalloc() for memory
- * allocation. Use firmware_map_add_early() if you want to use the bootmem
- * allocator.
- *
- * That function must be called before late_initcall.
+ * Adds a firmware mapping entry. This function is for memory hotplug, it is
+ * similar to function firmware_map_add_early(). The only difference is that
+ * it will create the syfs entry dynamically.
  *
  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
  **/
-int firmware_map_add(u64 start, u64 end, const char *type)
+int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type)
 {
         struct firmware_map_entry *entry;
 
-        entry = kmalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
+        entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
         if (!entry)
                 return -ENOMEM;
 
-        return firmware_map_add_entry(start, end, type, entry);
+        firmware_map_add_entry(start, end, type, entry);
+        /* create the memmap entry */
+        add_sysfs_fw_map_entry(entry);
+
+        return 0;
 }
 
 /**
@@ -154,7 +178,7 @@ int firmware_map_add(u64 start, u64 end, const char *type)
  * @type:  Type of the memory range.
  *
  * Adds a firmware mapping entry. This function uses the bootmem allocator
- * for memory allocation. Use firmware_map_add() if you want to use kmalloc().
+ * for memory allocation.
  *
  * That function must be called before late_initcall.
  *
@@ -214,19 +238,10 @@ static ssize_t memmap_attr_show(struct kobject *kobj,
  */
 static int __init memmap_init(void)
 {
-        int i = 0;
         struct firmware_map_entry *entry;
-        struct kset *memmap_kset;
-
-        memmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);
-        if (WARN_ON(!memmap_kset))
-                return -ENOMEM;
 
-        list_for_each_entry(entry, &map_entries, list) {
-                entry->kobj.kset = memmap_kset;
-                if (kobject_add(&entry->kobj, NULL, "%d", i++))
-                        kobject_put(&entry->kobj);
-        }
+        list_for_each_entry(entry, &map_entries, list)
+                add_sysfs_fw_map_entry(entry);
 
         return 0;
 }
diff --git a/include/linux/firmware-map.h b/include/linux/firmware-map.h
index 875451f1373a..c6dcc1dfe781 100644
--- a/include/linux/firmware-map.h
+++ b/include/linux/firmware-map.h
@@ -24,17 +24,17 @@
  */
 #ifdef CONFIG_FIRMWARE_MEMMAP
 
-int firmware_map_add(u64 start, u64 end, const char *type);
 int firmware_map_add_early(u64 start, u64 end, const char *type);
+int firmware_map_add_hotplug(u64 start, u64 end, const char *type);
 
 #else /* CONFIG_FIRMWARE_MEMMAP */
 
-static inline int firmware_map_add(u64 start, u64 end, const char *type)
+static inline int firmware_map_add_early(u64 start, u64 end, const char *type)
 {
         return 0;
 }
 
-static inline int firmware_map_add_early(u64 start, u64 end, const char *type)
+static inline int firmware_map_add_hotplug(u64 start, u64 end, const char *type)
 {
         return 0;
 }
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 030ce8a5bb0e..78e34e63c7b8 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -28,6 +28,7 @@
 #include <linux/pfn.h>
 #include <linux/suspend.h>
 #include <linux/mm_inline.h>
+#include <linux/firmware-map.h>
 
 #include <asm/tlbflush.h>
 
@@ -523,6 +524,9 @@ int __ref add_memory(int nid, u64 start, u64 size)
                 BUG_ON(ret);
         }
 
+        /* create new memmap entry */
+        firmware_map_add_hotplug(start, start + size, "System RAM");
+
         goto out;
 
 error: