[RFC v9 PATCH 11/21] memory-hotplug: remove_memory calls __remove_pages

[wency@cn.fujitsu.com]

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

The patch adds __remove_pages() to remove_memory(). Then the range of
phys_start_pfn argument and nr_pages argument in __remove_pagse() may
have different zone. So zone argument is removed from __remove_pages()
and __remove_pages() caluculates zone in each section.

When CONFIG_SPARSEMEM_VMEMMAP is defined, there is no way to remove a memmap.
So __remove_section only calls unregister_memory_section().

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
---
 arch/powerpc/platforms/pseries/hotplug-memory.c |    5 +----
 include/linux/memory_hotplug.h                  |    3 +--
 mm/memory_hotplug.c                             |   17 ++++++++++-------
 3 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index dc0a035..cc14da4 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -76,7 +76,6 @@ unsigned long memory_block_size_bytes(void)
 static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
 {
 	unsigned long start, start_pfn;
-	struct zone *zone;
 	int i, ret;
 	int sections_to_remove;
 
@@ -87,8 +86,6 @@ static int pseries_remove_memblock(unsigned long base, unsigned int memblock_siz
 		return 0;
 	}
 
-	zone = page_zone(pfn_to_page(start_pfn));
-
 	/*
 	 * Remove section mappings and sysfs entries for the
 	 * section of the memory we are removing.
@@ -101,7 +98,7 @@ static int pseries_remove_memblock(unsigned long base, unsigned int memblock_siz
 	sections_to_remove = (memblock_size >> PAGE_SHIFT) / PAGES_PER_SECTION;
 	for (i = 0; i < sections_to_remove; i++) {
 		unsigned long pfn = start_pfn + i * PAGES_PER_SECTION;
-		ret = __remove_pages(zone, start_pfn,  PAGES_PER_SECTION);
+		ret = __remove_pages(start_pfn,  PAGES_PER_SECTION);
 		if (ret)
 			return ret;
 	}
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index fd84ea9..8bf820d 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -90,8 +90,7 @@ extern bool is_pageblock_removable_nolock(struct page *page);
 /* reasonably generic interface to expand the physical pages in a zone  */
 extern int __add_pages(int nid, struct zone *zone, unsigned long start_pfn,
 	unsigned long nr_pages);
-extern int __remove_pages(struct zone *zone, unsigned long start_pfn,
-	unsigned long nr_pages);
+extern int __remove_pages(unsigned long start_pfn, unsigned long nr_pages);
 
 #ifdef CONFIG_NUMA
 extern int memory_add_physaddr_to_nid(u64 start);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 2353887..7fbfc9f 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -275,11 +275,14 @@ static int __meminit __add_section(int nid, struct zone *zone,
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 static int __remove_section(struct zone *zone, struct mem_section *ms)
 {
-	/*
-	 * XXX: Freeing memmap with vmemmap is not implement yet.
-	 *      This should be removed later.
-	 */
-	return -EBUSY;
+	int ret = -EINVAL;
+
+	if (!valid_section(ms))
+		return ret;
+
+	ret = unregister_memory_section(ms);
+
+	return ret;
 }
 #else
 static int __remove_section(struct zone *zone, struct mem_section *ms)
@@ -346,8 +349,7 @@ EXPORT_SYMBOL_GPL(__add_pages);
  * sure that pages are marked reserved and zones are adjust properly by
  * calling offline_pages().
  */
-int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
-		 unsigned long nr_pages)
+int __remove_pages(unsigned long phys_start_pfn, unsigned long nr_pages)
 {
 	unsigned long i, ret = 0;
 	int sections_to_remove;
@@ -363,6 +365,7 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 	sections_to_remove = nr_pages / PAGES_PER_SECTION;
 	for (i = 0; i < sections_to_remove; i++) {
 		unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
+		struct zone *zone = page_zone(pfn_to_page(pfn));
 		ret = __remove_section(zone, __pfn_to_section(pfn));
 		if (ret)
 			break;
-- 
1.7.1