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Commit 81556b02 authored by Zhang Yanfei's avatar Zhang Yanfei Committed by Linus Torvalds
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mm/sparsemem: fix a bug in free_map_bootmem when CONFIG_SPARSEMEM_VMEMMAP 



We pass the number of pages which hold page structs of a memory section
to free_map_bootmem().  This is right when !CONFIG_SPARSEMEM_VMEMMAP but
wrong when CONFIG_SPARSEMEM_VMEMMAP.  When CONFIG_SPARSEMEM_VMEMMAP, we
should pass the number of pages of a memory section to free_map_bootmem.

So the fix is removing the nr_pages parameter.  When
CONFIG_SPARSEMEM_VMEMMAP, we directly use the prefined marco
PAGES_PER_SECTION in free_map_bootmem.  When !CONFIG_SPARSEMEM_VMEMMAP,
we calculate page numbers needed to hold the page structs for a memory
section and use the value in free_map_bootmem().

This was found by reading the code.  And I have no machine that support
memory hot-remove to test the bug now.

Signed-off-by: default avatarZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: default avatarWanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 85b35fea

mm/sparse.c

+9 −11
Original line number Diff line number Diff line
@@ -603,10 +603,10 @@ static void __kfree_section_memmap(struct page *memmap) 
	vmemmap_free(start, end);

}

#ifdef CONFIG_MEMORY_HOTREMOVE

static void free_map_bootmem(struct page *memmap, unsigned long nr_pages)

static void free_map_bootmem(struct page *memmap)

{

	unsigned long start = (unsigned long)memmap;

	unsigned long end = (unsigned long)(memmap + nr_pages);

	unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);



	vmemmap_free(start, end);

}
@@ -648,12 +648,15 @@ static void __kfree_section_memmap(struct page *memmap) 
}



#ifdef CONFIG_MEMORY_HOTREMOVE

static void free_map_bootmem(struct page *memmap, unsigned long nr_pages)

static void free_map_bootmem(struct page *memmap)

{

	unsigned long maps_section_nr, removing_section_nr, i;

	unsigned long magic;

	unsigned long magic, nr_pages;

	struct page *page = virt_to_page(memmap);



	nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))

		>> PAGE_SHIFT;



	for (i = 0; i < nr_pages; i++, page++) {

		magic = (unsigned long) page->lru.next;
@@ -756,7 +759,6 @@ static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages) 
static void free_section_usemap(struct page *memmap, unsigned long *usemap)

{

	struct page *usemap_page;

	unsigned long nr_pages;



	if (!usemap)

		return;
@@ -777,12 +779,8 @@ static void free_section_usemap(struct page *memmap, unsigned long *usemap) 
	 * on the section which has pgdat at boot time. Just keep it as is now.

	 */



	if (memmap) {

		nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))

			>> PAGE_SHIFT;



		free_map_bootmem(memmap, nr_pages);

	}

	if (memmap)

		free_map_bootmem(memmap);

}



void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)