2013-10-05 16:55:31

by Zhang Yanfei

[permalink] [raw]
Subject: [PATCH v2] mm/sparsemem: Fix a bug in free_map_bootmem when CONFIG_SPARSEMEM_VMEMMAP

From: Zhang Yanfei <[email protected]>

We pass the number of pages which hold page structs of a memory
section to function 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.

Signed-off-by: Zhang Yanfei <[email protected]>
---
v2: Fix a bug introduced in v1 patch. Thanks wanpeng!
---
mm/sparse.c | 20 +++++++++-----------
1 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index 4ac1d7e..fe32b48 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -604,10 +604,10 @@ static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
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);
}
@@ -650,12 +650,15 @@ static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
}

#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;

@@ -759,7 +762,6 @@ 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;
@@ -780,12 +782,8 @@ 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)
--
1.7.1