From 81556b02525181e19ef073a798ba9d48db96f708 Mon Sep 17 00:00:00 2001 From: Zhang Yanfei Date: Tue, 12 Nov 2013 15:07:43 -0800 Subject: [PATCH] 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: Zhang Yanfei Reviewed-by: Wanpeng Li Cc: Wen Congyang Cc: Tang Chen Cc: Toshi Kani Cc: Yasuaki Ishimatsu Cc: Yinghai Lu Cc: Yasunori Goto Cc: Andy Whitcroft Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/sparse.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/mm/sparse.c b/mm/sparse.c index fbb9dbc6aca9..8cc7be0e9590 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -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) -- 2.20.1