[RFC PATCH 7/12] memory-hotplug : check page type in get_page_bootmem
From: Yasuaki Ishimatsu <hidden>
Date: 2012-06-27 05:53:36
Also in:
linux-acpi, linux-mm, lkml
There is a possibility that get_page_bootmem() is called to the same page many times. So when get_page_bootmem is called to the same page, the function only increments page->_count. CC: Len Brown <redacted> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: Paul Mackerras <redacted> CC: Christoph Lameter <redacted> Cc: Minchan Kim <redacted> CC: Andrew Morton <akpm@linux-foundation.org> CC: KOSAKI Motohiro <redacted> CC: Wen Congyang <redacted> Signed-off-by: Yasuaki Ishimatsu <redacted> Index: linux-3.5-rc4/mm/memory_hotplug.c ===================================================================
--- linux-3.5-rc4.orig/mm/memory_hotplug.c 2012-06-26 13:56:34.371988312 +0900
+++ linux-3.5-rc4/mm/memory_hotplug.c 2012-06-26 14:03:37.564697621 +0900@@ -95,10 +95,17 @@ static void release_memory_resource(stru static void get_page_bootmem(unsigned long info, struct page *page, unsigned long type) { - page->lru.next = (struct list_head *) type; - SetPagePrivate(page); - set_page_private(page, info); - atomic_inc(&page->_count); + unsigned long page_type; + + page_type = (unsigned long) page->lru.next; + if (type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || + type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){ + page->lru.next = (struct list_head *) type; + SetPagePrivate(page); + set_page_private(page, info); + atomic_inc(&page->_count); + } else + atomic_inc(&page->_count); } /* reference to __meminit __free_pages_bootmem is valid