From: Akinobu Mita Date: Tue, 1 Nov 2011 00:08:38 +0000 (-0700) Subject: debug-pagealloc: add support for highmem pages X-Git-Tag: firefly_0821_release~3680^2~4252^2~85 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=64212ec569bfdd094f7a23d9b09862209a983559;p=firefly-linux-kernel-4.4.55.git debug-pagealloc: add support for highmem pages This adds support for highmem pages poisoning and verification to the debug-pagealloc feature for no-architecture support. [akpm@linux-foundation.org: remove unneeded preempt_disable/enable] Signed-off-by: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/debug-pagealloc.c b/mm/debug-pagealloc.c index 2618933efdb3..7cea557407f4 100644 --- a/mm/debug-pagealloc.c +++ b/mm/debug-pagealloc.c @@ -1,6 +1,7 @@ #include #include #include +#include #include #include #include @@ -20,28 +21,13 @@ static inline bool page_poison(struct page *page) return test_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags); } -static void poison_highpage(struct page *page) -{ - /* - * Page poisoning for highmem pages is not implemented. - * - * This can be called from interrupt contexts. - * So we need to create a new kmap_atomic slot for this - * application and it will need interrupt protection. - */ -} - static void poison_page(struct page *page) { - void *addr; + void *addr = kmap_atomic(page); - if (PageHighMem(page)) { - poison_highpage(page); - return; - } set_page_poison(page); - addr = page_address(page); memset(addr, PAGE_POISON, PAGE_SIZE); + kunmap_atomic(addr); } static void poison_pages(struct page *page, int n) @@ -86,27 +72,17 @@ static void check_poison_mem(unsigned char *mem, size_t bytes) dump_stack(); } -static void unpoison_highpage(struct page *page) -{ - /* - * See comment in poison_highpage(). - * Highmem pages should not be poisoned for now - */ - BUG_ON(page_poison(page)); -} - static void unpoison_page(struct page *page) { - if (PageHighMem(page)) { - unpoison_highpage(page); + void *addr; + + if (!page_poison(page)) return; - } - if (page_poison(page)) { - void *addr = page_address(page); - check_poison_mem(addr, PAGE_SIZE); - clear_page_poison(page); - } + addr = kmap_atomic(page); + check_poison_mem(addr, PAGE_SIZE); + clear_page_poison(page); + kunmap_atomic(addr); } static void unpoison_pages(struct page *page, int n)