1 files changed, 16 insertions, 40 deletions

diff --git a/mm/debug-pagealloc.c b/mm/debug-pagealloc.c
index a1e3324de2b5..7cea557407f4 100644
--- a/mm/debug-pagealloc.c
+++ b/mm/debug-pagealloc.c
@@ -1,7 +1,10 @@
 #include <linux/kernel.h>
+#include <linux/string.h>
 #include <linux/mm.h>
+#include <linux/highmem.h>
 #include <linux/page-debug-flags.h>
 #include <linux/poison.h>
+#include <linux/ratelimit.h>
 
 static inline void set_page_poison(struct page *page)
 {
@@ -18,28 +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)
@@ -59,14 +47,12 @@ static bool single_bit_flip(unsigned char a, unsigned char b)
 
 static void check_poison_mem(unsigned char *mem, size_t bytes)
 {
+	static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10);
 	unsigned char *start;
 	unsigned char *end;
 
-	for (start = mem; start < mem + bytes; start++) {
-		if (*start != PAGE_POISON)
-			break;
-	}
-	if (start == mem + bytes)
+	start = memchr_inv(mem, PAGE_POISON, bytes);
+	if (!start)
 		return;
 
 	for (end = mem + bytes - 1; end > start; end--) {
@@ -74,7 +60,7 @@ static void check_poison_mem(unsigned char *mem, size_t bytes)
 			break;
 	}
 
-	if (!printk_ratelimit())
+	if (!__ratelimit(&ratelimit))
 		return;
 	else if (start == end && single_bit_flip(*start, PAGE_POISON))
 		printk(KERN_ERR "pagealloc: single bit error\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)