1 files changed, 35 insertions, 72 deletions

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 66a1260b33de..747f401cc312 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -25,6 +25,8 @@ enum mapping_flags {
 	AS_MM_ALL_LOCKS	= __GFP_BITS_SHIFT + 2,	/* under mm_take_all_locks() */
 	AS_UNEVICTABLE	= __GFP_BITS_SHIFT + 3,	/* e.g., ramdisk, SHM_LOCK */
 	AS_EXITING	= __GFP_BITS_SHIFT + 4, /* final truncate in progress */
+	/* writeback related tags are not used */
+	AS_NO_WRITEBACK_TAGS = __GFP_BITS_SHIFT + 5,
 };
 
 static inline void mapping_set_error(struct address_space *mapping, int error)
@@ -64,6 +66,16 @@ static inline int mapping_exiting(struct address_space *mapping)
 	return test_bit(AS_EXITING, &mapping->flags);
 }
 
+static inline void mapping_set_no_writeback_tags(struct address_space *mapping)
+{
+	set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
+}
+
+static inline int mapping_use_writeback_tags(struct address_space *mapping)
+{
+	return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
+}
+
 static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
 {
 	return (__force gfp_t)mapping->flags & __GFP_BITS_MASK;
@@ -396,7 +408,7 @@ static inline loff_t page_offset(struct page *page)
 
 static inline loff_t page_file_offset(struct page *page)
 {
-	return ((loff_t)page_file_index(page)) << PAGE_SHIFT;
+	return ((loff_t)page_index(page)) << PAGE_SHIFT;
 }
 
 extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
@@ -518,109 +530,60 @@ void page_endio(struct page *page, bool is_write, int err);
 extern void add_page_wait_queue(struct page *page, wait_queue_t *waiter);
 
 /*
- * Fault one or two userspace pages into pagetables.
- * Return -EINVAL if more than two pages would be needed.
- * Return non-zero on a fault.
+ * Fault everything in given userspace address range in.
  */
 static inline int fault_in_pages_writeable(char __user *uaddr, int size)
 {
-	int span, ret;
-
-	if (unlikely(size == 0))
-		return 0;
-
-	span = offset_in_page(uaddr) + size;
-	if (span > 2 * PAGE_SIZE)
-		return -EINVAL;
-	/*
-	 * Writing zeroes into userspace here is OK, because we know that if
-	 * the zero gets there, we'll be overwriting it.
-	 */
-	ret = __put_user(0, uaddr);
-	if (ret == 0 && span > PAGE_SIZE)
-		ret = __put_user(0, uaddr + size - 1);
-	return ret;
-}
-
-static inline int fault_in_pages_readable(const char __user *uaddr, int size)
-{
-	volatile char c;
-	int ret;
-
-	if (unlikely(size == 0))
-		return 0;
-
-	ret = __get_user(c, uaddr);
-	if (ret == 0) {
-		const char __user *end = uaddr + size - 1;
-
-		if (((unsigned long)uaddr & PAGE_MASK) !=
-				((unsigned long)end & PAGE_MASK)) {
-			ret = __get_user(c, end);
-			(void)c;
-		}
-	}
-	return ret;
-}
-
-/*
- * Multipage variants of the above prefault helpers, useful if more than
- * PAGE_SIZE of data needs to be prefaulted. These are separate from the above
- * functions (which only handle up to PAGE_SIZE) to avoid clobbering the
- * filemap.c hotpaths.
- */
-static inline int fault_in_multipages_writeable(char __user *uaddr, int size)
-{
-	int ret = 0;
 	char __user *end = uaddr + size - 1;
 
 	if (unlikely(size == 0))
-		return ret;
+		return 0;
 
+	if (unlikely(uaddr > end))
+		return -EFAULT;
 	/*
 	 * Writing zeroes into userspace here is OK, because we know that if
 	 * the zero gets there, we'll be overwriting it.
 	 */
-	while (uaddr <= end) {
-		ret = __put_user(0, uaddr);
-		if (ret != 0)
-			return ret;
+	do {
+		if (unlikely(__put_user(0, uaddr) != 0))
+			return -EFAULT;
 		uaddr += PAGE_SIZE;
-	}
+	} while (uaddr <= end);
 
 	/* Check whether the range spilled into the next page. */
 	if (((unsigned long)uaddr & PAGE_MASK) ==
 			((unsigned long)end & PAGE_MASK))
-		ret = __put_user(0, end);
+		return __put_user(0, end);
 
-	return ret;
+	return 0;
 }
 
-static inline int fault_in_multipages_readable(const char __user *uaddr,
-					       int size)
+static inline int fault_in_pages_readable(const char __user *uaddr, int size)
 {
 	volatile char c;
-	int ret = 0;
 	const char __user *end = uaddr + size - 1;
 
 	if (unlikely(size == 0))
-		return ret;
+		return 0;
+
+	if (unlikely(uaddr > end))
+		return -EFAULT;
 
-	while (uaddr <= end) {
-		ret = __get_user(c, uaddr);
-		if (ret != 0)
-			return ret;
+	do {
+		if (unlikely(__get_user(c, uaddr) != 0))
+			return -EFAULT;
 		uaddr += PAGE_SIZE;
-	}
+	} while (uaddr <= end);
 
 	/* Check whether the range spilled into the next page. */
 	if (((unsigned long)uaddr & PAGE_MASK) ==
 			((unsigned long)end & PAGE_MASK)) {
-		ret = __get_user(c, end);
-		(void)c;
+		return __get_user(c, end);
 	}
 
-	return ret;
+	(void)c;
+	return 0;
 }
 
 int add_to_page_cache_locked(struct page *page, struct address_space *mapping,