ntfs3: Convert attr_data_read_resident() to take a folio

Now that all three callers have a folio, pass it in and use
folio_fill_tail() to do the hard work of filling the folio.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Konstantin Komarov <[email protected]>

Author: Matthew Wilcox (Oracle)

fs/ntfs3/attrib.c

@@ -1239,11 +1239,12 @@ int attr_data_get_block(struct ntfs_inode *ni, CLST vcn, CLST clen, CLST *lcn,
 	goto out;
 }
 
-int attr_data_read_resident(struct ntfs_inode *ni, struct page *page)
+int attr_data_read_resident(struct ntfs_inode *ni, struct folio *folio)
 {
 	u64 vbo;
 	struct ATTRIB *attr;
 	u32 data_size;
+	size_t len;
 
 	attr = ni_find_attr(ni, NULL, NULL, ATTR_DATA, NULL, 0, NULL, NULL);
 	if (!attr)
@@ -1252,25 +1253,15 @@ int attr_data_read_resident(struct ntfs_inode *ni, struct page *page)
 	if (attr->non_res)
 		return E_NTFS_NONRESIDENT;
 
-	vbo = page->index << PAGE_SHIFT;
+	vbo = folio->index << PAGE_SHIFT;
 	data_size = le32_to_cpu(attr->res.data_size);
-	if (vbo < data_size) {
-		const char *data = resident_data(attr);
-		char *kaddr = kmap_atomic(page);
-		u32 use = data_size - vbo;
-
-		if (use > PAGE_SIZE)
-			use = PAGE_SIZE;
+	if (vbo > data_size)
+		len = 0;
+	else
+		len = min(data_size - vbo, folio_size(folio));
 
-		memcpy(kaddr, data + vbo, use);
-		memset(kaddr + use, 0, PAGE_SIZE - use);
-		kunmap_atomic(kaddr);
-		flush_dcache_page(page);
-		SetPageUptodate(page);
-	} else if (!PageUptodate(page)) {
-		zero_user_segment(page, 0, PAGE_SIZE);
-		SetPageUptodate(page);
-	}
+	folio_fill_tail(folio, 0, resident_data(attr) + vbo, len);
+	folio_mark_uptodate(folio);
 
 	return 0;
 }

fs/ntfs3/inode.c

@@ -583,7 +583,7 @@ static noinline int ntfs_get_block_vbo(struct inode *inode, u64 vbo,
 			err = 0;
 		} else {
 			ni_lock(ni);
-			err = attr_data_read_resident(ni, &folio->page);
+			err = attr_data_read_resident(ni, folio);
 			ni_unlock(ni);
 
 			if (!err)
@@ -717,7 +717,7 @@ static int ntfs_read_folio(struct file *file, struct folio *folio)
 
 	if (is_resident(ni)) {
 		ni_lock(ni);
-		err = attr_data_read_resident(ni, &folio->page);
+		err = attr_data_read_resident(ni, folio);
 		ni_unlock(ni);
 		if (err != E_NTFS_NONRESIDENT) {
 			folio_unlock(folio);
@@ -923,7 +923,7 @@ int ntfs_write_begin(struct file *file, struct address_space *mapping,
 		}
 
 		ni_lock(ni);
-		err = attr_data_read_resident(ni, &folio->page);
+		err = attr_data_read_resident(ni, folio);
 		ni_unlock(ni);
 
 		if (!err) {

fs/ntfs3/ntfs_fs.h

@@ -434,7 +434,7 @@ int attr_set_size(struct ntfs_inode *ni, enum ATTR_TYPE type,
 		  struct ATTRIB **ret);
 int attr_data_get_block(struct ntfs_inode *ni, CLST vcn, CLST clen, CLST *lcn,
 			CLST *len, bool *new, bool zero);
-int attr_data_read_resident(struct ntfs_inode *ni, struct page *page);
+int attr_data_read_resident(struct ntfs_inode *ni, struct folio *folio);
 int attr_data_write_resident(struct ntfs_inode *ni, struct page *page);
 int attr_load_runs_vcn(struct ntfs_inode *ni, enum ATTR_TYPE type,
 		       const __le16 *name, u8 name_len, struct runs_tree *run,