iomap: switch iomap_swapfile_activate to use iomap_iter

Switch iomap_swapfile_activate to use iomap_iter.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

fs/iomap/swapfile.c

@@ -88,13 +88,9 @@ static int iomap_swapfile_fail(struct iomap_swapfile_info *isi, const char *str)
  * swap only cares about contiguous page-aligned physical extents and makes no
  * distinction between written and unwritten extents.
  */
-static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
-		loff_t count, void *data, struct iomap *iomap,
-		struct iomap *srcmap)
+static loff_t iomap_swapfile_iter(const struct iomap_iter *iter,
+		struct iomap *iomap, struct iomap_swapfile_info *isi)
 {
-	struct iomap_swapfile_info *isi = data;
-	int error;
-
 	switch (iomap->type) {
 	case IOMAP_MAPPED:
 	case IOMAP_UNWRITTEN:
@@ -125,12 +121,12 @@ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
 		isi->iomap.length += iomap->length;
 	} else {
 		/* Otherwise, add the retained iomap and store this one. */
-		error = iomap_swapfile_add_extent(isi);
+		int error = iomap_swapfile_add_extent(isi);
 		if (error)
 			return error;
 		memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
 	}
-	return count;
+	return iomap_length(iter);
 }
 
 /*
@@ -141,16 +137,19 @@ int iomap_swapfile_activate(struct swap_info_struct *sis,
 		struct file *swap_file, sector_t *pagespan,
 		const struct iomap_ops *ops)
 {
+	struct inode *inode = swap_file->f_mapping->host;
+	struct iomap_iter iter = {
+		.inode	= inode,
+		.pos	= 0,
+		.len	= ALIGN_DOWN(i_size_read(inode), PAGE_SIZE),
+		.flags	= IOMAP_REPORT,
+	};
 	struct iomap_swapfile_info isi = {
 		.sis = sis,
 		.lowest_ppage = (sector_t)-1ULL,
 		.file = swap_file,
 	};
-	struct address_space *mapping = swap_file->f_mapping;
-	struct inode *inode = mapping->host;
-	loff_t pos = 0;
-	loff_t len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE);
-	loff_t ret;
+	int ret;
 
 	/*
 	 * Persist all file mapping metadata so that we won't have any
@@ -160,15 +159,10 @@ int iomap_swapfile_activate(struct swap_info_struct *sis,
 	if (ret)
 		return ret;
 
-	while (len > 0) {
-		ret = iomap_apply(inode, pos, len, IOMAP_REPORT,
-				ops, &isi, iomap_swapfile_activate_actor);
-		if (ret <= 0)
-			return ret;
-
-		pos += ret;
-		len -= ret;
-	}
+	while ((ret = iomap_iter(&iter, ops)) > 0)
+		iter.processed = iomap_swapfile_iter(&iter, &iter.iomap, &isi);
+	if (ret < 0)
+		return ret;
 
 	if (isi.iomap.length) {
 		ret = iomap_swapfile_add_extent(&isi);