iomap: switch iomap_file_buffered_write to use iomap_iter

Switch iomap_file_buffered_write 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/buffered-io.c

@@ -726,13 +726,14 @@ static size_t iomap_write_end(struct inode *inode, loff_t pos, size_t len,
 	return ret;
 }
 
-static loff_t
-iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
-		struct iomap *iomap, struct iomap *srcmap)
+static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
 {
-	struct iov_iter *i = data;
-	long status = 0;
+	struct iomap *srcmap = iomap_iter_srcmap(iter);
+	struct iomap *iomap = &iter->iomap;
+	loff_t length = iomap_length(iter);
+	loff_t pos = iter->pos;
 	ssize_t written = 0;
+	long status = 0;
 
 	do {
 		struct page *page;
@@ -758,18 +759,18 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 			break;
 		}
 
-		status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap,
-				srcmap);
+		status = iomap_write_begin(iter->inode, pos, bytes, 0, &page,
+					   iomap, srcmap);
 		if (unlikely(status))
 			break;
 
-		if (mapping_writably_mapped(inode->i_mapping))
+		if (mapping_writably_mapped(iter->inode->i_mapping))
 			flush_dcache_page(page);
 
 		copied = copy_page_from_iter_atomic(page, offset, bytes, i);
 
-		status = iomap_write_end(inode, pos, bytes, copied, page, iomap,
-				srcmap);
+		status = iomap_write_end(iter->inode, pos, bytes, copied, page,
+					 iomap, srcmap);
 
 		if (unlikely(copied != status))
 			iov_iter_revert(i, copied - status);
@@ -790,29 +791,29 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 		written += status;
 		length -= status;
 
-		balance_dirty_pages_ratelimited(inode->i_mapping);
+		balance_dirty_pages_ratelimited(iter->inode->i_mapping);
 	} while (iov_iter_count(i) && length);
 
 	return written ? written : status;
 }
 
 ssize_t
-iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter,
+iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i,
 		const struct iomap_ops *ops)
 {
-	struct inode *inode = iocb->ki_filp->f_mapping->host;
-	loff_t pos = iocb->ki_pos, ret = 0, written = 0;
-
-	while (iov_iter_count(iter)) {
-		ret = iomap_apply(inode, pos, iov_iter_count(iter),
-				IOMAP_WRITE, ops, iter, iomap_write_actor);
-		if (ret <= 0)
-			break;
-		pos += ret;
-		written += ret;
-	}
+	struct iomap_iter iter = {
+		.inode		= iocb->ki_filp->f_mapping->host,
+		.pos		= iocb->ki_pos,
+		.len		= iov_iter_count(i),
+		.flags		= IOMAP_WRITE,
+	};
+	int ret;
 
-	return written ? written : ret;
+	while ((ret = iomap_iter(&iter, ops)) > 0)
+		iter.processed = iomap_write_iter(&iter, i);
+	if (iter.pos == iocb->ki_pos)
+		return ret;
+	return iter.pos - iocb->ki_pos;
 }
 EXPORT_SYMBOL_GPL(iomap_file_buffered_write);