[RFC v6 01/10] iomap: Add __iomap_put_folio helper

[Andreas Gruenbacher <agruenba@redhat.com>]

Add an __iomap_put_folio() helper to encapsulate unlocking the folio,
calling ->page_done(), and putting the folio.  Use the new helper in
iomap_write_begin() and iomap_write_end().

This effectively doesn't change the way the code works, but prepares for
successive improvements.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/iomap/buffered-io.c | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 356193e44cf0..c045689b6af8 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -575,6 +575,19 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
 	return 0;
 }
 
+static void __iomap_put_folio(struct iomap_iter *iter, loff_t pos, size_t ret,
+		struct folio *folio)
+{
+	const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
+
+	if (folio)
+		folio_unlock(folio);
+	if (page_ops && page_ops->page_done)
+		page_ops->page_done(iter->inode, pos, ret, &folio->page);
+	if (folio)
+		folio_put(folio);
+}
+
 static int iomap_write_begin_inline(const struct iomap_iter *iter,
 		struct folio *folio)
 {
@@ -616,7 +629,8 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
 			fgp, mapping_gfp_mask(iter->inode->i_mapping));
 	if (!folio) {
 		status = (iter->flags & IOMAP_NOWAIT) ? -EAGAIN : -ENOMEM;
-		goto out_no_page;
+		__iomap_put_folio(iter, pos, 0, NULL);
+		return status;
 	}
 
 	/*
@@ -656,13 +670,9 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
 	return 0;
 
 out_unlock:
-	folio_unlock(folio);
-	folio_put(folio);
+	__iomap_put_folio(iter, pos, 0, folio);
 	iomap_write_failed(iter->inode, pos, len);
 
-out_no_page:
-	if (page_ops && page_ops->page_done)
-		page_ops->page_done(iter->inode, pos, 0, NULL);
 	return status;
 }
 
@@ -712,7 +722,6 @@ static size_t iomap_write_end_inline(const struct iomap_iter *iter,
 static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
 		size_t copied, struct folio *folio)
 {
-	const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
 	const struct iomap *srcmap = iomap_iter_srcmap(iter);
 	loff_t old_size = iter->inode->i_size;
 	size_t ret;
@@ -735,14 +744,10 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
 		i_size_write(iter->inode, pos + ret);
 		iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
 	}
-	folio_unlock(folio);
+	__iomap_put_folio(iter, pos, ret, folio);
 
 	if (old_size < pos)
 		pagecache_isize_extended(iter->inode, old_size, pos);
-	if (page_ops && page_ops->page_done)
-		page_ops->page_done(iter->inode, pos, ret, &folio->page);
-	folio_put(folio);
-
 	if (ret < len)
 		iomap_write_failed(iter->inode, pos + ret, len - ret);
 	return ret;
-- 
2.38.1