[PATCH 6/8] iomap: Allow a NULL writeback_control argument to iomap_alloc_ioend()

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

When we're doing writethrough, we don't have a writeback_control to
pass in.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/iomap/buffered-io.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index a74da66e64a7..2b89c43aedd7 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1213,9 +1213,13 @@ static struct iomap_ioend *iomap_alloc_ioend(struct inode *inode,
 	bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_VECS, &iomap_ioend_bioset);
 	bio_set_dev(bio, iomap->bdev);
 	bio->bi_iter.bi_sector = sector;
-	bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
+	bio->bi_opf = REQ_OP_WRITE;
 	bio->bi_write_hint = inode->i_write_hint;
-	wbc_init_bio(wbc, bio);
+
+	if (wbc) {
+		bio->bi_opf |= wbc_to_write_flags(wbc);
+		wbc_init_bio(wbc, bio);
+	}
 
 	ioend = container_of(bio, struct iomap_ioend, io_inline_bio);
 	INIT_LIST_HEAD(&ioend->io_list);
-- 
2.30.2