[PATCH 02/10] iomap: advance the iter on direct I/O

[Brian Foster <bfoster@redhat.com>]

Update iomap direct I/O to advance the iter directly rather than via
iter.processed. Since unique subhelpers exist for various mapping
types, advance in the commonly called iomap_dio_iter() function.
Update the switch statement branches to fall out, advance by the
number of bytes processed and return either success or failure.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
 fs/iomap/direct-io.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index b521eb15759e..cb0b0b0f07b3 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -515,22 +515,29 @@ static loff_t iomap_dio_inline_iter(const struct iomap_iter *iomi,
 	return copied;
 }
 
-static loff_t iomap_dio_iter(const struct iomap_iter *iter,
+static int iomap_dio_iter(struct iomap_iter *iter,
 		struct iomap_dio *dio)
 {
+	loff_t len;
+
 	switch (iter->iomap.type) {
 	case IOMAP_HOLE:
 		if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE))
 			return -EIO;
-		return iomap_dio_hole_iter(iter, dio);
+		len = iomap_dio_hole_iter(iter, dio);
+		break;
 	case IOMAP_UNWRITTEN:
 		if (!(dio->flags & IOMAP_DIO_WRITE))
-			return iomap_dio_hole_iter(iter, dio);
-		return iomap_dio_bio_iter(iter, dio);
+			len = iomap_dio_hole_iter(iter, dio);
+		else
+			len = iomap_dio_bio_iter(iter, dio);
+		break;
 	case IOMAP_MAPPED:
-		return iomap_dio_bio_iter(iter, dio);
+		len = iomap_dio_bio_iter(iter, dio);
+		break;
 	case IOMAP_INLINE:
-		return iomap_dio_inline_iter(iter, dio);
+		len = iomap_dio_inline_iter(iter, dio);
+		break;
 	case IOMAP_DELALLOC:
 		/*
 		 * DIO is not serialised against mmap() access at all, and so
@@ -545,6 +552,10 @@ static loff_t iomap_dio_iter(const struct iomap_iter *iter,
 		WARN_ON_ONCE(1);
 		return -EIO;
 	}
+
+	if (len < 0)
+		return len;
+	return iomap_iter_advance(iter, &len);
 }
 
 /*
-- 
2.48.1