[PATCH v2 7/7] iomap: advance the iter directly on zero range

[Brian Foster <bfoster@redhat.com>]

Modify zero range to advance the iter directly. Replace the local pos
and length calculations with direct advances and loop based on iter
state instead.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
 fs/iomap/buffered-io.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index ea140d3098ff..83ef6715a4b6 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1341,17 +1341,16 @@ static inline int iomap_zero_iter_flush_and_stale(struct iomap_iter *i)
 
 static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
 {
-	loff_t pos = iter->pos;
-	loff_t length = iomap_length(iter);
-	loff_t written = 0;
+	size_t bytes = iomap_length(iter);
 
 	do {
 		struct folio *folio;
 		int status;
 		size_t offset;
-		size_t bytes = min_t(u64, SIZE_MAX, length);
+		loff_t pos = iter->pos;
 		bool ret;
 
+		bytes = min_t(u64, SIZE_MAX, bytes);
 		status = iomap_write_begin(iter, pos, bytes, &folio);
 		if (status)
 			return status;
@@ -1371,15 +1370,11 @@ static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
 		__iomap_put_folio(iter, pos, bytes, folio);
 		if (WARN_ON_ONCE(!ret))
 			return -EIO;
-
-		pos += bytes;
-		length -= bytes;
-		written += bytes;
-	} while (length > 0);
+	} while ((bytes = iomap_iter_advance(iter, bytes)) > 0);
 
 	if (did_zero)
 		*did_zero = true;
-	return written;
+	return bytes < 0 ? bytes : 0;
 }
 
 int
-- 
2.47.1