[PATCH v6 10/10] iomap: advance the iter directly on zero range

Brian Foster
2025-02-07T14:30:44Z

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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
---
fs/iomap/buffered-io.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index f953bf66beb1..ec227b45f3aa 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1345,17 +1345,16 @@ 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;
+ u64 bytes = iomap_length(iter);
+ int status;

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;
@@ -1376,14 +1375,14 @@ static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
if (WARN_ON_ONCE(!ret))
return -EIO;

- pos += bytes;
- length -= bytes;
- written += bytes;
- } while (length > 0);
+ status = iomap_iter_advance(iter, &bytes);
+ if (status)
+ break;
+ } while (bytes > 0);

if (did_zero)
*did_zero = true;
- return written;
+ return status;
}

int
@@ -1436,11 +1435,14 @@ iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,

if (srcmap->type == IOMAP_HOLE ||
srcmap->type == IOMAP_UNWRITTEN) {
- loff_t proc = iomap_length(&iter);
+ s64 proc;

if (range_dirty) {
range_dirty = false;
proc = iomap_zero_iter_flush_and_stale(&iter);
+ } else {
+ u64 length = iomap_length(&iter);
+ proc = iomap_iter_advance(&iter, &length);
}
iter.processed = proc;
continue;
--
2.48.1