[PATCH v5 09/10] iomap: advance the iter directly on unshare range

Brian Foster
2025-02-05T13:56:13Z

Modify unshare 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>
---
fs/iomap/buffered-io.c | 23 +++++++++++------------
1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 678c189faa58..f953bf66beb1 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1267,20 +1267,19 @@ EXPORT_SYMBOL_GPL(iomap_write_delalloc_release);
static loff_t iomap_unshare_iter(struct iomap_iter *iter)
{
struct iomap *iomap = &iter->iomap;
- loff_t pos = iter->pos;
- loff_t length = iomap_length(iter);
- loff_t written = 0;
+ u64 bytes = iomap_length(iter);
+ int status;

if (!iomap_want_unshare_iter(iter))
- return length;
+ return iomap_iter_advance(iter, &bytes);

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 (unlikely(status))
return status;
@@ -1298,14 +1297,14 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)

cond_resched();

- pos += bytes;
- written += bytes;
- length -= bytes;
-
balance_dirty_pages_ratelimited(iter->inode->i_mapping);
- } while (length > 0);

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

int
--
2.48.1