[PATCH v3 08/16] iomap: move folio_unlock out of iomap_writeback_folio

[Joanne Koong <joannelkoong@gmail.com>]

Move unlocking the folio out of iomap_writeback_folio into the caller.
This means the end writeback machinery is now run with the folio locked
when no writeback happend, or writeback completed extremely fast.

This prepares for exporting iomap_writeback_folio for use in folio
laundering.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/iomap/buffered-io.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index c6bbee68812e..2973fced2a52 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1656,10 +1656,8 @@ static int iomap_writeback_folio(struct iomap_writepage_ctx *wpc,
 
 	trace_iomap_writepage(inode, pos, folio_size(folio));
 
-	if (!iomap_writeback_handle_eof(folio, inode, &end_pos)) {
-		folio_unlock(folio);
+	if (!iomap_writeback_handle_eof(folio, inode, &end_pos))
 		return 0;
-	}
 	WARN_ON_ONCE(end_pos <= pos);
 
 	if (i_blocks_per_folio(inode, folio) > 1) {
@@ -1713,7 +1711,6 @@ static int iomap_writeback_folio(struct iomap_writepage_ctx *wpc,
 	 * already at this point.  In that case we need to clear the writeback
 	 * bit ourselves right after unlocking the page.
 	 */
-	folio_unlock(folio);
 	if (ifs) {
 		if (atomic_dec_and_test(&ifs->write_bytes_pending))
 			folio_end_writeback(folio);
@@ -1740,8 +1737,10 @@ iomap_writepages(struct iomap_writepage_ctx *wpc)
 			PF_MEMALLOC))
 		return -EIO;
 
-	while ((folio = writeback_iter(mapping, wpc->wbc, folio, &error)))
+	while ((folio = writeback_iter(mapping, wpc->wbc, folio, &error))) {
 		error = iomap_writeback_folio(wpc, folio);
+		folio_unlock(folio);
+	}
 
 	/*
 	 * If @error is non-zero, it means that we have a situation where some
-- 
2.47.1