[PATCH 11/14] writeback: Use the folio_batch queue iterator

From: Christoph Hellwig
Date: Mon Feb 12 2024 - 02:18:09 EST


From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>

Instead of keeping our own local iterator variable, use the one just
added to folio_batch.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Acked-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
mm/page-writeback.c | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index a94a77b1805969..62b663debe713b 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2406,13 +2406,21 @@ static pgoff_t wbc_end(struct writeback_control *wbc)
return wbc->range_end >> PAGE_SHIFT;
}

-static void writeback_get_batch(struct address_space *mapping,
+static struct folio *writeback_get_folio(struct address_space *mapping,
struct writeback_control *wbc)
{
- folio_batch_release(&wbc->fbatch);
- cond_resched();
- filemap_get_folios_tag(mapping, &wbc->index, wbc_end(wbc),
- wbc_to_tag(wbc), &wbc->fbatch);
+ struct folio *folio;
+
+ folio = folio_batch_next(&wbc->fbatch);
+ if (!folio) {
+ folio_batch_release(&wbc->fbatch);
+ cond_resched();
+ filemap_get_folios_tag(mapping, &wbc->index, wbc_end(wbc),
+ wbc_to_tag(wbc), &wbc->fbatch);
+ folio = folio_batch_next(&wbc->fbatch);
+ }
+
+ return folio;
}

/**
@@ -2454,7 +2462,6 @@ int write_cache_pages(struct address_space *mapping,
int error;
struct folio *folio;
pgoff_t end; /* Inclusive */
- int i = 0;

if (wbc->range_cyclic) {
wbc->index = mapping->writeback_index; /* prev offset */
@@ -2469,15 +2476,10 @@ int write_cache_pages(struct address_space *mapping,
folio_batch_init(&wbc->fbatch);

for (;;) {
- if (i == wbc->fbatch.nr) {
- writeback_get_batch(mapping, wbc);
- i = 0;
- }
- if (wbc->fbatch.nr == 0)
+ folio = writeback_get_folio(mapping, wbc);
+ if (!folio)
break;

- folio = wbc->fbatch.folios[i++];
-
folio_lock(folio);
if (!folio_prepare_writeback(mapping, wbc, folio)) {
folio_unlock(folio);
--
2.39.2