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From: Christoph Hellwig <hch@lst.de>
To: linux-mm@kvack.org
Cc: Matthew Wilcox <willy@infradead.org>,
	Jan Kara <jack@suse.com>,
	David Howells <dhowells@redhat.com>,
	Brian Foster <bfoster@redhat.com>,
	Christian Brauner <brauner@kernel.org>,
	linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Jan Kara <jack@suse.cz>,
	Dave Chinner <dchinner@redhat.com>
Subject: [PATCH 11/14] writeback: Use the folio_batch queue iterator
Date: Thu, 15 Feb 2024 07:36:46 +0100
Message-Id: <20240215063649.2164017-12-hch@lst.de>
In-Reply-To: <20240215063649.2164017-1-hch@lst.de>
References: <20240215063649.2164017-1-hch@lst.de>
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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

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

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
---
 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 358ce3ade9ad1e..3cbe4a7daa357c 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