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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>,
	"Darrick J. Wong" <djwong@kernel.org>,
	linux-xfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Jan Kara <jack@suse.cz>,
	Dave Chinner <dchinner@redhat.com>
Subject: [PATCH 11/19] writeback: Use the folio_batch queue iterator
Date: Thu, 25 Jan 2024 09:57:50 +0100
Message-Id: <20240125085758.2393327-12-hch@lst.de>
In-Reply-To: <20240125085758.2393327-1-hch@lst.de>
References: <20240125085758.2393327-1-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: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
---
 mm/page-writeback.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index d6ac414ddce9ca..432bb42d0829d1 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2429,13 +2429,21 @@ static bool folio_prepare_writeback(struct address_space *mapping,
 	return true;
 }
 
-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;
 }
 
 /**
@@ -2475,7 +2483,6 @@ int write_cache_pages(struct address_space *mapping,
 {
 	int error;
 	pgoff_t end;		/* Inclusive */
-	int i = 0;
 
 	if (wbc->range_cyclic) {
 		wbc->index = mapping->writeback_index; /* prev offset */
@@ -2491,18 +2498,12 @@ int write_cache_pages(struct address_space *mapping,
 	wbc->err = 0;
 
 	for (;;) {
-		struct folio *folio;
+		struct folio *folio = writeback_get_folio(mapping, wbc);
 		unsigned long nr;
 
-		if (i == wbc->fbatch.nr) {
-			writeback_get_batch(mapping, wbc);
-			i = 0;
-		}
-		if (wbc->fbatch.nr == 0)
+		if (!folio)
 			break;
 
-		folio = wbc->fbatch.folios[i++];
-
 		folio_lock(folio);
 		if (!folio_prepare_writeback(mapping, wbc, folio)) {
 			folio_unlock(folio);
-- 
2.39.2