From: Christoph Hellwig <hch@lst.de>
Date: Tue, 10 Jun 2025 05:49:39 +0000 (+0200)
Subject: mm: tidy up swap_writeout
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2d1844cdbe89d04d4f679a1a01e165fea1741bab;p=thirdparty%2Fkernel%2Flinux.git

mm: tidy up swap_writeout

Use a goto label to consolidate the unlock folio and return pattern and
don't bother with an else after a return / goto.

Link: https://lkml.kernel.org/r/20250610054959.2057526-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/page_io.c b/mm/page_io.c
index f7716b6569fa9..c420b0aa0f22d 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -239,12 +239,11 @@ static void swap_zeromap_folio_clear(struct folio *folio)
  */
 int swap_writeout(struct folio *folio, struct writeback_control *wbc)
 {
-	int ret;
+	int ret = 0;
+
+	if (folio_free_swap(folio))
+		goto out_unlock;
 
-	if (folio_free_swap(folio)) {
-		folio_unlock(folio);
-		return 0;
-	}
 	/*
 	 * Arch code may have to preserve more data than just the page
 	 * contents, e.g. memory tags.
@@ -252,8 +251,7 @@ int swap_writeout(struct folio *folio, struct writeback_control *wbc)
 	ret = arch_prepare_to_swap(folio);
 	if (ret) {
 		folio_mark_dirty(folio);
-		folio_unlock(folio);
-		return ret;
+		goto out_unlock;
 	}
 
 	/*
@@ -264,20 +262,19 @@ int swap_writeout(struct folio *folio, struct writeback_control *wbc)
 	 */
 	if (is_folio_zero_filled(folio)) {
 		swap_zeromap_folio_set(folio);
-		folio_unlock(folio);
-		return 0;
-	} else {
-		/*
-		 * Clear bits this folio occupies in the zeromap to prevent
-		 * zero data being read in from any previous zero writes that
-		 * occupied the same swap entries.
-		 */
-		swap_zeromap_folio_clear(folio);
+		goto out_unlock;
 	}
+
+	/*
+	 * Clear bits this folio occupies in the zeromap to prevent zero data
+	 * being read in from any previous zero writes that occupied the same
+	 * swap entries.
+	 */
+	swap_zeromap_folio_clear(folio);
+
 	if (zswap_store(folio)) {
 		count_mthp_stat(folio_order(folio), MTHP_STAT_ZSWPOUT);
-		folio_unlock(folio);
-		return 0;
+		goto out_unlock;
 	}
 	if (!mem_cgroup_zswap_writeback_enabled(folio_memcg(folio))) {
 		folio_mark_dirty(folio);
@@ -286,6 +283,9 @@ int swap_writeout(struct folio *folio, struct writeback_control *wbc)
 
 	__swap_writepage(folio, wbc);
 	return 0;
+out_unlock:
+	folio_unlock(folio);
+	return ret;
 }
 
 static inline void count_swpout_vm_event(struct folio *folio)