+ mm-tidy-up-swap_writeout.patch added to mm-new branch

+ mm-tidy-up-swap_writeout.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm: tidy up swap_writeout
has been added to the -mm mm-new branch.  Its filename is
     mm-tidy-up-swap_writeout.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-tidy-up-swap_writeout.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

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------------------------------------------------------
From: Christoph Hellwig <hch@lst.de>
Subject: mm: tidy up swap_writeout
Date: Fri, 16 May 2025 09:40:37 +0200

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/20250516074146.178314-4-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>
---

 mm/page_io.c |   36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

--- a/mm/page_io.c~mm-tidy-up-swap_writeout
+++ a/mm/page_io.c
@@ -239,12 +239,11 @@ static void swap_zeromap_folio_clear(str
  */
 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, s
 	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, s
 	 */
 	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, s
 
 	__swap_writepage(folio, wbc);
 	return 0;
+out_unlock:
+	folio_unlock(folio);
+	return ret;
 }
 
 static inline void count_swpout_vm_event(struct folio *folio)
_

Patches currently in -mm which might be from hch@lst.de are

mm-split-out-a-writeout-helper-from-pageout.patch
mm-stop-passing-a-writeback_control-structure-to-shmem_writeout.patch
mm-tidy-up-swap_writeout.patch
mm-stop-passing-a-writeback_control-structure-to-__swap_writepage.patch
mm-stop-passing-a-writeback_control-structure-to-swap_writeout.patch