+ mm-shmem-swap-simplify-swapin-path-and-result-handling.patch added to mm-unstable branch

+ mm-shmem-swap-simplify-swapin-path-and-result-handling.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/shmem, swap: simplify swapin path and result handling
has been added to the -mm mm-unstable branch.  Its filename is
     mm-shmem-swap-simplify-swapin-path-and-result-handling.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-shmem-swap-simplify-swapin-path-and-result-handling.patch

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

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------------------------------------------------------
From: Kairui Song <kasong@tencent.com>
Subject: mm/shmem, swap: simplify swapin path and result handling
Date: Sat, 5 Jul 2025 02:17:46 +0800

Slightly tidy up the different handling of swap in and error handling for
SWP_SYNCHRONOUS_IO and non-SWP_SYNCHRONOUS_IO devices.  Now swapin will
always use either shmem_swapin_direct or shmem_swapin_cluster, then check
the result.

Simplify the control flow and avoid a redundant goto label.

Link: https://lkml.kernel.org/r/20250704181748.63181-8-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/shmem.c |   31 +++++++++++++------------------
 1 file changed, 13 insertions(+), 18 deletions(-)

--- a/mm/shmem.c~mm-shmem-swap-simplify-swapin-path-and-result-handling
+++ a/mm/shmem.c
@@ -2327,33 +2327,28 @@ static int shmem_swapin_folio(struct ino
 			count_vm_event(PGMAJFAULT);
 			count_memcg_event_mm(fault_mm, PGMAJFAULT);
 		}
-		/* Skip swapcache for synchronous device. */
 		if (data_race(si->flags & SWP_SYNCHRONOUS_IO)) {
+			/* Direct mTHP swapin skipping swap cache & readhaed */
 			folio = shmem_swapin_direct(inode, vma, index, swap,
 						    index_entry, order, gfp);
-			if (!IS_ERR(folio)) {
+			if (IS_ERR(folio)) {
+				error = PTR_ERR(folio);
+				folio = NULL;
+				goto failed;
+			} else {
 				if (folio_test_large(folio))
 					swap = index_entry;
 				skip_swapcache = true;
-				goto alloced;
 			}
-
-			/*
-			 * Direct swapin handled order 0 fallback already,
-			 * if it failed, abort.
-			 */
-			error = PTR_ERR(folio);
-			folio = NULL;
-			goto failed;
-		}
-		/* Cached swapin with readahead, only supports order 0 */
-		folio = shmem_swapin_cluster(swap, gfp, info, index);
-		if (!folio) {
-			error = -ENOMEM;
-			goto failed;
+		} else {
+			/* Cached swapin with readhaed, only supports order 0 */
+			folio = shmem_swapin_cluster(swap, gfp, info, index);
+			if (!folio) {
+				error = -ENOMEM;
+				goto failed;
+			}
 		}
 	}
-alloced:
 	if (order > folio_order(folio)) {
 		/*
 		 * Swapin may get smaller folios due to various reasons:
_

Patches currently in -mm which might be from kasong@tencent.com are

mm-list_lru-refactor-the-locking-code.patch
mm-shmem-swap-improve-cached-mthp-handling-and-fix-potential-hung.patch
mm-shmem-swap-avoid-redundant-xarray-lookup-during-swapin.patch
mm-shmem-swap-tidy-up-thp-swapin-checks.patch
mm-shmem-swap-tidy-up-swap-entry-splitting.patch
mm-shmem-swap-avoid-false-positive-swap-cache-lookup.patch
mm-shmem-swap-never-use-swap-cache-and-readahead-for-swp_synchronous_io.patch
mm-shmem-swap-simplify-swapin-path-and-result-handling.patch
mm-shmem-swap-simplify-swap-entry-and-index-calculation-of-large-swapin.patch
mm-shmem-swap-fix-major-fault-counting.patch