+ btree-fix-merge-logic-to-use-btree_last-return-value.patch added to mm-nonmm-unstable branch

+ btree-fix-merge-logic-to-use-btree_last-return-value.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: btree: fix merge logic to use btree_last() return value
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     btree-fix-merge-logic-to-use-btree_last-return-value.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/btree-fix-merge-logic-to-use-btree_last-return-value.patch

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

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------------------------------------------------------
From: "Guan-Chun.Wu" <409411716@gms.tku.edu.tw>
Subject: btree: fix merge logic to use btree_last() return value
Date: Fri, 22 Aug 2025 16:58:51 +0800

Previously btree_merge() called btree_last() only to test existence, then
performed an extra btree_lookup() to fetch the value.  This patch changes
it to directly use the value returned by btree_last(), avoiding redundant
lookups and simplifying the merge loop.

Link: https://lkml.kernel.org/r/20250822085851.566303-1-409411716@gms.tku.edu.tw
Signed-off-by: Guan-Chun.Wu <409411716@gms.tku.edu.tw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/btree.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/lib/btree.c~btree-fix-merge-logic-to-use-btree_last-return-value
+++ a/lib/btree.c
@@ -653,9 +653,9 @@ int btree_merge(struct btree_head *targe
 	 * walks to remove a single object from the victim.
 	 */
 	for (;;) {
-		if (!btree_last(victim, geo, key))
+		val = btree_last(victim, geo, key);
+		if (!val)
 			break;
-		val = btree_lookup(victim, geo, key);
 		err = btree_insert(target, geo, key, val, gfp);
 		if (err)
 			return err;
_

Patches currently in -mm which might be from 409411716@gms.tku.edu.tw are

btree-fix-merge-logic-to-use-btree_last-return-value.patch