Subject: [PATCH v2 03/23] powerpc/pseries/cmm: remove cmm_balloon_compaction_init()

From: "David Hildenbrand (Red Hat)" <[email-masked]>
Date: Thu, 15 Jan 2026 10:19:53 +0100

Now that there is not a lot of logic left, let's just inline setting up
the migration function.

To avoid #ifdef in the caller we can instead use IS_ENABLED() and make
the compiler happy by only providing the function declaration.

Now that the function is gone, drop the "out_balloon_compaction" label.
Note that before commit 68f2736a8583 ("mm: Convert all PageMovable users
to movable_operations") we actually had to undo something, now not anymore.

Signed-off-by: David Hildenbrand (Red Hat) <[email-masked]>
---
 arch/powerpc/platforms/pseries/cmm.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
index 4cbbe2ee58aba..9a6efbc80d2ad 100644
--- a/arch/powerpc/platforms/pseries/cmm.c
+++ b/arch/powerpc/platforms/pseries/cmm.c
@@ -548,15 +548,9 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info,
 
 	return 0;
 }
-
-static void cmm_balloon_compaction_init(void)
-{
-	b_dev_info.migratepage = cmm_migratepage;
-}
 #else /* CONFIG_BALLOON_COMPACTION */
-static void cmm_balloon_compaction_init(void)
-{
-}
+int cmm_migratepage(struct balloon_dev_info *b_dev_info, struct page *newpage,
+		    struct page *page, enum migrate_mode mode);
 #endif /* CONFIG_BALLOON_COMPACTION */
 
 /**
@@ -573,11 +567,12 @@ static int cmm_init(void)
 		return -EOPNOTSUPP;
 
 	balloon_devinfo_init(&b_dev_info);
-	cmm_balloon_compaction_init();
+	if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
+		b_dev_info.migratepage = cmm_migratepage;
 
 	rc = register_oom_notifier(&cmm_oom_nb);
 	if (rc < 0)
-		goto out_balloon_compaction;
+		return rc;
 
 	if ((rc = register_reboot_notifier(&cmm_reboot_nb)))
 		goto out_oom_notifier;
@@ -606,7 +601,6 @@ static int cmm_init(void)
 	unregister_reboot_notifier(&cmm_reboot_nb);
 out_oom_notifier:
 	unregister_oom_notifier(&cmm_oom_nb);
-out_balloon_compaction:
 	return rc;
 }
 
-- 
2.52.0