[PATCH v2 02/23] vmw_balloon: remove vmballoon_compaction_init()

["David Hildenbrand (Red Hat)" <david@kernel.org>]

Now that there is not a lot of logic left, let's just inline setting up
the migration function and drop all these excessive comments that are
not really required (or true) anymore.

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

Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
---
 drivers/misc/vmw_balloon.c | 30 +++++-------------------------
 1 file changed, 5 insertions(+), 25 deletions(-)

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 2cc34c4968fac..07e60a4b846aa 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1833,27 +1833,10 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
 	up_read(&b->conf_sem);
 	return ret;
 }
-
-/**
- * vmballoon_compaction_init() - initialized compaction for the balloon.
- *
- * @b: pointer to the balloon.
- *
- * If during the initialization a failure occurred, this function does not
- * perform cleanup. The caller must call vmballoon_compaction_deinit() in this
- * case.
- *
- * Return: zero on success or error code on failure.
- */
-static __init void vmballoon_compaction_init(struct vmballoon *b)
-{
-	b->b_dev_info.migratepage = vmballoon_migratepage;
-}
-
 #else /* CONFIG_BALLOON_COMPACTION */
-static inline void vmballoon_compaction_init(struct vmballoon *b)
-{
-}
+int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
+			  struct page *newpage, struct page *page,
+			  enum migrate_mode mode);
 #endif /* CONFIG_BALLOON_COMPACTION */
 
 static int __init vmballoon_init(void)
@@ -1873,12 +1856,9 @@ static int __init vmballoon_init(void)
 	if (error)
 		return error;
 
-	/*
-	 * Initialization of compaction must be done after the call to
-	 * balloon_devinfo_init() .
-	 */
 	balloon_devinfo_init(&balloon.b_dev_info);
-	vmballoon_compaction_init(&balloon);
+	if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
+		balloon.b_dev_info.migratepage = vmballoon_migratepage;
 
 	INIT_LIST_HEAD(&balloon.huge_pages);
 	spin_lock_init(&balloon.comm_lock);
-- 
2.52.0