treewide: remove MIGRATEPAGE_SUCCESS

At this point MIGRATEPAGE_SUCCESS is misnamed for all folio users,
and now that we remove MIGRATEPAGE_UNMAP, it's really the only "success"
return value that the code uses and expects.

Let's just get rid of MIGRATEPAGE_SUCCESS completely and just use "0"
for success.

Link: https://lkml.kernel.org/r/20250811143949.1117439-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>			[mm]
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>	[jfs]
Acked-by: David Sterba <dsterba@suse.com>		[btrfs]
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Byungchul Park <byungchul@sk.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Eugenio Pé rez <eperezma@redhat.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Lance Yang <lance.yang@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 1 insertions, 9 deletions

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 302f3e95faea..1f0ac122c3bf 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -12,13 +12,6 @@ typedef void free_folio_t(struct folio *folio, unsigned long private);
 
 struct migration_target_control;
 
-/*
- * Return values from addresss_space_operations.migratepage():
- * - negative errno on page migration failure;
- * - zero on page migration success;
- */
-#define MIGRATEPAGE_SUCCESS		0
-
 /**
  * struct movable_operations - Driver page migration
  * @isolate_page:
@@ -34,8 +27,7 @@ struct migration_target_control;
  * @src page.  The driver should copy the contents of the
  * @src page to the @dst page and set up the fields of @dst page.
  * Both pages are locked.
- * If page migration is successful, the driver should
- * return MIGRATEPAGE_SUCCESS.
+ * If page migration is successful, the driver should return 0.
  * If the driver cannot migrate the page at the moment, it can return
  * -EAGAIN.  The VM interprets this as a temporary migration failure and
  * will retry it later.  Any other error value is a permanent migration