mm: remove PageMovable export

The only in-kernel users that need PageMovable() to be exported are z3fold
and zsmalloc and they are only using it for dubious debugging
functionality.  So remove those usages and the export so that no driver
code accidentally thinks that they are allowed to use this symbol.

Link: https://lkml.kernel.org/r/20230106135900.3763622-1-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/compaction.c

@@ -122,7 +122,6 @@ bool PageMovable(struct page *page)
 
 	return false;
 }
-EXPORT_SYMBOL(PageMovable);
 
 void __SetPageMovable(struct page *page, const struct movable_operations *mops)
 {

mm/z3fold.c

@@ -1450,7 +1450,6 @@ static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode)
 	struct z3fold_header *zhdr;
 	struct z3fold_pool *pool;
 
-	VM_BUG_ON_PAGE(!PageMovable(page), page);
 	VM_BUG_ON_PAGE(PageIsolated(page), page);
 
 	if (test_bit(PAGE_HEADLESS, &page->private))
@@ -1490,7 +1489,6 @@ static int z3fold_page_migrate(struct page *newpage, struct page *page,
 	struct z3fold_header *zhdr, *new_zhdr;
 	struct z3fold_pool *pool;
 
-	VM_BUG_ON_PAGE(!PageMovable(page), page);
 	VM_BUG_ON_PAGE(!PageIsolated(page), page);
 	VM_BUG_ON_PAGE(!test_bit(PAGE_CLAIMED, &page->private), page);
 	VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);

mm/zsmalloc.c

@@ -1973,7 +1973,6 @@ static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
 	 * Page is locked so zspage couldn't be destroyed. For detail, look at
 	 * lock_zspage in free_zspage.
 	 */
-	VM_BUG_ON_PAGE(!PageMovable(page), page);
 	VM_BUG_ON_PAGE(PageIsolated(page), page);
 
 	zspage = get_zspage(page);
@@ -2005,7 +2004,6 @@ static int zs_page_migrate(struct page *newpage, struct page *page,
 	if (mode == MIGRATE_SYNC_NO_COPY)
 		return -EINVAL;
 
-	VM_BUG_ON_PAGE(!PageMovable(page), page);
 	VM_BUG_ON_PAGE(!PageIsolated(page), page);
 
 	/* The page is locked, so this pointer must remain valid */
@@ -2070,7 +2068,6 @@ static void zs_page_putback(struct page *page)
 {
 	struct zspage *zspage;
 
-	VM_BUG_ON_PAGE(!PageMovable(page), page);
 	VM_BUG_ON_PAGE(!PageIsolated(page), page);
 
 	zspage = get_zspage(page);