btrfs: convert wait_subpage_spinlock() to only use a folio

Currently this already uses a folio for most things, update it to take a
folio and update all the page usage with the corresponding folio usage.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -7187,13 +7187,12 @@ struct extent_map *btrfs_create_io_em(struct btrfs_inode *inode, u64 start,
  * for subpage spinlock.  So this function is to spin and wait for subpage
  * spinlock.
  */
-static void wait_subpage_spinlock(struct page *page)
+static void wait_subpage_spinlock(struct folio *folio)
 {
-	struct btrfs_fs_info *fs_info = page_to_fs_info(page);
-	struct folio *folio = page_folio(page);
+	struct btrfs_fs_info *fs_info = folio_to_fs_info(folio);
 	struct btrfs_subpage *subpage;
 
-	if (!btrfs_is_subpage(fs_info, page->mapping))
+	if (!btrfs_is_subpage(fs_info, folio->mapping))
 		return;
 
 	ASSERT(folio_test_private(folio) && folio_get_private(folio));
@@ -7223,7 +7222,7 @@ static int btrfs_launder_folio(struct folio *folio)
 static bool __btrfs_release_folio(struct folio *folio, gfp_t gfp_flags)
 {
 	if (try_release_extent_mapping(&folio->page, gfp_flags)) {
-		wait_subpage_spinlock(&folio->page);
+		wait_subpage_spinlock(folio);
 		clear_page_extent_mapped(&folio->page);
 		return true;
 	}
@@ -7284,7 +7283,7 @@ static void btrfs_invalidate_folio(struct folio *folio, size_t offset,
 	 * do double ordered extent accounting on the same folio.
 	 */
 	folio_wait_writeback(folio);
-	wait_subpage_spinlock(&folio->page);
+	wait_subpage_spinlock(folio);
 
 	/*
 	 * For subpage case, we have call sites like