f2fs: drop usage of folio_index

folio_index is only needed for mixed usage of page cache and swap
cache, for pure page cache usage, the caller can just use
folio->index instead.

It can't be a swap cache folio here.  Swap mapping may only call into fs
through `swap_rw` but f2fs does not use that method for swap.

Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org> (maintainer:F2FS FILE SYSTEM)
Cc: Chao Yu <chao@kernel.org> (maintainer:F2FS FILE SYSTEM)
Cc: linux-f2fs-devel@lists.sourceforge.net (open list:F2FS FILE SYSTEM)
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: ryncsn

fs/f2fs/data.c

@@ -2078,7 +2078,7 @@ static int f2fs_read_single_page(struct inode *inode, struct folio *folio,
 	sector_t last_block;
 	sector_t last_block_in_file;
 	sector_t block_nr;
-	pgoff_t index = folio_index(folio);
+	pgoff_t index = folio->index;
 	int ret = 0;
 
 	block_in_file = (sector_t)index;
@@ -2392,7 +2392,7 @@ static int f2fs_mpage_readpages(struct inode *inode,
 		}
 
 #ifdef CONFIG_F2FS_FS_COMPRESSION
-		index = folio_index(folio);
+		index = folio->index;
 
 		if (!f2fs_compressed_file(inode))
 			goto read_single_page;

fs/f2fs/inline.c

@@ -86,7 +86,7 @@ void f2fs_do_read_inline_data(struct folio *folio, struct folio *ifolio)
 	if (folio_test_uptodate(folio))
 		return;
 
-	f2fs_bug_on(F2FS_I_SB(inode), folio_index(folio));
+	f2fs_bug_on(F2FS_I_SB(inode), folio->index);
 
 	folio_zero_segment(folio, MAX_INLINE_DATA(inode), folio_size(folio));
 
@@ -130,7 +130,7 @@ int f2fs_read_inline_data(struct inode *inode, struct folio *folio)
 		return -EAGAIN;
 	}
 
-	if (folio_index(folio))
+	if (folio->index)
 		folio_zero_segment(folio, 0, folio_size(folio));
 	else
 		f2fs_do_read_inline_data(folio, ifolio);

fs/f2fs/super.c

@@ -3432,7 +3432,7 @@ static int __f2fs_commit_super(struct f2fs_sb_info *sbi, struct folio *folio,
 	bio = bio_alloc(sbi->sb->s_bdev, 1, opf, GFP_NOFS);
 
 	/* it doesn't need to set crypto context for superblock update */
-	bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(folio_index(folio));
+	bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(folio->index);
 
 	if (!bio_add_folio(bio, folio, folio_size(folio), 0))
 		f2fs_bug_on(sbi, 1);