erofs: don't use erofs_map_blocks() any more

Currently, erofs_map_blocks() will be called only from
erofs_{bmap, read_raw_page} which are all for uncompressed files.
So, the compression branch in erofs_map_blocks() is pointless. Let's
remove it and use erofs_map_blocks_flatmode() directly. Also update
related comments.

Link: https://lore.kernel.org/r/20210325071008.573-1-zbestahu@gmail.comReviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>

fs/erofs/data.c

@@ -109,21 +109,6 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 	return err;
 }
 
-int erofs_map_blocks(struct inode *inode,
-		     struct erofs_map_blocks *map, int flags)
-{
-	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
-		int err = z_erofs_map_blocks_iter(inode, map, flags);
-
-		if (map->mpage) {
-			put_page(map->mpage);
-			map->mpage = NULL;
-		}
-		return err;
-	}
-	return erofs_map_blocks_flatmode(inode, map, flags);
-}
-
 static inline struct bio *erofs_read_raw_page(struct bio *bio,
 					      struct address_space *mapping,
 					      struct page *page,
@@ -159,7 +144,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 		erofs_blk_t blknr;
 		unsigned int blkoff;
 
-		err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
+		err = erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW);
 		if (err)
 			goto err_out;
 
@@ -318,7 +303,7 @@ static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
 			return 0;
 	}
 
-	if (!erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW))
+	if (!erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW))
 		return erofs_blknr(map.m_pa);
 
 	return 0;

fs/erofs/internal.h

@@ -289,7 +289,7 @@ extern const struct address_space_operations erofs_raw_access_aops;
 extern const struct address_space_operations z_erofs_aops;
 
 /*
- * Logical to physical block mapping, used by erofs_map_blocks()
+ * Logical to physical block mapping
  *
  * Different with other file systems, it is used for 2 access modes:
  *
@@ -336,7 +336,7 @@ struct erofs_map_blocks {
 	struct page *mpage;
 };
 
-/* Flags used by erofs_map_blocks() */
+/* Flags used by erofs_map_blocks_flatmode() */
 #define EROFS_GET_BLOCKS_RAW    0x0001
 
 /* zmap.c */
@@ -358,8 +358,6 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode,
 /* data.c */
 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr);
 
-int erofs_map_blocks(struct inode *, struct erofs_map_blocks *, int);
-
 /* inode.c */
 static inline unsigned long erofs_inode_hash(erofs_nid_t nid)
 {