erofs: cleanup i_format-related stuffs

Switch EROFS_I_{VERSION,DATALAYOUT}_BITS into
EROFS_I_{VERSION,DATALAYOUT}_MASK.

Also avoid erofs_bitrange() since its functionality is simple enough.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20230414083027.12307-2-hsiangkao@linux.alibaba.com

fs/erofs/erofs_fs.h

@@ -109,14 +109,14 @@ static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
 }
 
 /* bit definitions of inode i_format */
-#define EROFS_I_VERSION_BITS            1
-#define EROFS_I_DATALAYOUT_BITS         3
+#define EROFS_I_VERSION_MASK            0x01
+#define EROFS_I_DATALAYOUT_MASK         0x07
 
 #define EROFS_I_VERSION_BIT             0
 #define EROFS_I_DATALAYOUT_BIT          1
+#define EROFS_I_ALL_BIT			4
 
-#define EROFS_I_ALL	\
-	((1 << (EROFS_I_DATALAYOUT_BIT + EROFS_I_DATALAYOUT_BITS)) - 1)
+#define EROFS_I_ALL	((1 << EROFS_I_ALL_BIT) - 1)
 
 /* indicate chunk blkbits, thus 'chunksize = blocksize << chunk blkbits' */
 #define EROFS_CHUNK_FORMAT_BLKBITS_MASK		0x001F

fs/erofs/internal.h

@@ -343,24 +343,14 @@ static inline erofs_off_t erofs_iloc(struct inode *inode)
 		(EROFS_I(inode)->nid << sbi->islotbits);
 }
 
-static inline unsigned int erofs_bitrange(unsigned int value, unsigned int bit,
-					  unsigned int bits)
+static inline unsigned int erofs_inode_version(unsigned int ifmt)
 {
-
-	return (value >> bit) & ((1 << bits) - 1);
-}
-
-
-static inline unsigned int erofs_inode_version(unsigned int value)
-{
-	return erofs_bitrange(value, EROFS_I_VERSION_BIT,
-			      EROFS_I_VERSION_BITS);
+	return (ifmt >> EROFS_I_VERSION_BIT) & EROFS_I_VERSION_MASK;
 }
 
-static inline unsigned int erofs_inode_datalayout(unsigned int value)
+static inline unsigned int erofs_inode_datalayout(unsigned int ifmt)
 {
-	return erofs_bitrange(value, EROFS_I_DATALAYOUT_BIT,
-			      EROFS_I_DATALAYOUT_BITS);
+	return (ifmt >> EROFS_I_DATALAYOUT_BIT) & EROFS_I_DATALAYOUT_MASK;
 }
 
 /*