fat: new inline functions to determine the FAT variant (32, 16 or 12)

This patch introduces 3 new inline functions - is_fat12, is_fat16 and
is_fat32, and replaces every occurrence in the code in which the FS
variant (whether this is FAT12, FAT16 or FAT32) was previously checked
using msdos_sb_info->fat_bits.

Link: http://lkml.kernel.org/r/1544990640-11604-4-git-send-email-carmeli.tamir@gmail.com
Signed-off-by: Carmeli Tamir <carmeli.tamir@gmail.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 3 deletions

diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 979bb11832f6..922a0c6ba46c 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -142,13 +142,32 @@ static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
 	return sb->s_fs_info;
 }
 
+/*
+ * Functions that determine the variant of the FAT file system (i.e.,
+ * whether this is FAT12, FAT16 or FAT32.
+ */
+static inline bool is_fat12(const struct msdos_sb_info *sbi)
+{
+	return sbi->fat_bits == 12;
+}
+
+static inline bool is_fat16(const struct msdos_sb_info *sbi)
+{
+	return sbi->fat_bits == 16;
+}
+
+static inline bool is_fat32(const struct msdos_sb_info *sbi)
+{
+	return sbi->fat_bits == 32;
+}
+
 /* Maximum number of clusters */
 static inline u32 max_fat(struct super_block *sb)
 {
 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
 
-	return sbi->fat_bits == 32 ? MAX_FAT32 :
-		sbi->fat_bits == 16 ? MAX_FAT16 : MAX_FAT12;
+	return is_fat32(sbi) ? MAX_FAT32 :
+		is_fat16(sbi) ? MAX_FAT16 : MAX_FAT12;
 }
 
 static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
@@ -266,7 +285,7 @@ static inline int fat_get_start(const struct msdos_sb_info *sbi,
 				const struct msdos_dir_entry *de)
 {
 	int cluster = le16_to_cpu(de->start);
-	if (sbi->fat_bits == 32)
+	if (is_fat32(sbi))
 		cluster |= (le16_to_cpu(de->starthi) << 16);
 	return cluster;
 }