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From:   OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To:     Carmeli Tamir <carmeli.tamir@gmail.com>
Cc:     linux-kernel@vger.kernel.org, jthumshirn@suse.de,
        sergey.senozhatsky@gmail.com, akpm@linux-foundation.org,
        bvanassche@acm.org, axboe@kernel.dk, martin.petersen@oracle.com,
        sfr@canb.auug.org.au
Subject: Re: [PATCH v2 3/3] fat: New inline functions to determine the FAT variant (32, 16 or 12)
References: <1544879072-4251-1-git-send-email-carmeli.tamir@gmail.com>
        <1544879072-4251-4-git-send-email-carmeli.tamir@gmail.com>
Date:   Sun, 16 Dec 2018 04:10:39 +0900
In-Reply-To: <1544879072-4251-4-git-send-email-carmeli.tamir@gmail.com>
        (Carmeli Tamir's message of "Sat, 15 Dec 2018 08:04:32 -0500")
Message-ID: <87y38qbo7k.fsf@mail.parknet.co.jp>
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Carmeli Tamir <carmeli.tamir@gmail.com> writes:

> 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.

Could you use lower case chars for inline functions?

> Signed-off-by: Carmeli Tamir <carmeli.tamir@gmail.com>
> ---
>  fs/fat/cache.c  |  2 +-
>  fs/fat/dir.c    |  4 ++--
>  fs/fat/fat.h    | 25 ++++++++++++++++++++++---
>  fs/fat/fatent.c | 16 +++++++---------
>  fs/fat/inode.c  | 12 ++++++------
>  fs/fat/misc.c   |  2 +-
>  6 files changed, 39 insertions(+), 22 deletions(-)
>
> diff --git a/fs/fat/cache.c b/fs/fat/cache.c
> index 78d501c..30c51b9 100644
> --- a/fs/fat/cache.c
> +++ b/fs/fat/cache.c
> @@ -363,7 +363,7 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
>  
>  	*phys = 0;
>  	*mapped_blocks = 0;
> -	if ((sbi->fat_bits != 32) && (inode->i_ino == MSDOS_ROOT_INO)) {
> +	if (!IS_FAT32(sbi) && (inode->i_ino == MSDOS_ROOT_INO)) {
>  		if (sector < (sbi->dir_entries >> sbi->dir_per_block_bits)) {
>  			*phys = sector + sbi->dir_start;
>  			*mapped_blocks = 1;
> diff --git a/fs/fat/dir.c b/fs/fat/dir.c
> index c8366cb..b0b8f44 100644
> --- a/fs/fat/dir.c
> +++ b/fs/fat/dir.c
> @@ -57,7 +57,7 @@ static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
>  	if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
>  		return;
>  	/* root dir of FAT12/FAT16 */
> -	if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
> +	if (!IS_FAT32(sbi) && (dir->i_ino == MSDOS_ROOT_INO))
>  		return;
>  
>  	bh = sb_find_get_block(sb, phys);
> @@ -1313,7 +1313,7 @@ int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
>  		}
>  	}
>  	if (dir->i_ino == MSDOS_ROOT_INO) {
> -		if (sbi->fat_bits != 32)
> +		if (!IS_FAT32(sbi))
>  			goto error;
>  	} else if (MSDOS_I(dir)->i_start == 0) {
>  		fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
> diff --git a/fs/fat/fat.h b/fs/fat/fat.h
> index 11bc4a2..5b6f1c8 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;
>  }
> diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
> index f58c0ca..9166d96 100644
> --- a/fs/fat/fatent.c
> +++ b/fs/fat/fatent.c
> @@ -290,19 +290,17 @@ void fat_ent_access_init(struct super_block *sb)
>  
>  	mutex_init(&sbi->fat_lock);
>  
> -	switch (sbi->fat_bits) {
> -	case 32:
> +	if (IS_FAT32(sbi)) {
>  		sbi->fatent_shift = 2;
>  		sbi->fatent_ops = &fat32_ops;
> -		break;
> -	case 16:
> +	} else if (IS_FAT16(sbi)) {
>  		sbi->fatent_shift = 1;
>  		sbi->fatent_ops = &fat16_ops;
> -		break;
> -	case 12:
> +	} else if (IS_FAT12(sbi)) {
>  		sbi->fatent_shift = -1;
>  		sbi->fatent_ops = &fat12_ops;
> -		break;
> +	} else {
> +		fat_fs_error(sb, "invalid FAT variant, %u bits", sbi->fat_bits);
>  	}
>  }
>  
> @@ -310,7 +308,7 @@ static void mark_fsinfo_dirty(struct super_block *sb)
>  {
>  	struct msdos_sb_info *sbi = MSDOS_SB(sb);
>  
> -	if (sb_rdonly(sb) || sbi->fat_bits != 32)
> +	if (sb_rdonly(sb) || !IS_FAT32(sbi))
>  		return;
>  
>  	__mark_inode_dirty(sbi->fsinfo_inode, I_DIRTY_SYNC);
> @@ -327,7 +325,7 @@ static inline int fat_ent_update_ptr(struct super_block *sb,
>  	/* Is this fatent's blocks including this entry? */
>  	if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr)
>  		return 0;
> -	if (sbi->fat_bits == 12) {
> +	if (IS_FAT12(sbi)) {
>  		if ((offset + 1) < sb->s_blocksize) {
>  			/* This entry is on bhs[0]. */
>  			if (fatent->nr_bhs == 2) {
> diff --git a/fs/fat/inode.c b/fs/fat/inode.c
> index 708de6d..a84b61b 100644
> --- a/fs/fat/inode.c
> +++ b/fs/fat/inode.c
> @@ -686,7 +686,7 @@ static void fat_set_state(struct super_block *sb,
>  
>  	b = (struct fat_boot_sector *) bh->b_data;
>  
> -	if (sbi->fat_bits == 32) {
> +	if (IS_FAT32(sbi)) {
>  		if (set)
>  			b->fat32.state |= FAT_STATE_DIRTY;
>  		else
> @@ -1397,7 +1397,7 @@ static int fat_read_root(struct inode *inode)
>  	inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
>  	inode->i_op = sbi->dir_ops;
>  	inode->i_fop = &fat_dir_operations;
> -	if (sbi->fat_bits == 32) {
> +	if (IS_FAT32(sbi)) {
>  		MSDOS_I(inode)->i_start = sbi->root_cluster;
>  		error = fat_calc_dir_size(inode);
>  		if (error < 0)
> @@ -1424,7 +1424,7 @@ static unsigned long calc_fat_clusters(struct super_block *sb)
>  	struct msdos_sb_info *sbi = MSDOS_SB(sb);
>  
>  	/* Divide first to avoid overflow */
> -	if (sbi->fat_bits != 12) {
> +	if (!IS_FAT12(sbi)) {
>  		unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
>  		return ent_per_sec * sbi->fat_length;
>  	}
> @@ -1744,7 +1744,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
>  	}
>  
>  	/* interpret volume ID as a little endian 32 bit integer */
> -	if (sbi->fat_bits == 32)
> +	if (IS_FAT32(sbi))
>  		sbi->vol_id = bpb.fat32_vol_id;
>  	else /* fat 16 or 12 */
>  		sbi->vol_id = bpb.fat16_vol_id;
> @@ -1770,11 +1770,11 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
>  
>  	total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
>  
> -	if (sbi->fat_bits != 32)
> +	if (!IS_FAT32(sbi))
>  		sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
>  
>  	/* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
> -	if (sbi->fat_bits == 32)
> +	if (IS_FAT32(sbi))
>  		sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
>  	else /* fat 16 or 12 */
>  		sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
> diff --git a/fs/fat/misc.c b/fs/fat/misc.c
> index fce0a76..5368c6a 100644
> --- a/fs/fat/misc.c
> +++ b/fs/fat/misc.c
> @@ -64,7 +64,7 @@ int fat_clusters_flush(struct super_block *sb)
>  	struct buffer_head *bh;
>  	struct fat_boot_fsinfo *fsinfo;
>  
> -	if (sbi->fat_bits != 32)
> +	if (!IS_FAT32(sbi))
>  		return 0;
>  
>  	bh = sb_bread(sb, sbi->fsinfo_sector);

-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>