Re: [PATCH] FAT: Rename ambiguous fat_sectors and fat_total_sect fields

[OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>]

Ziran Zhang <zhangcoder@yeah.net> writes:

> The fields 'fat_sectors' (BPB_TotSec16) and 'fat_total_sect'
> (BPB_TotSec32) in struct fat_bios_param_block have ambiguous
> names that do not clearly indicate their size or purpose, often
> leading to confusion with FAT table sectors.
>
> These fields correspond to BPB_TotSec16 and BPB_TotSec32 as
> defined in Microsoft's fatgen103.doc.
>
> Rename them for clarity:
>  - fat_sectors → fat_total_sect16 (16-bit total sector count)
>  - fat_total_sect → fat_total_sect32 (32-bit total sector count)
>
> This makes their roles immediately obvious. No functional change,
> and the struct is internal to the kernel so ABI is unaffected.
>
> Signed-off-by: Ziran Zhang <zhangcoder@yeah.net>

Change is more readable I think too. However, inconsistent can be more
confusable. And I think no value to change user visible header, so this
is remaining.

Thanks.

> ---
>  fs/fat/inode.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/fs/fat/inode.c b/fs/fat/inode.c
> index 28f78df08..90286ba0e 100644
> --- a/fs/fat/inode.c
> +++ b/fs/fat/inode.c
> @@ -47,9 +47,9 @@ struct fat_bios_param_block {
>  	u16	fat_reserved;
>  	u8	fat_fats;
>  	u16	fat_dir_entries;
> -	u16	fat_sectors;
> +	u16	fat_total_sect16;
>  	u16	fat_fat_length;
> -	u32	fat_total_sect;
> +	u32	fat_total_sect32;
>  
>  	u8	fat16_state;
>  	u32	fat16_vol_id;
> @@ -1403,9 +1403,9 @@ static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
>  	bpb->fat_reserved = le16_to_cpu(b->reserved);
>  	bpb->fat_fats = b->fats;
>  	bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
> -	bpb->fat_sectors = get_unaligned_le16(&b->sectors);
> +	bpb->fat_total_sect16 = get_unaligned_le16(&b->sectors);
>  	bpb->fat_fat_length = le16_to_cpu(b->fat_length);
> -	bpb->fat_total_sect = le32_to_cpu(b->total_sect);
> +	bpb->fat_total_sect32 = le32_to_cpu(b->total_sect);
>  
>  	bpb->fat16_state = b->fat16.state;
>  	bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
> @@ -1523,7 +1523,7 @@ static int fat_read_static_bpb(struct super_block *sb,
>  	bpb->fat_reserved = 1;
>  	bpb->fat_fats = 2;
>  	bpb->fat_dir_entries = fdefaults->dir_entries;
> -	bpb->fat_sectors = fdefaults->nr_sectors;
> +	bpb->fat_total_sect16 = fdefaults->nr_sectors;
>  	bpb->fat_fat_length = fdefaults->fat_length;
>  
>  	error = 0;
> @@ -1734,9 +1734,9 @@ int fat_fill_super(struct super_block *sb, struct fs_context *fc,
>  	rootdir_sectors = sbi->dir_entries
>  		* sizeof(struct msdos_dir_entry) / sb->s_blocksize;
>  	sbi->data_start = sbi->dir_start + rootdir_sectors;
> -	total_sectors = bpb.fat_sectors;
> +	total_sectors = bpb.fat_total_sect16;
>  	if (total_sectors == 0)
> -		total_sectors = bpb.fat_total_sect;
> +		total_sectors = bpb.fat_total_sect32;
>  
>  	total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;

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