Re: [PATCH v1 1/2] fs: fat: add macro to convert u8[2] to u16

Alexander Dahl
2023-11-08T12:48:01Z

Hello Christian,

Am Wed, Nov 08, 2023 at 01:12:38PM +0100 schrieb christian.taedcke-oss@weidmueller.com:
> From: Christian Taedcke <christian.taedcke@weidmueller.com>
>
> This reduces code duplications.
>
> Signed-off-by: Christian Taedcke <christian.taedcke@weidmueller.com>
> ---
>
> fs/fat/fat.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/fs/fat/fat.c b/fs/fat/fat.c
> index 8ff1fd0ec8..8a0f4e4e6c 100644
> --- a/fs/fat/fat.c
> +++ b/fs/fat/fat.c
> @@ -25,6 +25,8 @@
> #include <linux/compiler.h>
> #include <linux/ctype.h>
>
> +#define FATU8ARRAY2CPU16(x) (((x)[1] << 8) + (x)[0])

This does the same as the generic `get_unaligned_le16()` … why not use
that?

Greets
Alex

> +
> /*
> * Convert a string to lowercase. Converts at most 'len' characters,
> * 'len' may be larger than the length of 'str' if 'str' is NULL
> @@ -571,7 +573,7 @@ static int get_fs_info(fsdata *mydata)
> mydata->total_sect = bs.total_sect;
> } else {
> mydata->fatlength = bs.fat_length;
> - mydata->total_sect = (bs.sectors[1] << 8) + bs.sectors[0];
> + mydata->total_sect = FATU8ARRAY2CPU16(bs.sectors);
> if (!mydata->total_sect)
> mydata->total_sect = bs.total_sect;
> }
> @@ -583,7 +585,7 @@ static int get_fs_info(fsdata *mydata)
>
> mydata->rootdir_sect = mydata->fat_sect + mydata->fatlength * bs.fats;
>
> - mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
> + mydata->sect_size = FATU8ARRAY2CPU16(bs.sector_size);
> mydata->clust_size = bs.cluster_size;
> if (mydata->sect_size != cur_part_info.blksz) {
> log_err("FAT sector size mismatch (fs=%u, dev=%lu)\n",
> @@ -607,8 +609,7 @@ static int get_fs_info(fsdata *mydata)
> (mydata->clust_size * 2);
> mydata->root_cluster = bs.root_cluster;
> } else {
> - mydata->rootdir_size = ((bs.dir_entries[1] * (int)256 +
> - bs.dir_entries[0]) *
> + mydata->rootdir_size = (FATU8ARRAY2CPU16(bs.dir_entries) *
> sizeof(dir_entry)) /
> mydata->sect_size;
> mydata->data_begin = mydata->rootdir_sect +
> --
> 2.34.1
>