[U-Boot] [PATCH 2/2] fs/fat/fat: Optimizes memory size with single global variable instead of 3

[Benoît Thébaudeau]

Dear Tien Fong Chee,

On Jul 13, 2016 at 11:01 AM, Tien Fong Chee wrote:
> Single 64KB get_contents_vfatname_block global variable would be used for
> all FAT implementation instead of allocating additional two global variables
> which are get_denfromdir_block and do_fat_read_at_block. This implementation
> can help in saving up 128KB memory space.
> 
> Signed-off-by: Tien Fong Chee <tfchee at altera.com>
> Cc: Dinh Nguyen <dinguyen at opensource.altera.com>
> Cc: Dinh Nguyen <dinh.linux at gmail.com>
> Cc: ChinLiang <clsee at altera.com>
> Cc: Vagrant Cascadian <vagrant at debian.org>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Stephen Warren <swarren at nvidia.com>
> Cc: Benoît Thébaudeau <benoit at wsystem.com>
> ---
>  fs/fat/fat.c |    6 ++----
>  1 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/fat/fat.c b/fs/fat/fat.c
> index 826bd85..5d1afe6 100644
> --- a/fs/fat/fat.c
> +++ b/fs/fat/fat.c
> @@ -579,8 +579,7 @@ static __u8 mkcksum(const char name[8], const char ext[3])
>   * Get the directory entry associated with 'filename' from the directory
>   * starting at 'startsect'
>   */
> -__u8 get_dentfromdir_block[MAX_CLUSTSIZE]
> -	__aligned(ARCH_DMA_MINALIGN);
> +__u8 *get_dentfromdir_block = get_contents_vfatname_block;
>  
>  static dir_entry *get_dentfromdir(fsdata *mydata, int startsect,
>  				  char *filename, dir_entry *retdent,
> @@ -811,8 +810,7 @@ exit:
>  	return ret;
>  }
>  
> -__u8 do_fat_read_at_block[MAX_CLUSTSIZE]
> -	__aligned(ARCH_DMA_MINALIGN);
> +__u8 *do_fat_read_at_block = get_contents_vfatname_block;
>  
>  int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
>  		   loff_t maxsize, int dols, int dogetsize, loff_t *size)

This probably breaks at least fat_write.c, which uses:
  memcpy(get_dentfromdir_block, get_contents_vfatname_block,

Best regards,
Benoît