Re: [PATCH 08/10] mtd: afs: factor footer parsing into the v1 part parsing

[Brian Norris <computersforpeace@gmail.com>]

Hi,

On Thu, Oct 15, 2015 at 03:08:51PM +0200, Linus Walleij wrote:
> This simplifies the code by factoring in the image footer
> parsing into the single function parsing the AFSv1 partitions.
> 
> Cc: Ryan Harkin <ryan.harkin@linaro.org>
> Cc: Liviu Dudau <liviu.dudau@arm.com>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>  drivers/mtd/afs.c | 98 ++++++++++++++++++++++---------------------------------
>  1 file changed, 39 insertions(+), 59 deletions(-)
> 
> diff --git a/drivers/mtd/afs.c b/drivers/mtd/afs.c
> index ace27f447abc..cdee8295d4c0 100644
> --- a/drivers/mtd/afs.c
> +++ b/drivers/mtd/afs.c
> @@ -89,63 +89,6 @@ static bool afs_is_v1(struct mtd_info *mtd, u_int off)
>  }
>  
>  static int
> -afs_read_footer_v1(struct mtd_info *mtd, u_int *img_start, u_int *iis_start,
> -		   u_int off, u_int mask)
> -{
> -	struct footer_v1 fs;
> -	u_int ptr = off + mtd->erasesize - sizeof(fs);
> -	size_t sz;
> -	int ret;
> -
> -	ret = mtd_read(mtd, ptr, sizeof(fs), &sz, (u_char *)&fs);
> -	if (ret >= 0 && sz != sizeof(fs))
> -		ret = -EINVAL;
> -
> -	if (ret < 0) {
> -		printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
> -			ptr, ret);
> -		return ret;
> -	}
> -
> -	/*
> -	 * Does it contain the magic number?
> -	 */
> -	if (fs.signature != AFSV1_FOOTER_MAGIC)
> -		return 0;
> -
> -	/*
> -	 * Check the checksum.
> -	 */
> -	if (word_sum(&fs, sizeof(fs) / sizeof(u32)) != 0xffffffff)
> -		return 0;
> -
> -	/*
> -	 * Don't touch the SIB.
> -	 */
> -	if (fs.type == 2)
> -		return 0;
> -
> -	*iis_start = fs.image_info_base & mask;
> -	*img_start = fs.image_start & mask;
> -
> -	/*
> -	 * Check the image info base.  This can not
> -	 * be located after the footer structure.
> -	 */
> -	if (*iis_start >= ptr)
> -		return 0;
> -
> -	/*
> -	 * Check the start of this image.  The image
> -	 * data can not be located after this block.
> -	 */
> -	if (*img_start > off)
> -		return 0;
> -
> -	return 1;
> -}
> -
> -static int
>  afs_read_iis_v1(struct mtd_info *mtd, struct image_info_v1 *iis, u_int ptr)
>  {
>  	size_t sz;
> @@ -184,6 +127,7 @@ afs_read_iis_v1(struct mtd_info *mtd, struct image_info_v1 *iis, u_int ptr)
>  static int afs_parse_v1_partition(struct mtd_info *mtd,
>  				  u_int off, struct mtd_partition *part)
>  {
> +	struct footer_v1 fs;
>  	struct image_info_v1 iis;
>  	u_int mask;
>  	/*
> @@ -192,6 +136,8 @@ static int afs_parse_v1_partition(struct mtd_info *mtd,
>  	 */
>  	u_int uninitialized_var(iis_ptr);
>  	u_int uninitialized_var(img_ptr);
> +	u_int ptr;
> +	size_t sz;
>  	int ret;
>  
>  	/*
> @@ -200,9 +146,43 @@ static int afs_parse_v1_partition(struct mtd_info *mtd,
>  	 */
>  	mask = mtd->size - 1;
>  
> -	ret = afs_read_footer_v1(mtd, &img_ptr, &iis_ptr, off, mask);
> -	if (ret < 0)
> +	ptr = off + mtd->erasesize - sizeof(fs);
> +	ret = mtd_read(mtd, ptr, sizeof(fs), &sz, (u_char *)&fs);
> +	if (ret >= 0 && sz != sizeof(fs))
> +		ret = -EINVAL;
> +	if (ret < 0) {
> +		printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
> +		       ptr, ret);
>  		return ret;
> +	}
> +	/*
> +	 * Check the checksum.
> +	 */
> +	if (word_sum(&fs, sizeof(fs) / sizeof(u32)) != 0xffffffff)
> +		return -EINVAL;

^^ This was modified. See my other comments about it.

Brian

> +
> +	/*
> +	 * Hide the SIB (System Information Block)
> +	 */
> +	if (fs.type == 2)
> +		return 0;
> +
> +	iis_ptr = fs.image_info_base & mask;
> +	img_ptr = fs.image_start & mask;
> +
> +	/*
> +	 * Check the image info base.  This can not
> +	 * be located after the footer structure.
> +	 */
> +	if (iis_ptr >= ptr)
> +		return 0;
> +
> +	/*
> +	 * Check the start of this image.  The image
> +	 * data can not be located after this block.
> +	 */
> +	if (img_ptr > off)
> +		return 0;
>  
>  	/* Read the image info block */
>  	ret = afs_read_iis_v1(mtd, &iis, iis_ptr);
> -- 
> 2.4.3
>