[PATCH v2 3/3] mtd: mtdpart: fix partitions searching

[Quentin Schulz]

Hi Mikhail,

On 1/19/26 1:36 AM, Mikhail Kshevetskiy wrote:
> mtdpart internally enumerate partitions starting from zero, but partition
> driver API enumerate partitions starting from 1. Just now mtdpart does
> not take this difference into account. This is wrong.
> 

This possibly will break a few boards which may be relying on the wrong 
offset being used. Since it was wrong (according to the doc in 
include/part.h which states the partition number 1 is the first), I 
guess it's "fine" to break those?

> Unnecessary debug message also was removed.
> 
> Fixes: c29a6daec184 ("disk: support MTD partitions")
> Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
> ---
>   drivers/mtd/mtdpart.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index 842d3e7274e..0bd4b3db022 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -1067,7 +1067,6 @@ static struct mtd_info *mtd_get_partition_by_index(struct mtd_info *mtd, int ind
>   		if (i++ == index)
>   			return part;
>   
> -	debug("Partition with idx=%d not found on MTD device %s\n", index, mtd->name);
>   	return NULL;
>   }
>   
> @@ -1082,9 +1081,11 @@ static int __maybe_unused part_get_info_mtd(struct blk_desc *dev_desc, int part_
>   		return -EINVAL;
>   	}
>   
> -	part = mtd_get_partition_by_index(master, part_idx);
> +	/* internal indexing starts from zero, but part_idx starts from 1 */
> +	part = mtd_get_partition_by_index(master, part_idx - 1);
>   	if (!part) {
> -		debug("Failed to find partition with idx=%d\n", part_idx);
> +		debug("Failed to find partition with idx=%d on MTD device %s\n",
> +		      part_idx - 1, master->name);

I think it'd make more sense to patch mtd_get_partition_by_index() to 
start with i = 1 instead of i = 0, because if we ever get another user 
of this function, then we don't need to go through the same trick that 
is implemented in this patch for part_get_info_mtd(). What do you think?

Cheers,
Quentin