[PATCH v3 1/4] disk: part: implement generic function part_get_info_by_uuid()

[Casey Connolly]

Hi Varadarajan,

On 5/7/25 13:28, Varadarajan Narayanan wrote:
> Add function to search for a partition by UUID as partition
> names may not be unique.
> 
> Signed-off-by: Varadarajan Narayanan <quic_varada at quicinc.com>
> ---
>   disk/part.c    | 37 +++++++++++++++++++++++++++++++++++++
>   include/part.h | 20 ++++++++++++++++++++
>   2 files changed, 57 insertions(+)
> 
> diff --git a/disk/part.c b/disk/part.c
> index 303178161c0..abae79a55a7 100644
> --- a/disk/part.c
> +++ b/disk/part.c
> @@ -698,6 +698,43 @@ int part_get_info_by_name(struct blk_desc *desc, const char *name,
>   	return -ENOENT;
>   }
>   
> +int part_get_info_by_uuid(struct blk_desc *desc, const char *uuid,
> +			  struct disk_partition *info)
> +{
> +#if CONFIG_IS_ENABLED(PARTITION_UUIDS)

Please refer to checkpatch output (the b4 tool will run this for you 
automatically).

	if (!CONFIG_IS_ENABLED(PARTITION_UUIDS))
		return -ENOENT;

> +	struct part_driver *part_drv;
> +	int ret;
> +	int i;
> +
> +	part_drv = part_driver_lookup_type(desc);
> +	if (!part_drv)
> +		return -1;
> +
> +	if (!part_drv->get_info) {
> +		log_debug("## Driver %s does not have the get_info() method\n",
> +			  part_drv->name);
> +		return -ENOSYS;
> +	}
> +
> +	for (i = 1; i < part_drv->max_entries; i++) {
> +		ret = part_drv->get_info(desc, i, info);
> +		if (ret != 0) {
> +			/*
> +			 * Partition with this index can't be obtained, but
> +			 * further partitions might be, so keep checking.
> +			 */
> +			continue;

For part_efi (which is the only one relevant here I think?) you can 
check for -EPERM which signals the end of the partition list I believe. 
Then we aren't calling get_info() 128 times for every LUN...

Kind regards,> +		}
> +
> +		if (!strncasecmp(uuid, disk_partition_uuid(info), UUID_STR_LEN)) {
> +			/* matched */
> +			return i;
> +		}
> +	}
> +#endif
> +	return -ENOENT;
> +}
> +
>   /**
>    * Get partition info from device number and partition name.
>    *
> diff --git a/include/part.h b/include/part.h
> index fcb3c13dea4..3e6eb0ec33f 100644
> --- a/include/part.h
> +++ b/include/part.h
> @@ -315,6 +315,20 @@ int blk_get_device_part_str(const char *ifname, const char *dev_part_str,
>   int part_get_info_by_name(struct blk_desc *desc, const char *name,
>   			  struct disk_partition *info);
>   
> +/**
> + * part_get_info_by_uuid() - Search for a partition by uuid
> + *                           among all available registered partitions
> + *
> + * @desc:	block device descriptor
> + * @uuid:	the specified table entry uuid
> + * @info:	the disk partition info
> + *
> + * Return: the partition number on match (starting on 1), -ENOENT on no match,
> + * otherwise error
> + */
> +int part_get_info_by_uuid(struct blk_desc *desc, const char *uuid,
> +			  struct disk_partition *info);
> +
>   /**
>    * part_get_info_by_dev_and_name_or_num() - Get partition info from dev number
>    *					    and part name, or dev number and
> @@ -386,6 +400,12 @@ static inline int part_get_info_by_name(struct blk_desc *desc, const char *name,
>   	return -ENOENT;
>   }
>   
> +static inline int part_get_info_by_uuid(struct blk_desc *desc, const char *uuid,
> +					struct disk_partition *info)
> +{
> +	return -ENOENT;
> +}
> +
>   static inline int
>   part_get_info_by_dev_and_name_or_num(const char *dev_iface,
>   				     const char *dev_part_str,

-- 
Casey (she/they)