[PATCH 1/2] ubi: Expose interface for detailed erase counters

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "Rickard X Andersson" <rickard.andersson at axis.com>
> +/**
> + * struct ubi_ecinfo_req - a data structure used in UBI device erase count
> + * information requests and responses.
> + *
> + * @start_ec_req: first erase counter block in range to read
> + * @end_ec_req: last erase counter block in the half-open range
> + * @end_ec_res: last erase counter block that was actually read
> + * @erase_counters: array of erase counter values
> + * @padding: reserved for future, not used, has to be zeroed
> + *
> + * Erase counters are read in range @start_ec_req to @end_ec_req. Range is
> half-open
> + * i.e erase counter of end_ec_req is not actually included.
> + * The read erase counters are placed in @erase_counters. If a block is bad or
> if the
> + * erase counter is unknown the value of the block will be set to -1.
> + */
> +struct ubi_ecinfo_req {
> +	__s32 start_ec_req;
> +	__s32 end_ec_req;
> +	__s32 end_ec_res;
> +	__s32 erase_counters[1000];

There is no need to have a limited number. Just use a flexible array.
If userspace asks for more entries than the provided buffer can hold, __put_user()
will fail anyways.

Have a look at fibmap, I think you can the model the API the same way.

Thanks,
//richard