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

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "richard" <richard at nod.at>
> An: "Rickard X Andersson" <rickard.andersson at axis.com>
> CC: "chengzhihao1" <chengzhihao1 at huawei.com>, "linux-mtd" <linux-mtd at lists.infradead.org>, "rickard314 andersson"
> <rickard314.andersson at gmail.com>, "kernel" <kernel at axis.com>
> Gesendet: Montag, 25. November 2024 16:44:54
> Betreff: Re: [PATCH 1/2] ubi: Expose interface for detailed erase counters

> ----- 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.

*fiemap
 
Thanks,
//richard