Re: [PATCH 1/2] include: uapi: scsi: Change utp_upiu_query struct

[Bart Van Assche <bvanassche@acm.org>]

On 2/27/23 08:03, Arthur Simchaev wrote:
>>>
>>>    */
>>>   struct utp_upiu_query {
>>>   	__u8 opcode;
>>>   	__u8 idn;
>>>   	__u8 index;
>>>   	__u8 selector;
>>> -	__be16 reserved_osf;
>>> -	__be16 length;
>>> -	__be32 value;
>>> -	__be32 reserved[2];
>>> +	__u8 osf3;
>>> +	__u8 osf4;
>>> +	__be16 osf5;
>>> +	__be32 osf6;
>>> +	__be32 osf7;
>>>   };
>> All changes in UAPI headers must be backwards compatible. The above doesn't look like a backwards compatible change to me.
>
> This API was originally invented to support ufs-bsg.
> AFAIK, ufs-utils is the only app that makes use of this API,
> and it doesn't dig into struct utp_upiu_query inner fields.

That does not match what I see. I see that code in ufs-utils accesses 
the 'length' and 'value' members of the above data structure.

Please follow the rules for UAPI header files.

Thanks,

Bart.