Message-ID: <21f73bfd-1d91-106f-d3a8-eb4674c517e6@acm.org>
Date:   Mon, 27 Feb 2023 08:59:41 -0800
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Subject: Re: [PATCH 1/2] include: uapi: scsi: Change utp_upiu_query struct
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To:     Arthur Simchaev <Arthur.Simchaev@wdc.com>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>
Cc:     "beanhuo@micron.com" <beanhuo@micron.com>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
References: <1677078770-30994-1-git-send-email-Arthur.Simchaev@wdc.com>
 <1677078770-30994-2-git-send-email-Arthur.Simchaev@wdc.com>
 <b1f0ed44-d707-5593-7449-8a6bd23c9902@acm.org>
 <BY5PR04MB632717453EB0D403388B4F1EEDAF9@BY5PR04MB6327.namprd04.prod.outlook.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <BY5PR04MB632717453EB0D403388B4F1EEDAF9@BY5PR04MB6327.namprd04.prod.outlook.com>
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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.