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Date:   Mon, 25 Apr 2022 09:51:26 +0100
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Subject: Re: [PATCH 1/4] scsi: libsas: Add sas_execute_internal_abort_single()
To:     Hannes Reinecke <hare@suse.de>, <jejb@linux.ibm.com>,
        <martin.petersen@oracle.com>, <jinpu.wang@cloud.ionos.com>,
        <damien.lemoal@opensource.wdc.com>
CC:     <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <Ajish.Koshy@microchip.com>, <linuxarm@huawei.com>,
        <Viswas.G@microchip.com>, <hch@lst.de>, <liuqi115@huawei.com>,
        <chenxiang66@hisilicon.com>
References: <1646309930-138960-1-git-send-email-john.garry@huawei.com>
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 <39975d62-b706-7d03-01a8-f6095c7af4ac@suse.de>
From:   John Garry <john.garry@huawei.com>
In-Reply-To: <39975d62-b706-7d03-01a8-f6095c7af4ac@suse.de>
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On 25/04/2022 09:34, Hannes Reinecke wrote:
>>>> +/* LLDDs rely on these values */
>>>> +enum sas_internal_abort {
>>>> +    SAS_INTERNAL_ABORT_SINGLE    = 0,
>>>> +};
>>>> +
>>>
>>> Why don't you use the existing TMF_XXX values here?
>>> Your 'single' method pretty much _is_ a TMF_ABORT_TASK, and the 
>>> 'device' method _is_ a TMF_ABORT_TASK_SET, no?
>>
>> Sure, they are doing the same as TMFs and there is equivalence in the 
>> 'single' and 'device' methods, as you say.
>>
>> However, as mentioned in the comment, the LLDDs rely on the values in 
>> enum sas_internal_abort, which do not match the values in 
>> TMF_ABORT{_TASK, _TASK_SET}.
>>
> How can they rely on a value which you just introduced?

I am relying on no one changing those values in enum sas_internal_abort.

Both hisi_sas and pm8001 use value of 0 for single abort and 1 for 
device abort in their own internal abort HW frames structs.

And if some other controller comes along which wants to support this 
feature and the values in enum sas_internal_abort don't match then they 
would need to do some translation.

I could use TMF values and do the translation in hisi_sas and pm8001 
drivers today, but I don't see much much gain in that.

Thanks,
John