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Subject: Re: [PATCH 6/7] scsi: pm8001: use dev_and_phy_addr_same() instead of
 open coded
To:     John Garry <john.garry@huawei.com>, <martin.petersen@oracle.com>,
        <jejb@linux.ibm.com>
CC:     <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <hare@suse.com>, <hch@lst.de>, <bvanassche@acm.org>,
        <jinpu.wang@cloud.ionos.com>
References: <20220917104311.1878250-1-yanaijie@huawei.com>
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 <d3c7285f-6318-8254-2bfa-d836f12fcd88@huawei.com>
 <569cb47c-af63-cf70-ae1a-4c5116dd4877@huawei.com>
From:   Jason Yan <yanaijie@huawei.com>
Message-ID: <d303aa1d-a397-4bb0-394d-46bd8c0db27d@huawei.com>
Date:   Sat, 24 Sep 2022 11:22:32 +0800
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On 2022/9/23 18:30, John Garry wrote:
> On 23/09/2022 11:13, Jason Yan wrote:
>>>
>>> Please explain why.
>>>
>>> I would assume that if those helpers were only used in libsas code 
>>> (and not LLDDs) then they could be put in sas_internal.h and no need 
>>> for export
>>>
>>
>>
>> Sorry, I did not make it clear. I mean we need to export 
>> sas_find_attathed_phy() below. Not the sas address comparation helpers.
> 
> That seems fine to me.
> 
> About sas_find_attathed_phy() implementation,
> 
>  > +static inline int sas_find_attathed_phy(struct expander_device *ex_dev,
>  > +                                       struct domain_device *dev)
>  > +{
>  > +       struct ex_phy *phy;
>  > +       int phy_id;
>  > +
>  > +       for (phy_id = 0; phy_id < ex_dev->num_phys; phy_id++) {
>  > +               phy = &ex_dev->ex_phy[phy_id];
>  > +               if (SAS_ADDR(phy->attached_sas_addr)
>  > +                       == SAS_ADDR(dev->sas_addr))
>  > +                       return phy_id;
>  > +       }
>  > +
>  > +       return ex_dev->num_phys;
> 
> Returning ex_dev->num_phys would seem ok, but then the LLDD needs to 
> check that return against ex_dev->num_phys. It seems ok, but I'm still 
> not 100% comfortable with that. Maybe returning -ENODEV may be better.
> 
> Or return boolean and pass phy_id as pointer to be filled in when 
> returning true.
> 

I've been thinking about this for a while too. Thank you for the advise.

Thanks,
Jason

>  > +}
> 
> Thanks,
> John
> 
> .