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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>
 <20220917104311.1878250-7-yanaijie@huawei.com>
 <0034eff3-70a5-becb-0821-f9c36371e6d9@huawei.com>
 <3c1aa262-7e9b-cb6c-e8a1-a1a201050a10@huawei.com>
 <6c299e8f-80be-0276-c8b1-9df1946434da@huawei.com>
From:   Jason Yan <yanaijie@huawei.com>
Message-ID: <d3c7285f-6318-8254-2bfa-d836f12fcd88@huawei.com>
Date:   Fri, 23 Sep 2022 18:13:35 +0800
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On 2022/9/23 18:00, John Garry wrote:
> On 23/09/2022 10:44, Jason Yan wrote:
>>>>           for (phy_id = 0; phy_id < parent_dev->ex_dev.num_phys;
>>>
>>> This code seems the same between many libsas LLDDs - could we factor 
>>> it out into libsas? If so, then maybe those new helpers could be put 
>>> in sas_internal.h
>>
>> For the part of putting helpers in sas_internal.h, this needs to make 
>> the helpers exported.
> 
> 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.


>> I think it's not worth to do this because they are very small. I'd 
>> still like to make them inline functions in libsas.h such as:
>>
>>
>> diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
>> index 2dbead74a2af..e9e76c898287 100644
>> --- a/include/scsi/libsas.h
>> +++ b/include/scsi/libsas.h
>> @@ -648,6 +648,22 @@ static inline bool sas_is_internal_abort(struct 
>> sas_task *task)
>>          return task->task_proto == SAS_PROTOCOL_INTERNAL_ABORT;
>>   }
>>
>> +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;
> 
> I will note that this code does not use your new helpers
> 
>> +}
>> +
>>   struct sas_domain_function_template {
>>          /* The class calls these to notify the LLDD of an event. */
>>          void (*lldd_port_formed)(struct asd_sas_phy *);
>>
>>
>>
>> And the LLDDs change like:
>>
>>
>> diff --git a/drivers/scsi/pm8001/pm8001_sas.c 
>> b/drivers/scsi/pm8001/pm8001_sas.c
>> index 8e3f2f9ddaac..4e7350609b3d 100644
>> --- a/drivers/scsi/pm8001/pm8001_sas.c
>> +++ b/drivers/scsi/pm8001/pm8001_sas.c
>> @@ -645,16 +645,8 @@ static int pm8001_dev_found_notify(struct 
>> domain_device *dev)
>>          pm8001_device->dcompletion = &completion;
>>          if (parent_dev && dev_is_expander(parent_dev->dev_type)) {
>>                  int phy_id;
>> -               struct ex_phy *phy;
>> -               for (phy_id = 0; phy_id < parent_dev->ex_dev.num_phys;
>> -               phy_id++) {
>> -                       phy = &parent_dev->ex_dev.ex_phy[phy_id];
>> -                       if (SAS_ADDR(phy->attached_sas_addr)
>> -                               == SAS_ADDR(dev->sas_addr)) {
>> -                               pm8001_device->attached_phy = phy_id;
>> -                               break;
>> -                       }
>> -               }
>> +
>> +               phy_id = sas_find_attathed_phy(&parent_dev->ex_dev, dev);
>>                  if (phy_id == parent_dev->ex_dev.num_phys) {
>>                          pm8001_dbg(pm8001_ha, FAIL,
>>                                     "Error: no attached dev:%016llx at 
>> ex:%016llx.\n",
>> @@ -662,6 +654,7 @@ static int pm8001_dev_found_notify(struct 
>> domain_device *dev)
>>                                     SAS_ADDR(parent_dev->sas_addr));
>>                          res = -1;
>>                  }
>> +               pm8001_device->attached_phy = phy_id;
>>          } else {
>>                  if (dev->dev_type == SAS_SATA_DEV) {
>>                          pm8001_device->attached_phy =
>>
>>
>> So I wonder if you have any reasons to insist exporting the helper
> Thanks,
> John
> .