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Message-ID: <6c299e8f-80be-0276-c8b1-9df1946434da@huawei.com>
Date:   Fri, 23 Sep 2022 11:00:52 +0100
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Subject: Re: [PATCH 6/7] scsi: pm8001: use dev_and_phy_addr_same() instead of
 open coded
To:     Jason Yan <yanaijie@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>
From:   John Garry <john.garry@huawei.com>
In-Reply-To: <3c1aa262-7e9b-cb6c-e8a1-a1a201050a10@huawei.com>
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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

> 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