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Subject: Re: [PATCH] scsi: hisi_sas: display correct proc_name in sysfs
To:     Jason Yan <yanaijie@huawei.com>, <jejb@linux.ibm.com>,
        <martin.petersen@oracle.com>, <linux-scsi@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
CC:     Xiang Chen <chenxiang66@hisilicon.com>
References: <20200512063318.13825-1-yanaijie@huawei.com>
 <66c3318d-e8fa-9ff4-c7f4-ebe23925b807@huawei.com>
 <dacd7cbe-3d84-2b35-e63a-af6179aa5221@huawei.com>
From:   John Garry <john.garry@huawei.com>
Message-ID: <920c5d36-5637-1fba-034b-8ea3d41c131c@huawei.com>
Date:   Tue, 12 May 2020 11:00:53 +0100
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On 12/05/2020 10:35, Jason Yan wrote:
> 
> 
> 在 2020/5/12 16:23, John Garry 写道:
>> On 12/05/2020 07:33, Jason Yan wrote:
>>> The 'proc_name' entry in sysfs for hisi_sas is 'null' now becuase it is
>>> not initialized in scsi_host_template. It looks like:
>>>
>>> [root@localhost ~]# cat /sys/class/scsi_host/host2/proc_name
>>> (null)
>>>
>>
>> hmmm.. it would be good to tell us what this buys us, apart from the 
>> proc_name file.
>>
> 
> When there is more than one storage cards(or controllers) in the system, 
> I'm tring to find out which host is belong to which card. And then I 
> found this in scsi_host in sysfs but the output is '(null)' which is odd.

"dmesg | grep host" would give this info, like:

root@(none)$ dmesg | grep host0
[    8.877245] scsi host0: hisi_sas_v2_hw

> 
>> I mean, if we had the sht show_info method implemented, then it could 
>> be useful (which is even marked as obsolete now).
>>
> 
> I found this is interesting while in the sysfs filesystem we have a 
> procfs stuff in it.

It's only the name of the procfs entry, if it exists.

And, since .show_info is obsolete, I don't see why .proc_name is not 
also obsolete.

> I was planned to rename this entry to 'name' and use 
> the struct member 'name' directly in struct scsi_host_template. But this 
> may break userspace applications.
> 

Thanks,
John