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Subject: Re: [PATCH] drivers/ata: print trim features at device initialization
From:   Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
To:     "Martin K. Petersen" <martin.petersen@oracle.com>,
        Christoph Hellwig <hch@infradead.org>
Cc:     Jens Axboe <axboe@kernel.dk>, linux-ide@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
References: <155989287898.1506.14253954112551051148.stgit@buzz>
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 <eebfb1cc-f6d0-580e-1d56-2af0f481a92f@yandex-team.ru>
Message-ID: <048ed77f-8faa-fb67-c6bc-10d953f52f89@yandex-team.ru>
Date:   Sat, 8 Jun 2019 17:13:31 +0300
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On 08.06.2019 12:12, Konstantin Khlebnikov wrote:
> On 07.06.2019 19:58, Martin K. Petersen wrote:
>>
>> Konstantin,
>>
>>> +            if (dev->horkage & ATA_HORKAGE_NOTRIM)
>>> +                trim_status = "backlisted";
>>
>> blacklisted
> 
> Oops. My bad.
> 
>>
>>> +            else
>>> +                trim_status = "supported";
>>> +
>>> +            if (!ata_fpdma_dsm_supported(dev))
>>> +                trim_queued = "no";
>>> +            else if (dev->horkage & ATA_HORKAGE_NO_NCQ_TRIM)
>>> +                trim_queued = "backlisted";
>>
>> ditto
>>
>>> +            else
>>> +                trim_queued = "yes";
>>
>> Why is trim_status "supported" and trim_queued/trim_zero "yes"?
> 
> Hmm. This seems properties of trim, not independent features.
> 
>>
>>> +
>>> +            if (!ata_id_has_zero_after_trim(id))
>>> +                trim_zero = "no";
>>> +            else if (dev->horkage & ATA_HORKAGE_ZERO_AFTER_TRIM)
>>> +                trim_zero = "yes";
>>> +            else
>>> +                trim_zero = "maybe";
>>> +
>>> +            ata_dev_info(dev, "trim: %s, queued: %s, zero_after_trim: %s\n",
>>> +                     trim_status, trim_queued, trim_zero);
>>> +        }
>>> +
>>
>> Otherwise no particular objections. We were trying to limit noise during
>> boot which is why this information originally went to sysfs instead of
>> being printed during probe.
>>
> 
> On 08.06.2019 11:25, Christoph Hellwig wrote:> On Fri, Jun 07, 2019 at 10:34:39AM +0300, Konstantin Khlebnikov wrote:
>  >
>  > Do we really need to spam dmesg with even more ATA crap?  What about
>  > a sysfs file that can be read on demand instead?
>  >
> 
> Makes sense.
> 
> Trim state is exposed for ata_device: /sys/class/ata_device/devX.Y/trim
> but there is no link from scsi device to ata device so they hard to match.
> 
> I'll think about it.

Nope. There is no obvious way to link scsi device with ata_device.
ata_device is built on top of "transport_class" and "attribute_container".
This some extremely over engineered sysfs framework used only in ata/scsi.
I don't want to touch this.