linux-kernel - Re: [PATCH] libata: add horkage for M88V29

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Message-ID: <43061e32-3a00-d8a1-5946-656d38ff195c@gmail.com>
Date:   Thu, 23 Jun 2022 12:12:02 +0200
From:   Böszörményi Zoltán <zboszor@...il.com>
To:     Damien Le Moal <damien.lemoal@...nsource.wdc.com>, zboszor@...hu,
        linux-kernel@...r.kernel.org, linux-ide@...r.kernel.org
Subject: Re: [PATCH] libata: add horkage for M88V29

2022. 06. 23. 11:32 keltezéssel, Böszörményi Zoltán írta:
> 2022. 06. 23. 10:46 keltezéssel, Damien Le Moal írta:
>> On 6/23/22 17:38, Böszörményi Zoltán wrote:
>>> 2022. 06. 23. 10:22 keltezéssel, Damien Le Moal írta:
>>>> On 6/23/22 16:47, Böszörményi Zoltán wrote:
>>>>> 2022. 02. 08. 9:07 keltezéssel, Damien Le Moal írta:
>>>>>> On 2/4/22 21:57, zboszor@...hu wrote:
>>>>>>> From: Zoltán Böszörményi <zboszor@...il.com>
>>>>>>>
>>>>>>> This device is a CF card, or possibly an SSD in CF form factor.
>>>>>>> It supports NCQ and high speed DMA.
>>>>>>>
>>>>>>> While it also advertises TRIM support, I/O errors are reported
>>>>>>> when the discard mount option fstrim is used. TRIM also fails
>>>>>>> when disabling NCQ and not just as an NCQ command.
>>>>>>>
>>>>>>> TRIM must be disabled for this device.
>>>>>>>
>>>>>>> Signed-off-by: Zoltán Böszörményi <zboszor@...il.com>
>>>>>>> ---
>>>>>>>     drivers/ata/libata-core.c | 1 +
>>>>>>>     1 file changed, 1 insertion(+)
>>>>>>>
>>>>>>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
>>>>>>> index 67f88027680a..4a7f58fcc411 100644
>>>>>>> --- a/drivers/ata/libata-core.c
>>>>>>> +++ b/drivers/ata/libata-core.c
>>>>>>> @@ -4028,6 +4028,7 @@ static const struct ata_blacklist_entry ata_device_blacklist 
>>>>>>> [] = {
>>>>>>>             /* devices that don't properly handle TRIM commands */
>>>>>>>         { "SuperSSpeed S238*",        NULL, ATA_HORKAGE_NOTRIM, },
>>>>>>> +    { "M88V29*",            NULL, ATA_HORKAGE_NOTRIM, },
>>>>>>>             /*
>>>>>>>          * As defined, the DRAT (Deterministic Read After Trim) and RZAT
>>>>>> Applied to for-5.17-fixes. Thanks !
>>>>> Thank you. However, I have second thoughts about this patch.
>>>>> The device advertises this:
>>>>>
>>>>> # hdparm -iI /dev/sda
>>>>> ...
>>>>>     Enabled Supported
>>>>>        *    Data Set Management TRIM supported (limit 1 block)
>>>>> ...
>>>>>
>>>>> but the I/O failures always reported higher number of blocks,
>>>>> IIRC the attempted number of block was 8 or so.
>>>>>
>>>>> Can the kernel limit or split TRIM commands according to the
>>>>> advertised limit? If not (or not yet) then the quirk is good for now.
>>>> Yes, the kernel does that. See the sysfs queue attributes
>>>> discard_max_bytes and discard_max_hw_bytes. What are the values for your
>>>> device ? I think that the "limit 1 block" indicated by hdparm is simply to
>>>> say that the DSM command (to trim the device) accept only at most a 1
>>>> block (512 B) list of sectors to trim. That is not the actual trim limit
>>>> for each sector range in that list.
>>> With the quirk in effect (TRIM disabled) I have these:
>>>
>>> [root@...f queue]# pwd
>>> /sys/block/sda/queue
>>> [root@...f queue]# cat discard_granularity
>>> 0
>>> [root@...f queue]# cat discard_max_bytes
>>> 0
>>> [root@...f queue]# cat discard_max_hw_bytes
>>> 0
>> Yes, expected. What are the values without the quirk applied ?
>
> I built 5.18.6 with removing the quirk.
>
> [root@...f queue]# pwd
> /sys/block/sda/queue/
> [root@...f queue]# cat discard_granularity
> 512
> [root@...f queue]# cat discard_max_bytes
> 2147450880
> [root@...f queue]# cat discard_max_hw_bytes
> 2147450880
> [root@...f queue]# cat max_discard_segments
> 1

"echo 512 >discard_max_hw_bytes" says permission denied.
"echo 512 >discard_max_bytes" can be set

But with or without libata.force=noncqtrim, running
"fstrim /boot" (which is ext4) goes into an infinite loop
dumping a lot of I/O errors into dmesg.

Interestingly, after setting discard_max_bytes=512,
in both cases (with or without libata.force=noncqrtim)
running "fstrim /" (which is f2fs) there is no error in
dmesg and fstrim returns after a small delay.

So I guess TRIM does work but ext4 seems to be misbehaving.

FWIW "mount" shows "discard" for the big f2fs partition but
it doesn't for ext4 but it's in the default mount option AFAIK.
"mount /boot -o remount.discard" doesn't make a difference.
the machine dumps a lot of errors into dmesg with "fstrim /boot".

>
>> With 5.19, you can use libata.force to disable/enable it. See
>> Documentation/admin-guide/kernel-parameters.txt for details.
>> You could try disabling DSM TRIM (queued trim) and see if the non-ncq trim
>> work.
>>
>