reply: reply: [RFC PATCH v3 00/19] scsi: scsi_error: Introduce new error handle mechanism

reply: reply: [RFC PATCH v3 00/19] scsi: scsi_error: Introduce new error handle mechanism

[Jiangjianjun]

On 31/03/2025 04:10, Jiangjianjun wrote:
> Sorry for late message! I'm working on fixing and testing these issues before re-emailing.

What are you actually working on?

It seems that Hannes' "scsi: EH rework, main part" series and maybe this one can help resolve this following issue:

https://lore.kernel.org/linux-block/eef1e927-c9b2-c61d-7f48-92e65d8b0418@huawei.com/

with fix attempted in:

https://lore.kernel.org/linux-ide/20241031140731.224589-4-cassel@kernel.org/

so that we don't see "fixes" like:
https://lore.kernel.org/linux-scsi/20250329073236.2300582-1-liyihang9@huawei.com/T/#m80bcb3f57fd176b7ce41b1f26e8560de6ad52c9d

> 
> -----邮件原件-----
> 发件人: Christoph Hellwig <hch@infradead.org>
> 发送时间: 2025年3月20日 14:06
> 收件人: Hannes Reinecke <hare@suse.de>
> 抄送: Jiangjianjun <jiangjianjun3@huawei.com>; jejb@linux.ibm.com; 
> martin.petersen@oracle.com; linux-scsi@vger.kernel.org; 
> linux-kernel@vger.kernel.org; lixiaokeng <lixiaokeng@huawei.com>; 
> hewenliang (C) <hewenliang4@huawei.com>; Yangkunlin(Poincare) 
> <yangkunlin7@huawei.com>
> 主题: Re: [RFC PATCH v3 00/19] scsi: scsi_error: Introduce new error 
> handle mechanism
> 
> On Fri, Mar 14, 2025 at 10:01:40AM +0100, Hannes Reinecke wrote:
>> 3. The current EH framework is designed around 'struct scsi_cmnd'.
>> Which means that the command _initiating_ the error handling can only 
>> be returned once the _entire_ error handling (with all
>> escalations) is finished. And more often than not, the application is 
>> waiting on that command to be completed before the next I/O is sent.
>> And that really limits the effectiveness of any improved error 
>> handler; the application ultimatively has to wait for a host reset 
>> before it can contine.
> 
> And someone needs to get your old series to fix that merged before we even start talking about any major EH change.
> 

Sorry, the previous engineer Wen Chao's work has changed. Now I will continue to complete this work. In the future.
I will analyze the details of the solution, improve and refine the above suggestions, and carefully submit the email.

Re: reply: reply: [RFC PATCH v3 00/19] scsi: scsi_error: Introduce new error handle mechanism

[John Garry]

On 01/04/2025 04:32, Jiangjianjun wrote:

Please use standard mailing practice of inlining response.

> On 31/03/2025 04:10, Jiangjianjun wrote:
>> Sorry for late message! I'm working on fixing and testing these issues before re-emailing.
> What are you actually working on?
> 
> It seems that Hannes' "scsi: EH rework, main part" series and maybe this one can help resolve this following issue:
> 
> https://urldefense.com/v3/__https://lore.kernel.org/linux-block/ 
> eef1e927-c9b2-c61d-7f48-92e65d8b0418@huawei.com/__;!!ACWV5N9M2RV99hQ! 
> OO5I73jOVLARfumNZnn0L_cNWCWVmFHmNuzz74pUu12bSxsb7F1wQFuTJBCzEBZrdDE8cqBRf8e_Ddc4AmrbBgdRq9I$ 
> 
> with fix attempted in:
> 
> https://urldefense.com/v3/__https://lore.kernel.org/linux- 
> ide/20241031140731.224589-4-cassel@kernel.org/__;!!ACWV5N9M2RV99hQ! 
> OO5I73jOVLARfumNZnn0L_cNWCWVmFHmNuzz74pUu12bSxsb7F1wQFuTJBCzEBZrdDE8cqBRf8e_Ddc4AmrbVJtRc_g$ 
> 
> so that we don't see "fixes" like:
> https://urldefense.com/v3/__https://lore.kernel.org/linux- 
> scsi/20250329073236.2300582-1-liyihang9@huawei.com/T/ 
> *m80bcb3f57fd176b7ce41b1f26e8560de6ad52c9d__;Iw!!ACWV5N9M2RV99hQ! 
> OO5I73jOVLARfumNZnn0L_cNWCWVmFHmNuzz74pUu12bSxsb7F1wQFuTJBCzEBZrdDE8cqBRf8e_Ddc4AmrbNUtxBIA$ 
> 
>> -----邮件原件-----
>> 发件人: Christoph Hellwig<hch@infradead.org>
>> 发送时间: 2025年3月20日 14:06
>> 收件人: Hannes Reinecke<hare@suse.de>
>> 抄送: Jiangjianjun<jiangjianjun3@huawei.com>;jejb@linux.ibm.com;
>> martin.petersen@oracle.com;linux-scsi@vger.kernel.org;
>> linux-kernel@vger.kernel.org; lixiaokeng<lixiaokeng@huawei.com>;
>> hewenliang (C)<hewenliang4@huawei.com>; Yangkunlin(Poincare)
>> <yangkunlin7@huawei.com>
>> 主题: Re: [RFC PATCH v3 00/19] scsi: scsi_error: Introduce new error
>> handle mechanism
>>
>> On Fri, Mar 14, 2025 at 10:01:40AM +0100, Hannes Reinecke wrote:
>>> 3. The current EH framework is designed around 'struct scsi_cmnd'.
>>> Which means that the command_initiating_ the error handling can only
>>> be returned once the_entire_ error handling (with all
>>> escalations) is finished. And more often than not, the application is
>>> waiting on that command to be completed before the next I/O is sent.
>>> And that really limits the effectiveness of any improved error
>>> handler; the application ultimatively has to wait for a host reset
>>> before it can contine.
>> And someone needs to get your old series to fix that merged before we even start talking about any major EH change.
>>
> Sorry, the previous engineer Wen Chao's work has changed. Now I will continue to complete this work. In the future.
> I will analyze the details of the solution, improve and refine the above suggestions, and carefully submit the email.

JFYI, IIRC, that "scsi: EH rework, main part" or one of the prep series 
may require some form of SCSI reserved command support. Niklas raised 
that point here:
https://lore.kernel.org/linux-scsi/Zyo-E1PCvx_XULvg@ryzen/

I also remember commenting on this, but cannot find a reference.

The SCSI reserved commands series includes the following attempts:
https://lore.kernel.org/linux-scsi/20211125151048.103910-1-hare@suse.de/
https://lore.kernel.org/linux-scsi/1666693096-180008-1-git-send-email-john.garry@huawei.com/

Maybe to move format we can implement a basic solution for the concerned 
drivers, so that progress can be made.