Re: [PATCH 0/5]stop normal completion path entering a timeout req

[jianchao.wang]

Hi Christoph

On 06/21/2018 04:19 PM, Christoph Hellwig wrote:
> On Thu, Jun 21, 2018 at 09:43:26AM +0800, jianchao.wang wrote:
>> So we have to preserve the ability of block layer that it could prevent
>> IO completion path from entering a timeout request.
>>
>> With scsi-debug module, I tried to simulate a scenario where timeout and IO
>> completion path could occur concurrently, the system ran into crash easily.
> 
> Trace, please.  With the latest kernel.  I'm not saying that there
> is nothing to fix, but the mode of never completing once timeout
> requests as currently done is SCSI is clearly broken.
> 

Sorry, I don't quite get your point.
Do you mean we should do the modification in the scsi layer ?
Actually, I used to look at the code to try to stop io completion on timeout request
in scsi-mid layer, but it looks like difficult, especially, scsi eh would try
to borrow the command to issue admin command such as get sense, test unit,etc.

Thanks
Jianchao