Re: [PATCH v2] block: don't allow multiple bios for IOCB_NOWAIT issue

[Jens Axboe <axboe@kernel.dk>]

On 1/24/23 9:03 AM, Michael Kelley (LINUX) wrote:
> From: Jens Axboe <axboe@kernel.dk> Sent: Saturday, January 21, 2023 1:11 PM
>>
>> On 1/20/23 9:56?PM, Michael Kelley (LINUX) wrote:
>>> From: Jens Axboe <axboe@kernel.dk> Sent: Monday, January 16, 2023 1:06 PM
> 
> [snip]
> 
>>>
>>> I've wrapped up my testing on this patch.  All testing was via
>>> io_uring -- I did not test other paths.  Testing was against a
>>> combination of this patch and the previous patch set for a similar
>>> problem. [1]
>>>
>>> I tested with a simple test program to issue single I/Os, and verified
>>> the expected paths were taken through the block layer and io_uring
>>> code for various size I/Os, including over 1 Mbyte.  No EAGAIN errors
>>> were seen. This testing was with a 6.1 kernel.
>>>
>>> Also tested the original app that surfaced the problem.  It's a larger
>>> scale workload using io_uring, and is where the problem was originally
>>> encountered.  That workload runs on a purpose-built 5.15 kernel, so I
>>> backported both patches to 5.15 for this testing.  All looks good. No
>>> EAGAIN errors were seen.
>>
>> Thanks a lot for your thorough testing! Can you share the 5.15
>> backports, so we can put them into 5.15-stable as well potentially?
>>
> 
> Certainly.  What's the best way to do that?  Should I send them to you,
> or to the linux-block list?  Or post directly to stable@vger.kernel.org?
> If the latter, maybe I need to wait until it has an upstream commit ID
> that can be referenced.  Also, you or someone should do a quick review
> of the backport to make sure I didn't break something in a path I
> didn't test.

Just send them to the block list, then we have them for when the commit
hits upstream and gives us a chance to review them upfront.

Thanks!

-- 
Jens Axboe