APPLIED: [SRU][F:linux-bluefield][PATCH v3 0/1] UBUNTU: SAUCE: tmfifo: Fix a memory barrier issue

[Tim Gardner]

Applied to focal:bluefield/master-next. Thanks.

-rtg

On 5/6/21 6:30 AM, Liming Sun wrote:
> BugLink: https://bugs.launchpad.net/bugs/1927262
> 
> SRU Justification:
> 
> [Impact]
> 
> * The virtio framework uses wmb() when updating avail->idx. It guarantees
>    the write order, but not necessarily loading order for the code accessing
>    the memory. So potentially it could cause traffic stuck which has been
>    observed in the field.
> 
> [Fix]
> * This commit adds a load barrier after reading the avail->idx to make sure
>    all the data in the descriptor is visible. It also adds a barrier when
>    returning the packet to virtio framework to make sure read/writes are
>    visible to the virtio code.
> 
> [Test Case]
> * Just normal test. This change doesn't affect any functionality.
> 
> [Regression Potential]
> 
> * This version of the driver was tested by QA/verification for a while so no
>    known regression at the moment.
> 

-- 
-----------
Tim Gardner
Canonical, Inc