APPLIED: [SRU][Bionic][PATCH 0/2] Fix IO hang regression

[Seth Forshee]

On Sat, Apr 21, 2018 at 04:08:24PM -0500, Seth Forshee wrote:
> BugLink: http://bugs.launchpad.net/bugs/1765232
> 
> Impact: Since 4.15.0-15 some machines have been failing to boot due to
> IO hangs. This is caused by patches applied for LP #1759723, which
> assigned managed interrupt vectors and reply queues for all possible
> CPUs, not just present CPUs. Some drivers were not prepared to cope with
> this and end up selecting reply queues not mapped to an online CPU,
> causing IO hangs during boot.
> 
> Fix: There are driver fixes available upstream, but there are 8-ish
> patches in total and we're extremely close to release, so the safer bet
> it to just revert the patches for LP #1759723. We can consider
> reintroducing them with required fixes at a later time.
> 
> Regression Potential: This is obviously going to reintroduce the problem
> the patches were intended to fix. These are less serious than the
> problems which the patches introduced, and IBM has given their okay to
> revert them as well.
> 
> Test Case: Verified to fix affected hardware on LP #1765232.

Applied to bionic/master-next.