Re: [PATCH] s390/vfio-ap: do not use open locks during VFIO_GROUP_NOTIFY_SET_KVM notification

[Tony Krowiak]

On 7/5/21 10:13 AM, Jason Gunthorpe wrote:
> On Thu, Jul 01, 2021 at 10:28:52AM -0400, Tony Krowiak wrote:
>
> > > I think Jason was talking about open coding locks in general.
> > That may be so, but his comments were in support of his
> > statement that the  mutex + wait_queue did not resolve
> > the issue reported vai the lockdep splat because it turned
> > off lockdep.
> Rgiht, if this used to be proper locks and lockdep complained then
> whatever potential deadlock it found is not magically removed by going
> to a wait_queue. It just removes the lockdep annotations that would
> identify the issue early.
>
> This is why people should not open code locks, it completely defeats
> lockdep. That alone is merit enough for this patch.

When you use the phrase "open code locks", to what are you
specifically referring? I am confused by the use of the phrase
"open code" in this context because open coding, at least as
I understand it, has to do with data analysis.

> Jason