Re: [PATCH v2 for-next 1/2] RDMA/hns: Add the workqueue framework for flush cqe handler

[Jason Gunthorpe <jgg@ziepe.ca>]

On Tue, Nov 19, 2019 at 04:00:00PM +0800, Liuyixian (Eason) wrote:
> 
> 
> On 2019/11/19 1:02, Jason Gunthorpe wrote:
> > On Mon, Nov 18, 2019 at 09:50:24PM +0800, Liuyixian (Eason) wrote:
> >>> It kind of looks like this can be called multiple times? It won't work
> >>> right unless it is called exactly once
> >>>
> >>> Jason
> >>
> >> Yes, you are right.
> >>
> >> So I think the reasonable solution is to allocate it dynamically, and I think
> >> it is a very very little chance that the allocation will be failed. If this happened,
> >> I think the application also needs to be over.
> > 
> > Why do you need more than one work in parallel for this? Once you
> > start to move the HW to error that only has to happen once, surely?
> > 
> > Jason
>
> The flush operation moves QP, not the HW to error.
> 
> For the QP, maybe the process A is posting send while the other
> process B is modifying qp to error, both of these two operation
> needs to initialize one flush work. That's why it could be called
> multiple times.

The work function does something that looks like it only has to happen
once per QP.

One do you need to keep re-queing this thing every time the user posts
a WR?

Jason