Re: [PATCH v1] RDMA/core: Fix check_flush_dependency splat on addr_wq

[Jason Gunthorpe <jgg@nvidia.com>]

On Fri, Aug 26, 2022 at 02:02:55PM +0000, Chuck Lever III wrote:
 
> I see recent commits that do exactly what I've done for the reason I've done it.
> 
> 4c4b1996b5db ("IB/hfi1: Fix WQ_MEM_RECLAIM warning")

No, this one says:

    The hfi1_wq does not allocate memory with GFP_KERNEL or otherwise become
    entangled with memory reclaim, so this flag is appropriate.
    
So it is OK, it is not the same thing as adding WQ_MEM_RECLAIM to a WQ
that allocates memory.

> I accept that this might be a long chain to pull, but we need a plan
> to resolve this. 

It is not just a long chain, it is something that was never designed
to even work or thought about. People put storage ULPs on top of this
and just ignored the problem.

If someone wants to tackle this then we need a comprehensive patch
series identifying what functions are safe to call under memory
reclaim contexts and then fully auditing them that they are actually
safe.

Right now I don't even know the basic information what functions the
storage community need to be reclaim safe.

Jason