Re: [PATCH] RDMA/rxe: Fix deadlock in rxe_do_local_ops()

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, May 23, 2022 at 05:32:52PM -0500, Bob Pearson wrote:
> When a local operation (invalidate mr, reg mr, bind mw) is finished
> there will be no ack packet coming from a responder to cause the
> wqe to be completed. This may happen anyway if a subsequent wqe
> performs IO. Currently if the wqe is signalled the completer
> tasklet is scheduled immediately but not otherwise.
> 
> This leads to a deadlock if the next wqe has the fence bit set in
> send flags and the operation is not signalled. This patch removes
> the condition that the wqe must be signalled in order to schedule
> the completer tasklet which is the simplest fix for this deadlock
> and is fairly low cost. This is the analog for local operations of
> always setting the ackreq bit in all last or only request packets
> even if the operation is not signalled.
> 
> Reported-by: Jenny Hack <jhack@hpe.com>
> Fixes: c1a411268a4b1 ("RDMA/rxe: Move local ops to subroutine")
> Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
> ---
>  drivers/infiniband/sw/rxe/rxe_req.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)

Applied to for-next, thanks

Jason