Re: [PATCH] SUNRPC: Fix backchannel reply, again

[Jeff Layton <jlayton@kernel.org>]

On Fri, 2024-06-14 at 10:18 -0400, cel@kernel.org wrote:
> From: Chuck Lever <chuck.lever@oracle.com>
> 
> I still see "RPC: Could not send backchannel reply error: -110"
> quite often, along with slow-running tests. Debugging shows that the
> backchannel is still stumbling when it has to queue a callback reply
> on a busy transport.
> 
> Note that every one of these timeouts causes a connection loss by
> virtue of the xprt_conditional_disconnect() call in that arm of
> call_cb_transmit_status().
> 
> I found that setting to_maxval is necessary to get the RPC timeout
> logic to behave whenever to_exponential is not set.
> 
> Fixes: 57331a59ac0d ("NFSv4.1: Use the nfs_client's rpc timeouts for
> backchannel")
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  net/sunrpc/svc.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
> index 965a27806bfd..f4ddb2961042 100644
> --- a/net/sunrpc/svc.c
> +++ b/net/sunrpc/svc.c
> @@ -1643,6 +1643,7 @@ void svc_process_bc(struct rpc_rqst *req,
> struct svc_rqst *rqstp)
>  		timeout.to_initval = req->rq_xprt->timeout-
> >to_initval;
>  		timeout.to_retries = req->rq_xprt->timeout-
> >to_retries;
>  	}
> +	timeout.to_maxval = timeout.to_initval;
>  	memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req-
> >rq_snd_buf));
>  	task = rpc_run_bc_task(req, &timeout);
>  

Reviewed-by: Jeff Layton <jlayton@kernel.org>