Re: [PATCH 12/15] RPC/RDMA: correct a 5 second pause on reconnecting to an idle server.

[Trond Myklebust <trond.myklebust@fys.uio.no>]

On Wed, 2008-10-08 at 11:48 -0400, Tom Talpey wrote:
> The RPC/RDMA code always performed a reconnect-with-backoff, even
> when re-establishing a connection to a server after the RPC layer
> closed it due to being idle.
> ---
> 
>  net/sunrpc/xprtrdma/transport.c |    5 +++--
>  net/sunrpc/xprtrdma/verbs.c     |    2 +-
>  2 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
> index c7d2380..278a544 100644
> --- a/net/sunrpc/xprtrdma/transport.c
> +++ b/net/sunrpc/xprtrdma/transport.c
> @@ -486,8 +486,9 @@ xprt_rdma_connect(struct rpc_task *task)
>  	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
>  
>  	if (!xprt_test_and_set_connecting(xprt)) {
> -		if (r_xprt->rx_ep.rep_connected != 0) {
> -			/* Reconnect */
> +		if (r_xprt->rx_ep.rep_connected &&
> +		    r_xprt->rx_ep.rep_connected != -EPIPE) {
> +			/* Reconnect with backoff */
>  			schedule_delayed_work(&r_xprt->rdma_connect,
>  				xprt->reestablish_timeout);
>  		} else {
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index a63d0c0..9ef7e0d 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -317,7 +317,7 @@ rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
>  		connstate = -ECONNREFUSED;
>  		goto connected;
>  	case RDMA_CM_EVENT_DISCONNECTED:
> -		connstate = -ECONNABORTED;
> +		connstate = -EPIPE;
>  		goto connected;
>  	case RDMA_CM_EVENT_DEVICE_REMOVAL:
>  		connstate = -ENODEV;

Hmm... Why not rather do the same as the socket code: have the
disconnect handler paths that don't require exponential backoff just
reset xprt->reestablish_timeout to 0?

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