Tom Tucker wrote:
> Store the max payload supported by the transport in the switch
> instead of reaching into the socket since not all transports 
> (RDMA) have a socket.
> 
> Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
> Signed-off-by: Peter Leckie <pleckie@melbourne.sgi.com>
> Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
> ---
> 
>  include/linux/sunrpc/svcsock.h |    6 ++++++
>  net/sunrpc/svc.c               |    5 ++---
>  net/sunrpc/svcsock.c           |    2 ++
>  3 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
> index 3faa95c..4e24e6d 100644
> --- a/include/linux/sunrpc/svcsock.h
> +++ b/include/linux/sunrpc/svcsock.h
> @@ -35,6 +35,12 @@ struct svc_xprt {
>  	 * Return 1 if sufficient space to write reply to network.
>  	 */
>  	int			(*xpt_has_wspace)(struct svc_sock *);
> +	/*
> +	 * Stores the largest payload (i.e. READ, WRITE or READDIR
> +	 * data length not including NFS headers) supported by the
> +	 * svc_sock.
> +	 */
> +	u32			xpt_max_payload;
>  };

Only worth 2 cents, but perhaps you could make a separate section within 
svc_xprt for these variables, rather than mixing them with the xpt 
methods.  I think separating these is more traditional Linux style.

I notice that the type of the client's rpc_xprt->max_payload is size_t, 
which may be the wrong type -- u32 might be better.

>  /*
> diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
> index 72a900f..41f9ee0 100644
> --- a/net/sunrpc/svc.c
> +++ b/net/sunrpc/svc.c
> @@ -1036,10 +1036,9 @@ err_bad:
>   */
>  u32 svc_max_payload(const struct svc_rqst *rqstp)
>  {
> -	int max = RPCSVC_MAXPAYLOAD_TCP;
> +	struct svc_sock *svsk = rqstp->rq_sock;
> +	int max = svsk->sk_xprt->xpt_max_payload;
>  
> -	if (rqstp->rq_sock->sk_sock->type == SOCK_DGRAM)
> -		max = RPCSVC_MAXPAYLOAD_UDP;
>  	if (rqstp->rq_server->sv_max_payload < max)
>  		max = rqstp->rq_server->sv_max_payload;
>  	return max;
> diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
> index b16dad4..0dc94a8 100644
> --- a/net/sunrpc/svcsock.c
> +++ b/net/sunrpc/svcsock.c
> @@ -897,6 +897,7 @@ static const struct svc_xprt svc_udp_xpr
>  	.xpt_detach = svc_sock_detach,
>  	.xpt_free = svc_sock_free,
>  	.xpt_has_wspace = svc_udp_has_wspace,
> +	.xpt_max_payload = RPCSVC_MAXPAYLOAD_UDP,
>  };
>  
>  static void
> @@ -1368,6 +1369,7 @@ static const struct svc_xprt svc_tcp_xpr
>  	.xpt_free = svc_sock_free,
>  	.xpt_prep_reply_hdr = svc_tcp_prep_reply_hdr,
>  	.xpt_has_wspace = svc_tcp_has_wspace,
> +	.xpt_max_payload = RPCSVC_MAXPAYLOAD_TCP,
>  };
>  
>  static void