Commit 82011c80 authored by Chuck Lever's avatar Chuck Lever
Browse files

SUNRPC: Move svc_xprt_received() call sites 



Currently, XPT_BUSY is not cleared until xpo_recvfrom returns.
That effectively blocks the receipt and handling of the next RPC
message until the current one has been taken off the transport.
This strict ordering is a requirement for socket transports.

For our kernel RPC/RDMA transport implementation, however, dequeuing
an ingress message is nothing more than a list_del(). The transport
can safely be marked un-busy as soon as that is done.

To keep the changes simpler, this patch just moves the
svc_xprt_received() call site from svc_handle_xprt() into the
transports, so that the actual optimization can be done in a
subsequent patch.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 7dcfbd86

net/sunrpc/svc_xprt.c

+4 −3
Original line number Diff line number Diff line
@@ -820,8 +820,10 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt) 
			newxpt->xpt_cred = get_cred(xprt->xpt_cred);

			svc_add_new_temp_xprt(serv, newxpt);

			trace_svc_xprt_accept(newxpt, serv->sv_name);

		} else

		} else {

			module_put(xprt->xpt_class->xcl_owner);

		}

		svc_xprt_received(xprt);

	} else if (svc_xprt_reserve_slot(rqstp, xprt)) {

		/* XPT_DATA|XPT_DEFERRED case: */

		dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
@@ -836,8 +838,6 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt) 
		rqstp->rq_reserved = serv->sv_max_mesg;

		atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);

	}

	/* clear XPT_BUSY: */

	svc_xprt_received(xprt);

out:

	trace_svc_handle_xprt(xprt, len);

	return len;
@@ -1248,6 +1248,7 @@ static noinline int svc_deferred_recv(struct svc_rqst *rqstp) 
	rqstp->rq_xprt_hlen   = dr->xprt_hlen;

	rqstp->rq_daddr       = dr->daddr;

	rqstp->rq_respages    = rqstp->rq_pages;

	svc_xprt_received(rqstp->rq_xprt);

	return (dr->argslen<<2) - dr->xprt_hlen;

}

net/sunrpc/svcsock.c

+7 −2
Original line number Diff line number Diff line
@@ -519,6 +519,7 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp) 
	if (serv->sv_stats)

		serv->sv_stats->netudpcnt++;



	svc_xprt_received(rqstp->rq_xprt);

	return len;



out_recv_err:
@@ -527,7 +528,7 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp) 
		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);

	}

	trace_svcsock_udp_recv_err(&svsk->sk_xprt, err);

	return 0;

	goto out_clear_busy;

out_cmsg_err:

	net_warn_ratelimited("svc: received unknown control message %d/%d; dropping RPC reply datagram\n",

			     cmh->cmsg_level, cmh->cmsg_type);
@@ -536,6 +537,8 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp) 
	local_bh_enable();

out_free:

	kfree_skb(skb);

out_clear_busy:

	svc_xprt_received(rqstp->rq_xprt);

	return 0;

}
@@ -1033,6 +1036,7 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp) 
	if (serv->sv_stats)

		serv->sv_stats->nettcpcnt++;



	svc_xprt_received(rqstp->rq_xprt);

	return rqstp->rq_arg.len;



err_incomplete:
@@ -1050,13 +1054,14 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp) 
	if (len != -EAGAIN)

		goto err_delete;

	trace_svcsock_tcp_recv_eagain(&svsk->sk_xprt, 0);

	return 0;

	goto err_noclose;

err_nuts:

	svsk->sk_datalen = 0;

err_delete:

	trace_svcsock_tcp_recv_err(&svsk->sk_xprt, len);

	svc_xprt_deferred_close(&svsk->sk_xprt);

err_noclose:

	svc_xprt_received(rqstp->rq_xprt);

	return 0;	/* record not complete */

}

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c

+6 −0
Original line number Diff line number Diff line
@@ -846,6 +846,7 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp) 
		/* No new incoming requests, terminate the loop */

		clear_bit(XPT_DATA, &xprt->xpt_flags);

		spin_unlock(&rdma_xprt->sc_rq_dto_lock);

		svc_xprt_received(xprt);

		return 0;

	}

	list_del(&ctxt->rc_list);
@@ -883,28 +884,33 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp) 
	rqstp->rq_xprt_ctxt = ctxt;

	rqstp->rq_prot = IPPROTO_MAX;

	svc_xprt_copy_addrs(rqstp, xprt);

	svc_xprt_received(xprt);

	return rqstp->rq_arg.len;



out_readlist:

	ret = svc_rdma_process_read_list(rdma_xprt, rqstp, ctxt);

	if (ret < 0)

		goto out_readfail;

	svc_xprt_received(xprt);

	return 0;



out_err:

	svc_rdma_send_error(rdma_xprt, ctxt, ret);

	svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);

	svc_xprt_received(xprt);

	return 0;



out_readfail:

	if (ret == -EINVAL)

		svc_rdma_send_error(rdma_xprt, ctxt, ret);

	svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);

	svc_xprt_received(xprt);

	return ret;



out_backchannel:

	svc_rdma_handle_bc_reply(rqstp, ctxt);

out_drop:

	svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);

	svc_xprt_received(xprt);

	return 0;

}