linux/net/sunrpc/xprtrdma/svc_rdma_backchannel.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2015-2018 Oracle.  All rights reserved.
 *
 * Support for reverse-direction RPCs on RPC/RDMA (server-side).
 */

#include <linux/sunrpc/svc_rdma.h>

#include "xprt_rdma.h"
#include <trace/events/rpcrdma.h>

/**
 * svc_rdma_handle_bc_reply - Process incoming backchannel Reply
 * @rqstp: resources for handling the Reply
 * @rctxt: Received message
 *
 */
void svc_rdma_handle_bc_reply(struct svc_rqst *rqstp,
			      struct svc_rdma_recv_ctxt *rctxt)
{ … }

/* Send a reverse-direction RPC Call.
 *
 * Caller holds the connection's mutex and has already marshaled
 * the RPC/RDMA request.
 *
 * This is similar to svc_rdma_send_reply_msg, but takes a struct
 * rpc_rqst instead, does not support chunks, and avoids blocking
 * memory allocation.
 *
 * XXX: There is still an opportunity to block in svc_rdma_send()
 * if there are no SQ entries to post the Send. This may occur if
 * the adapter has a small maximum SQ depth.
 */
static int svc_rdma_bc_sendto(struct svcxprt_rdma *rdma,
			      struct rpc_rqst *rqst,
			      struct svc_rdma_send_ctxt *sctxt)
{ … }

/* Server-side transport endpoint wants a whole page for its send
 * buffer. The client RPC code constructs the RPC header in this
 * buffer before it invokes ->send_request.
 */
static int
xprt_rdma_bc_allocate(struct rpc_task *task)
{ … }

static void
xprt_rdma_bc_free(struct rpc_task *task)
{ … }

static int
rpcrdma_bc_send_request(struct svcxprt_rdma *rdma, struct rpc_rqst *rqst)
{ … }

/**
 * xprt_rdma_bc_send_request - Send a reverse-direction Call
 * @rqst: rpc_rqst containing Call message to be sent
 *
 * Return values:
 *   %0 if the message was sent successfully
 *   %ENOTCONN if the message was not sent
 */
static int xprt_rdma_bc_send_request(struct rpc_rqst *rqst)
{ … }

static void
xprt_rdma_bc_close(struct rpc_xprt *xprt)
{ … }

static void
xprt_rdma_bc_put(struct rpc_xprt *xprt)
{ … }

static const struct rpc_xprt_ops xprt_rdma_bc_procs = …;

static const struct rpc_timeout xprt_rdma_bc_timeout = …;

/* It shouldn't matter if the number of backchannel session slots
 * doesn't match the number of RPC/RDMA credits. That just means
 * one or the other will have extra slots that aren't used.
 */
static struct rpc_xprt *
xprt_setup_rdma_bc(struct xprt_create *args)
{ … }

struct xprt_class xprt_rdma_bc = …;