Backward direction RPC replies are sent via the client transport's
send_request method, the same way forward direction RPC calls are
sent.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/backchannel.c | 45 +++++++++++++++++++++++++++++++++++++
net/sunrpc/xprtrdma/rpc_rdma.c | 5 ++++
net/sunrpc/xprtrdma/xprt_rdma.h | 1 +
3 files changed, 51 insertions(+)
diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c
index f5c7122..cc9c762 100644
--- a/net/sunrpc/xprtrdma/backchannel.c
+++ b/net/sunrpc/xprtrdma/backchannel.c
@@ -168,6 +168,51 @@ out_err:
}
/**
+ * rpcrdma_bc_marshal_reply - Send backwards direction reply
+ * @rqst: buffer containing RPC reply data
+ *
+ * Returns zero on success.
+ */
+int rpcrdma_bc_marshal_reply(struct rpc_rqst *rqst)
+{
+ struct rpc_xprt *xprt = rqst->rq_xprt;
+ struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
+ struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
+ struct rpcrdma_msg *headerp;
+ size_t rpclen;
+
+ headerp = rdmab_to_msg(req->rl_rdmabuf);
+ headerp->rm_xid = rqst->rq_xid;
+ headerp->rm_vers = rpcrdma_version;
+ headerp->rm_credit =
+ cpu_to_be32(r_xprt->rx_buf.rb_bc_srv_max_requests);
+ headerp->rm_type = rdma_msg;
+ headerp->rm_body.rm_chunks[0] = xdr_zero;
+ headerp->rm_body.rm_chunks[1] = xdr_zero;
+ headerp->rm_body.rm_chunks[2] = xdr_zero;
+
+ rpclen = rqst->rq_svec[0].iov_len;
+
+ pr_info("RPC: %s: rpclen %zd headerp 0x%p lkey 0x%x\n",
+ __func__, rpclen, headerp, rdmab_lkey(req->rl_rdmabuf));
+ pr_info("RPC: %s: RPC/RDMA: %*ph\n",
+ __func__, (int)RPCRDMA_HDRLEN_MIN, headerp);
+ pr_info("RPC: %s: RPC: %*ph\n",
+ __func__, (int)rpclen, rqst->rq_svec[0].iov_base);
+
+ req->rl_send_iov[0].addr = rdmab_addr(req->rl_rdmabuf);
+ req->rl_send_iov[0].length = RPCRDMA_HDRLEN_MIN;
+ req->rl_send_iov[0].lkey = rdmab_lkey(req->rl_rdmabuf);
+
+ req->rl_send_iov[1].addr = rdmab_addr(req->rl_sendbuf);
+ req->rl_send_iov[1].length = rpclen;
+ req->rl_send_iov[1].lkey = rdmab_lkey(req->rl_sendbuf);
+
+ req->rl_niovs = 2;
+ return 0;
+}
+
+/**
* xprt_rdma_bc_destroy - Release resources for handling backchannel requests
* @xprt: transport associated with these backchannel resources
* @reqs: number of incoming requests to destroy; ignored
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 287c874..d0dbbf7 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -441,6 +441,11 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
enum rpcrdma_chunktype rtype, wtype;
struct rpcrdma_msg *headerp;
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+ if (test_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state))
+ return rpcrdma_bc_marshal_reply(rqst);
+#endif
+
/*
* rpclen gets amount of data in first buffer, which is the
* pre-registered buffer.
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 37d0d7f..a59ce18 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -516,6 +516,7 @@ void xprt_rdma_cleanup(void);
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
+int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
--
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