svcrdma: Use new CQ API for RPC-over-RDMA server send CQs

Calling ib_poll_cq() to sort through WCs during a completion is a
common pattern amongst RDMA consumers. Since commit 14d3a3b2498e
("IB: add a proper completion queue abstraction"), WC sorting can
be handled by the IB core.

By converting to this new API, svcrdma is made a better neighbor to
other RDMA consumers, as it allows the core to schedule the delivery
of completions more fairly amongst all active consumers.

This new API also aims each completion at a function that is
specific to the WR's opcode. Thus the ctxt->wr_op field and the
switch in process_context is replaced by a set of methods that
handle each completion type.

Because each ib_cqe carries a pointer to a completion method, the
core can now post operations on a consumer's QP, and handle the
completions itself.

The server's rdma_stat_sq_poll and rdma_stat_sq_prod metrics are no
longer updated.

As a clean up, the cq_event_handler, the dto_tasklet, and all
associated locking is removed, as they are no longer referenced or
used.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index a26ca569f257..4f1b1c4f45f9 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -297,8 +297,8 @@ static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
 
 	/* Prepare WRITE WR */
 	memset(&write_wr, 0, sizeof write_wr);
-	ctxt->wr_op = IB_WR_RDMA_WRITE;
-	write_wr.wr.wr_id = (unsigned long)ctxt;
+	ctxt->cqe.done = svc_rdma_wc_write;
+	write_wr.wr.wr_cqe = &ctxt->cqe;
 	write_wr.wr.sg_list = &sge[0];
 	write_wr.wr.num_sge = sge_no;
 	write_wr.wr.opcode = IB_WR_RDMA_WRITE;
@@ -549,8 +549,8 @@ static int send_reply(struct svcxprt_rdma *rdma,
 		goto err;
 	}
 	memset(&send_wr, 0, sizeof send_wr);
-	ctxt->wr_op = IB_WR_SEND;
-	send_wr.wr_id = (unsigned long)ctxt;
+	ctxt->cqe.done = svc_rdma_wc_send;
+	send_wr.wr_cqe = &ctxt->cqe;
 	send_wr.sg_list = ctxt->sge;
 	send_wr.num_sge = sge_no;
 	send_wr.opcode = IB_WR_SEND;
@@ -698,8 +698,8 @@ void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
 
 	/* Prepare SEND WR */
 	memset(&err_wr, 0, sizeof(err_wr));
-	ctxt->wr_op = IB_WR_SEND;
-	err_wr.wr_id = (unsigned long)ctxt;
+	ctxt->cqe.done = svc_rdma_wc_send;
+	err_wr.wr_cqe = &ctxt->cqe;
 	err_wr.sg_list = ctxt->sge;
 	err_wr.num_sge = 1;
 	err_wr.opcode = IB_WR_SEND;