RDMA/rtrs: Enable the same selective signal for heartbeat and IO

On idle session, because we do not do signal for heartbeat, it will
overflow the send queue after sometime.

To avoid that, we need to enable the signal for heartbeat. To do that, add
a new member signal_interval in rtrs_path, which will set min of
queue_depth and SERVICE_CON_QUEUE_DEPTH, and track it for both heartbeat
and IO, so the sq queue full accounting is correct.

Fixes: b38041d5 ("RDMA/rtrs: Do not signal for heatbeat")
Link: https://lore.kernel.org/r/20210712060750.16494-4-jinpu.wang@ionos.comSigned-off-by: NJack Wang <jinpu.wang@ionos.com>
Reviewed-by: NAleksei Marov <aleksei.marov@ionos.com>
Reviewed-by: NGioh Kim <gi-oh.kim@ionos.com>
Reviewed-by: NMd Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/ulp/rtrs/rtrs-clt.c

@@ -478,7 +478,7 @@ static int rtrs_post_send_rdma(struct rtrs_clt_con *con,
 	 * From time to time we have to post signalled sends,
 	 * or send queue will fill up and only QP reset can help.
 	 */
-	flags = atomic_inc_return(&con->c.wr_cnt) % sess->queue_depth ?
+	flags = atomic_inc_return(&con->c.wr_cnt) % sess->s.signal_interval ?
 			0 : IB_SEND_SIGNALED;
 
 	ib_dma_sync_single_for_device(sess->s.dev->ib_dev, req->iu->dma_addr,
@@ -680,6 +680,7 @@ static void rtrs_clt_rdma_done(struct ib_cq *cq, struct ib_wc *wc)
 	case IB_WC_RDMA_WRITE:
 		/*
 		 * post_send() RDMA write completions of IO reqs (read/write)
+		 * and hb.
 		 */
 		break;
 
@@ -1043,7 +1044,7 @@ static int rtrs_post_rdma_write_sg(struct rtrs_clt_con *con,
 	 * From time to time we have to post signalled sends,
 	 * or send queue will fill up and only QP reset can help.
 	 */
-	flags = atomic_inc_return(&con->c.wr_cnt) % sess->queue_depth ?
+	flags = atomic_inc_return(&con->c.wr_cnt) % sess->s.signal_interval ?
 			0 : IB_SEND_SIGNALED;
 
 	ib_dma_sync_single_for_device(sess->s.dev->ib_dev, req->iu->dma_addr,
@@ -1849,6 +1850,8 @@ static int rtrs_rdma_conn_established(struct rtrs_clt_con *con,
 				return -ENOMEM;
 		}
 		sess->queue_depth = queue_depth;
+		sess->s.signal_interval = min_not_zero(queue_depth,
+						(unsigned short) SERVICE_CON_QUEUE_DEPTH);
 		sess->max_hdr_size = le32_to_cpu(msg->max_hdr_size);
 		sess->max_io_size = le32_to_cpu(msg->max_io_size);
 		sess->flags = le32_to_cpu(msg->flags);

drivers/infiniband/ulp/rtrs/rtrs-pri.h

@@ -109,6 +109,7 @@ struct rtrs_sess {
 	unsigned int		con_num;
 	unsigned int		irq_con_num;
 	unsigned int		recon_cnt;
+	unsigned int		signal_interval;
 	struct rtrs_ib_dev	*dev;
 	int			dev_ref;
 	struct ib_cqe		*hb_cqe;

drivers/infiniband/ulp/rtrs/rtrs-srv.c

@@ -201,7 +201,6 @@ static int rdma_write_sg(struct rtrs_srv_op *id)
 	struct rtrs_srv_sess *sess = to_srv_sess(s);
 	dma_addr_t dma_addr = sess->dma_addr[id->msg_id];
 	struct rtrs_srv_mr *srv_mr;
-	struct rtrs_srv *srv = sess->srv;
 	struct ib_send_wr inv_wr;
 	struct ib_rdma_wr imm_wr;
 	struct ib_rdma_wr *wr = NULL;
@@ -269,7 +268,7 @@ static int rdma_write_sg(struct rtrs_srv_op *id)
 	 * From time to time we have to post signaled sends,
 	 * or send queue will fill up and only QP reset can help.
 	 */
-	flags = (atomic_inc_return(&id->con->c.wr_cnt) % srv->queue_depth) ?
+	flags = (atomic_inc_return(&id->con->c.wr_cnt) % s->signal_interval) ?
 		0 : IB_SEND_SIGNALED;
 
 	if (need_inval) {
@@ -347,7 +346,6 @@ static int send_io_resp_imm(struct rtrs_srv_con *con, struct rtrs_srv_op *id,
 	struct ib_send_wr inv_wr, *wr = NULL;
 	struct ib_rdma_wr imm_wr;
 	struct ib_reg_wr rwr;
-	struct rtrs_srv *srv = sess->srv;
 	struct rtrs_srv_mr *srv_mr;
 	bool need_inval = false;
 	enum ib_send_flags flags;
@@ -396,7 +394,7 @@ static int send_io_resp_imm(struct rtrs_srv_con *con, struct rtrs_srv_op *id,
 	 * From time to time we have to post signalled sends,
 	 * or send queue will fill up and only QP reset can help.
 	 */
-	flags = (atomic_inc_return(&con->c.wr_cnt) % srv->queue_depth) ?
+	flags = (atomic_inc_return(&con->c.wr_cnt) % s->signal_interval) ?
 		0 : IB_SEND_SIGNALED;
 	imm = rtrs_to_io_rsp_imm(id->msg_id, errno, need_inval);
 	imm_wr.wr.next = NULL;
@@ -1268,8 +1266,9 @@ static void rtrs_srv_rdma_done(struct ib_cq *cq, struct ib_wc *wc)
 	case IB_WC_SEND:
 		/*
 		 * post_send() RDMA write completions of IO reqs (read/write)
+		 * and hb.
 		 */
-		atomic_add(srv->queue_depth, &con->sq_wr_avail);
+		atomic_add(s->signal_interval, &con->sq_wr_avail);
 
 		if (unlikely(!list_empty_careful(&con->rsp_wr_wait_list)))
 			rtrs_rdma_process_wr_wait_list(con);
@@ -1659,6 +1658,8 @@ static int create_con(struct rtrs_srv_sess *sess,
 		max_send_wr = min_t(int, wr_limit,
 				    SERVICE_CON_QUEUE_DEPTH * 2 + 2);
 		max_recv_wr = max_send_wr;
+		s->signal_interval = min_not_zero(srv->queue_depth,
+						  (size_t)SERVICE_CON_QUEUE_DEPTH);
 	} else {
 		/* when always_invlaidate enalbed, we need linv+rinv+mr+imm */
 		if (always_invalidate)

drivers/infiniband/ulp/rtrs/rtrs.c

@@ -187,10 +187,15 @@ int rtrs_post_rdma_write_imm_empty(struct rtrs_con *con, struct ib_cqe *cqe,
 				    struct ib_send_wr *head)
 {
 	struct ib_rdma_wr wr;
+	struct rtrs_sess *sess = con->sess;
+	enum ib_send_flags sflags;
+
+	sflags = (atomic_inc_return(&con->wr_cnt) % sess->signal_interval) ?
+		0 : IB_SEND_SIGNALED;
 
 	wr = (struct ib_rdma_wr) {
 		.wr.wr_cqe	= cqe,
-		.wr.send_flags	= flags,
+		.wr.send_flags	= sflags,
 		.wr.opcode	= IB_WR_RDMA_WRITE_WITH_IMM,
 		.wr.ex.imm_data	= cpu_to_be32(imm_data),
 	};