[PATCH rdma-next 10/10] RDMA/mana_ib: Drain kernel receive and send queues

[Konstantin Taranov <kotaranov@linux.microsoft.com>]

From: Konstantin Taranov <kotaranov@microsoft.com>

Implement the core drain callbacks by moving the QP to ERR, posting a
completion-bearing marker, and waiting until that marker is flushed.

Signed-off-by: Konstantin Taranov <kotaranov@microsoft.com>
---
 drivers/infiniband/hw/mana/device.c  |  2 +
 drivers/infiniband/hw/mana/mana_ib.h |  2 +
 drivers/infiniband/hw/mana/qp.c      | 91 ++++++++++++++++++++++++++++
 3 files changed, 95 insertions(+)

diff --git a/drivers/infiniband/hw/mana/device.c b/drivers/infiniband/hw/mana/device.c
index cdaada7f6e8a..07c7fe678ff7 100644
--- a/drivers/infiniband/hw/mana/device.c
+++ b/drivers/infiniband/hw/mana/device.c
@@ -38,6 +38,8 @@ static const struct ib_device_ops mana_ib_dev_ops = {
 	.destroy_rwq_ind_table = mana_ib_destroy_rwq_ind_table,
 	.destroy_wq = mana_ib_destroy_wq,
 	.disassociate_ucontext = mana_ib_disassociate_ucontext,
+	.drain_rq = mana_ib_drain_rq,
+	.drain_sq = mana_ib_drain_sq,
 	.get_dma_mr = mana_ib_get_dma_mr,
 	.get_link_layer = mana_ib_get_link_layer,
 	.get_port_immutable = mana_ib_get_port_immutable,
diff --git a/drivers/infiniband/hw/mana/mana_ib.h b/drivers/infiniband/hw/mana/mana_ib.h
index 406b85abdef2..6eb06a1036ab 100644
--- a/drivers/infiniband/hw/mana/mana_ib.h
+++ b/drivers/infiniband/hw/mana/mana_ib.h
@@ -1059,6 +1059,8 @@ int mana_ib_post_recv(struct ib_qp *ibqp, const struct ib_recv_wr *wr,
 int mana_ib_post_send(struct ib_qp *ibqp, const struct ib_send_wr *wr,
 		      const struct ib_send_wr **bad_wr);
 
+void mana_ib_drain_sq(struct ib_qp *ibqp);
+void mana_ib_drain_rq(struct ib_qp *ibqp);
 void mana_drain_gsi_sqs(struct mana_ib_dev *mdev);
 int mana_ib_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc);
 int mana_ib_arm_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags flags);
diff --git a/drivers/infiniband/hw/mana/qp.c b/drivers/infiniband/hw/mana/qp.c
index ed6dbd66bd36..95374896ea82 100644
--- a/drivers/infiniband/hw/mana/qp.c
+++ b/drivers/infiniband/hw/mana/qp.c
@@ -1331,3 +1331,94 @@ int mana_ib_destroy_qp(struct ib_qp *ibqp, struct ib_udata *udata)
 
 	return -ENOENT;
 }
+
+struct mana_ib_drain_cqe {
+	struct ib_cqe cqe;
+	struct completion done;
+};
+
+static void mana_ib_drain_qp_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct mana_ib_drain_cqe *cqe = container_of(wc->wr_cqe,
+						     struct mana_ib_drain_cqe,
+						     cqe);
+	complete(&cqe->done);
+}
+
+void mana_ib_drain_sq(struct ib_qp *ibqp)
+{
+	struct ib_qp_attr attr = { .qp_state = IB_QPS_ERR };
+	struct mana_ib_drain_cqe sdrain;
+	struct ib_rdma_wr swr = {
+		.wr = {
+			.next = NULL,
+			.wr_cqe = &sdrain.cqe,
+			.opcode = IB_WR_SEND,
+		},
+	};
+	const struct ib_send_wr *bad_swr;
+	struct ib_cq *cq = ibqp->send_cq;
+	int ret;
+
+	ret = ib_modify_qp(ibqp, &attr, IB_QP_STATE);
+	if (ret) {
+		ibdev_err(ibqp->device, "Failed to drain SQ: modify QP returned %d\n", ret);
+		return;
+	}
+
+	sdrain.cqe.done = mana_ib_drain_qp_done;
+	init_completion(&sdrain.done);
+
+	ret = ib_post_send(ibqp, &swr.wr, &bad_swr);
+	if (ret) {
+		ibdev_err(ibqp->device, "Failed to post SQ drain WR: %d\n", ret);
+		return;
+	}
+
+	if (cq->comp_handler)
+		cq->comp_handler(cq, cq->cq_context);
+
+	if (cq->poll_ctx == IB_POLL_DIRECT) {
+		while (!wait_for_completion_timeout(&sdrain.done, HZ / 10))
+			ib_process_cq_direct(cq, -1);
+	} else {
+		wait_for_completion(&sdrain.done);
+	}
+}
+
+void mana_ib_drain_rq(struct ib_qp *ibqp)
+{
+	struct ib_qp_attr attr = { .qp_state = IB_QPS_ERR };
+	struct mana_ib_drain_cqe rdrain;
+	struct ib_recv_wr rwr = {
+		.next = NULL,
+		.wr_cqe = &rdrain.cqe,
+	};
+	struct ib_cq *cq = ibqp->recv_cq;
+	int ret;
+
+	ret = ib_modify_qp(ibqp, &attr, IB_QP_STATE);
+	if (ret) {
+		ibdev_err(ibqp->device, "Failed to drain RQ: modify QP returned %d\n", ret);
+		return;
+	}
+
+	rdrain.cqe.done = mana_ib_drain_qp_done;
+	init_completion(&rdrain.done);
+
+	ret = ib_post_recv(ibqp, &rwr, NULL);
+	if (ret) {
+		ibdev_err(ibqp->device, "Failed to post RQ drain WR: %d\n", ret);
+		return;
+	}
+
+	if (cq->comp_handler)
+		cq->comp_handler(cq, cq->cq_context);
+
+	if (cq->poll_ctx == IB_POLL_DIRECT) {
+		while (!wait_for_completion_timeout(&rdrain.done, HZ / 10))
+			ib_process_cq_direct(cq, -1);
+	} else {
+		wait_for_completion(&rdrain.done);
+	}
+}
-- 
2.43.0