IB/mlx5: Reset flow support for IB kernel ULPs

The driver exposes interfaces that directly relate to HW state.
Upon fatal error, consumers of these interfaces (ULPs) that rely
on completion of all their posted work-request could hang, thereby
introducing dependencies in shutdown order. To prevent this from
happening, we manage the relevant resources (CQs, QPs) that are used
by the device. Upon a fatal error, we now generate simulated
completions for outstanding WQEs that were not completed at the
time the HW was reset.

It includes invoking the completion event handler for all involved
CQs so that the ULPs will poll those CQs. When polled we return
simulated CQEs with IB_WC_WR_FLUSH_ERR return code enabling ULPs
to clean up their  resources and not wait forever for completions
upon receiving remove_one.

The above change requires an extra check in the data path to make
sure that when device is in error state, the simulated CQEs will
be returned and no further WQEs will be posted.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 79 insertions, 19 deletions

diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index f9df4b527a11..9004905d3d93 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -77,6 +77,10 @@ struct mlx5_wqe_eth_pad {
 	u8 rsvd0[16];
 };
 
+static void get_cqs(enum ib_qp_type qp_type,
+		    struct ib_cq *ib_send_cq, struct ib_cq *ib_recv_cq,
+		    struct mlx5_ib_cq **send_cq, struct mlx5_ib_cq **recv_cq);
+
 static int is_qp0(enum ib_qp_type qp_type)
 {
 	return qp_type == IB_QPT_SMI;
@@ -609,6 +613,11 @@ static int to_mlx5_st(enum ib_qp_type type)
 	}
 }
 
+static void mlx5_ib_lock_cqs(struct mlx5_ib_cq *send_cq,
+			     struct mlx5_ib_cq *recv_cq);
+static void mlx5_ib_unlock_cqs(struct mlx5_ib_cq *send_cq,
+			       struct mlx5_ib_cq *recv_cq);
+
 static int uuarn_to_uar_index(struct mlx5_uuar_info *uuari, int uuarn)
 {
 	return uuari->uars[uuarn / MLX5_BF_REGS_PER_PAGE].index;
@@ -1457,6 +1466,9 @@ static int create_qp_common(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 	struct mlx5_ib_create_qp_resp resp;
 	struct mlx5_create_qp_mbox_in *in;
 	struct mlx5_ib_create_qp ucmd;
+	struct mlx5_ib_cq *send_cq;
+	struct mlx5_ib_cq *recv_cq;
+	unsigned long flags;
 	int inlen = sizeof(*in);
 	int err;
 	u32 uidx = MLX5_IB_DEFAULT_UIDX;
@@ -1714,6 +1726,23 @@ static int create_qp_common(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 	base->container_mibqp = qp;
 	base->mqp.event = mlx5_ib_qp_event;
 
+	get_cqs(init_attr->qp_type, init_attr->send_cq, init_attr->recv_cq,
+		&send_cq, &recv_cq);
+	spin_lock_irqsave(&dev->reset_flow_resource_lock, flags);
+	mlx5_ib_lock_cqs(send_cq, recv_cq);
+	/* Maintain device to QPs access, needed for further handling via reset
+	 * flow
+	 */
+	list_add_tail(&qp->qps_list, &dev->qp_list);
+	/* Maintain CQ to QPs access, needed for further handling via reset flow
+	 */
+	if (send_cq)
+		list_add_tail(&qp->cq_send_list, &send_cq->list_send_qp);
+	if (recv_cq)
+		list_add_tail(&qp->cq_recv_list, &recv_cq->list_recv_qp);
+	mlx5_ib_unlock_cqs(send_cq, recv_cq);
+	spin_unlock_irqrestore(&dev->reset_flow_resource_lock, flags);
+
 	return 0;
 
 err_create:
@@ -1732,23 +1761,23 @@ static void mlx5_ib_lock_cqs(struct mlx5_ib_cq *send_cq, struct mlx5_ib_cq *recv
 	if (send_cq) {
 		if (recv_cq) {
 			if (send_cq->mcq.cqn < recv_cq->mcq.cqn)  {
-				spin_lock_irq(&send_cq->lock);
+				spin_lock(&send_cq->lock);
 				spin_lock_nested(&recv_cq->lock,
 						 SINGLE_DEPTH_NESTING);
 			} else if (send_cq->mcq.cqn == recv_cq->mcq.cqn) {
-				spin_lock_irq(&send_cq->lock);
+				spin_lock(&send_cq->lock);
 				__acquire(&recv_cq->lock);
 			} else {
-				spin_lock_irq(&recv_cq->lock);
+				spin_lock(&recv_cq->lock);
 				spin_lock_nested(&send_cq->lock,
 						 SINGLE_DEPTH_NESTING);
 			}
 		} else {
-			spin_lock_irq(&send_cq->lock);
+			spin_lock(&send_cq->lock);
 			__acquire(&recv_cq->lock);
 		}
 	} else if (recv_cq) {
-		spin_lock_irq(&recv_cq->lock);
+		spin_lock(&recv_cq->lock);
 		__acquire(&send_cq->lock);
 	} else {
 		__acquire(&send_cq->lock);
@@ -1763,21 +1792,21 @@ static void mlx5_ib_unlock_cqs(struct mlx5_ib_cq *send_cq, struct mlx5_ib_cq *re
 		if (recv_cq) {
 			if (send_cq->mcq.cqn < recv_cq->mcq.cqn)  {
 				spin_unlock(&recv_cq->lock);
-				spin_unlock_irq(&send_cq->lock);
+				spin_unlock(&send_cq->lock);
 			} else if (send_cq->mcq.cqn == recv_cq->mcq.cqn) {
 				__release(&recv_cq->lock);
-				spin_unlock_irq(&send_cq->lock);
+				spin_unlock(&send_cq->lock);
 			} else {
 				spin_unlock(&send_cq->lock);
-				spin_unlock_irq(&recv_cq->lock);
+				spin_unlock(&recv_cq->lock);
 			}
 		} else {
 			__release(&recv_cq->lock);
-			spin_unlock_irq(&send_cq->lock);
+			spin_unlock(&send_cq->lock);
 		}
 	} else if (recv_cq) {
 		__release(&send_cq->lock);
-		spin_unlock_irq(&recv_cq->lock);
+		spin_unlock(&recv_cq->lock);
 	} else {
 		__release(&recv_cq->lock);
 		__release(&send_cq->lock);
@@ -1789,17 +1818,18 @@ static struct mlx5_ib_pd *get_pd(struct mlx5_ib_qp *qp)
 	return to_mpd(qp->ibqp.pd);
 }
 
-static void get_cqs(struct mlx5_ib_qp *qp,
+static void get_cqs(enum ib_qp_type qp_type,
+		    struct ib_cq *ib_send_cq, struct ib_cq *ib_recv_cq,
 		    struct mlx5_ib_cq **send_cq, struct mlx5_ib_cq **recv_cq)
 {
-	switch (qp->ibqp.qp_type) {
+	switch (qp_type) {
 	case IB_QPT_XRC_TGT:
 		*send_cq = NULL;
 		*recv_cq = NULL;
 		break;
 	case MLX5_IB_QPT_REG_UMR:
 	case IB_QPT_XRC_INI:
-		*send_cq = to_mcq(qp->ibqp.send_cq);
+		*send_cq = ib_send_cq ? to_mcq(ib_send_cq) : NULL;
 		*recv_cq = NULL;
 		break;
 
@@ -1811,8 +1841,8 @@ static void get_cqs(struct mlx5_ib_qp *qp,
 	case IB_QPT_RAW_IPV6:
 	case IB_QPT_RAW_ETHERTYPE:
 	case IB_QPT_RAW_PACKET:
-		*send_cq = to_mcq(qp->ibqp.send_cq);
-		*recv_cq = to_mcq(qp->ibqp.recv_cq);
+		*send_cq = ib_send_cq ? to_mcq(ib_send_cq) : NULL;
+		*recv_cq = ib_recv_cq ? to_mcq(ib_recv_cq) : NULL;
 		break;
 
 	case IB_QPT_MAX:
@@ -1831,6 +1861,7 @@ static void destroy_qp_common(struct mlx5_ib_dev *dev, struct mlx5_ib_qp *qp)
 	struct mlx5_ib_cq *send_cq, *recv_cq;
 	struct mlx5_ib_qp_base *base = &qp->trans_qp.base;
 	struct mlx5_modify_qp_mbox_in *in;
+	unsigned long flags;
 	int err;
 
 	if (qp->ibqp.rwq_ind_tbl) {
@@ -1861,17 +1892,28 @@ static void destroy_qp_common(struct mlx5_ib_dev *dev, struct mlx5_ib_qp *qp)
 				     base->mqp.qpn);
 	}
 
-	get_cqs(qp, &send_cq, &recv_cq);
+	get_cqs(qp->ibqp.qp_type, qp->ibqp.send_cq, qp->ibqp.recv_cq,
+		&send_cq, &recv_cq);
+
+	spin_lock_irqsave(&dev->reset_flow_resource_lock, flags);
+	mlx5_ib_lock_cqs(send_cq, recv_cq);
+	/* del from lists under both locks above to protect reset flow paths */
+	list_del(&qp->qps_list);
+	if (send_cq)
+		list_del(&qp->cq_send_list);
+
+	if (recv_cq)
+		list_del(&qp->cq_recv_list);
 
 	if (qp->create_type == MLX5_QP_KERNEL) {
-		mlx5_ib_lock_cqs(send_cq, recv_cq);
 		__mlx5_ib_cq_clean(recv_cq, base->mqp.qpn,
 				   qp->ibqp.srq ? to_msrq(qp->ibqp.srq) : NULL);
 		if (send_cq != recv_cq)
 			__mlx5_ib_cq_clean(send_cq, base->mqp.qpn,
 					   NULL);
-		mlx5_ib_unlock_cqs(send_cq, recv_cq);
 	}
+	mlx5_ib_unlock_cqs(send_cq, recv_cq);
+	spin_unlock_irqrestore(&dev->reset_flow_resource_lock, flags);
 
 	if (qp->ibqp.qp_type == IB_QPT_RAW_PACKET) {
 		destroy_raw_packet_qp(dev, qp);
@@ -2559,7 +2601,8 @@ static int __mlx5_ib_modify_qp(struct ib_qp *ibqp,
 	}
 
 	pd = get_pd(qp);
-	get_cqs(qp, &send_cq, &recv_cq);
+	get_cqs(qp->ibqp.qp_type, qp->ibqp.send_cq, qp->ibqp.recv_cq,
+		&send_cq, &recv_cq);
 
 	context->flags_pd = cpu_to_be32(pd ? pd->pdn : to_mpd(dev->devr.p0)->pdn);
 	context->cqn_send = send_cq ? cpu_to_be32(send_cq->mcq.cqn) : 0;
@@ -3658,6 +3701,7 @@ int mlx5_ib_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
 {
 	struct mlx5_wqe_ctrl_seg *ctrl = NULL;  /* compiler warning */
 	struct mlx5_ib_dev *dev = to_mdev(ibqp->device);
+	struct mlx5_core_dev *mdev = dev->mdev;
 	struct mlx5_ib_qp *qp;
 	struct mlx5_ib_mr *mr;
 	struct mlx5_wqe_data_seg *dpseg;
@@ -3685,6 +3729,13 @@ int mlx5_ib_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
 
 	spin_lock_irqsave(&qp->sq.lock, flags);
 
+	if (mdev->state == MLX5_DEVICE_STATE_INTERNAL_ERROR) {
+		err = -EIO;
+		*bad_wr = wr;
+		nreq = 0;
+		goto out;
+	}
+
 	for (nreq = 0; wr; nreq++, wr = wr->next) {
 		if (unlikely(wr->opcode >= ARRAY_SIZE(mlx5_ib_opcode))) {
 			mlx5_ib_warn(dev, "\n");
@@ -3986,6 +4037,8 @@ int mlx5_ib_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr,
 	struct mlx5_ib_qp *qp = to_mqp(ibqp);
 	struct mlx5_wqe_data_seg *scat;
 	struct mlx5_rwqe_sig *sig;
+	struct mlx5_ib_dev *dev = to_mdev(ibqp->device);
+	struct mlx5_core_dev *mdev = dev->mdev;
 	unsigned long flags;
 	int err = 0;
 	int nreq;
@@ -3997,6 +4050,13 @@ int mlx5_ib_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr,
 
 	spin_lock_irqsave(&qp->rq.lock, flags);
 
+	if (mdev->state == MLX5_DEVICE_STATE_INTERNAL_ERROR) {
+		err = -EIO;
+		*bad_wr = wr;
+		nreq = 0;
+		goto out;
+	}
+
 	ind = qp->rq.head & (qp->rq.wqe_cnt - 1);
 
 	for (nreq = 0; wr; nreq++, wr = wr->next) {