IB/ipath: Fix many locking issues when switching to error state

The send DMA hardware queue voided a number of prior assumptions about
when a send is complete which led to completions being generated out of
order.  There were also a number of locking issues when switching the QP
to the error or reset states, and we implement the IB_QPS_SQD state.

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 97 insertions, 54 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_rc.c b/drivers/infiniband/hw/ipath/ipath_rc.c
index b4b26c3aa613..5b5276a270bc 100644
--- a/drivers/infiniband/hw/ipath/ipath_rc.c
+++ b/drivers/infiniband/hw/ipath/ipath_rc.c
@@ -92,6 +92,10 @@ static int ipath_make_rc_ack(struct ipath_ibdev *dev, struct ipath_qp *qp,
 	u32 bth0;
 	u32 bth2;
 
+	/* Don't send an ACK if we aren't supposed to. */
+	if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK))
+		goto bail;
+
 	/* header size in 32-bit words LRH+BTH = (8+12)/4. */
 	hwords = 5;
 
@@ -238,14 +242,25 @@ int ipath_make_rc_req(struct ipath_qp *qp)
 	    ipath_make_rc_ack(dev, qp, ohdr, pmtu))
 		goto done;
 
-	if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK) ||
-	    qp->s_rnr_timeout || qp->s_wait_credit)
-		goto bail;
+	if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK)) {
+		if (!(ib_ipath_state_ops[qp->state] & IPATH_FLUSH_SEND))
+			goto bail;
+		/* We are in the error state, flush the work request. */
+		if (qp->s_last == qp->s_head)
+			goto bail;
+		/* If DMAs are in progress, we can't flush immediately. */
+		if (atomic_read(&qp->s_dma_busy)) {
+			qp->s_flags |= IPATH_S_WAIT_DMA;
+			goto bail;
+		}
+		wqe = get_swqe_ptr(qp, qp->s_last);
+		ipath_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
+		goto done;
+	}
 
-	/* Limit the number of packets sent without an ACK. */
-	if (ipath_cmp24(qp->s_psn, qp->s_last_psn + IPATH_PSN_CREDIT) > 0) {
-		qp->s_wait_credit = 1;
-		dev->n_rc_stalls++;
+	/* Leave BUSY set until RNR timeout. */
+	if (qp->s_rnr_timeout) {
+		qp->s_flags |= IPATH_S_WAITING;
 		goto bail;
 	}
 
@@ -257,6 +272,9 @@ int ipath_make_rc_req(struct ipath_qp *qp)
 	wqe = get_swqe_ptr(qp, qp->s_cur);
 	switch (qp->s_state) {
 	default:
+		if (!(ib_ipath_state_ops[qp->state] &
+		    IPATH_PROCESS_NEXT_SEND_OK))
+			goto bail;
 		/*
 		 * Resend an old request or start a new one.
 		 *
@@ -294,8 +312,10 @@ int ipath_make_rc_req(struct ipath_qp *qp)
 		case IB_WR_SEND_WITH_IMM:
 			/* If no credit, return. */
 			if (qp->s_lsn != (u32) -1 &&
-			    ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0)
+			    ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0) {
+				qp->s_flags |= IPATH_S_WAIT_SSN_CREDIT;
 				goto bail;
+			}
 			wqe->lpsn = wqe->psn;
 			if (len > pmtu) {
 				wqe->lpsn += (len - 1) / pmtu;
@@ -325,8 +345,10 @@ int ipath_make_rc_req(struct ipath_qp *qp)
 		case IB_WR_RDMA_WRITE_WITH_IMM:
 			/* If no credit, return. */
 			if (qp->s_lsn != (u32) -1 &&
-			    ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0)
+			    ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0) {
+				qp->s_flags |= IPATH_S_WAIT_SSN_CREDIT;
 				goto bail;
+			}
 			ohdr->u.rc.reth.vaddr =
 				cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
 			ohdr->u.rc.reth.rkey =
@@ -570,7 +592,11 @@ int ipath_make_rc_req(struct ipath_qp *qp)
 	ipath_make_ruc_header(dev, qp, ohdr, bth0 | (qp->s_state << 24), bth2);
 done:
 	ret = 1;
+	goto unlock;
+
 bail:
+	qp->s_flags &= ~IPATH_S_BUSY;
+unlock:
 	spin_unlock_irqrestore(&qp->s_lock, flags);
 	return ret;
 }
@@ -606,7 +632,11 @@ static void send_rc_ack(struct ipath_qp *qp)
 
 	spin_unlock_irqrestore(&qp->s_lock, flags);
 
+	/* Don't try to send ACKs if the link isn't ACTIVE */
 	dd = dev->dd;
+	if (!(dd->ipath_flags & IPATH_LINKACTIVE))
+		goto done;
+
 	piobuf = ipath_getpiobuf(dd, 0, NULL);
 	if (!piobuf) {
 		/*
@@ -668,15 +698,16 @@ static void send_rc_ack(struct ipath_qp *qp)
 	goto done;
 
 queue_ack:
-	dev->n_rc_qacks++;
-	qp->s_flags |= IPATH_S_ACK_PENDING;
-	qp->s_nak_state = qp->r_nak_state;
-	qp->s_ack_psn = qp->r_ack_psn;
+	if (ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK) {
+		dev->n_rc_qacks++;
+		qp->s_flags |= IPATH_S_ACK_PENDING;
+		qp->s_nak_state = qp->r_nak_state;
+		qp->s_ack_psn = qp->r_ack_psn;
+
+		/* Schedule the send tasklet. */
+		ipath_schedule_send(qp);
+	}
 	spin_unlock_irqrestore(&qp->s_lock, flags);
-
-	/* Call ipath_do_rc_send() in another thread. */
-	tasklet_hi_schedule(&qp->s_task);
-
 done:
 	return;
 }
@@ -735,7 +766,7 @@ static void reset_psn(struct ipath_qp *qp, u32 psn)
 	/*
 	 * Set the state to restart in the middle of a request.
 	 * Don't change the s_sge, s_cur_sge, or s_cur_size.
-	 * See ipath_do_rc_send().
+	 * See ipath_make_rc_req().
 	 */
 	switch (opcode) {
 	case IB_WR_SEND:
@@ -801,7 +832,7 @@ void ipath_restart_rc(struct ipath_qp *qp, u32 psn)
 		dev->n_rc_resends += (qp->s_psn - psn) & IPATH_PSN_MASK;
 
 	reset_psn(qp, psn);
-	tasklet_hi_schedule(&qp->s_task);
+	ipath_schedule_send(qp);
 
 bail:
 	return;
@@ -809,13 +840,7 @@ bail:
 
 static inline void update_last_psn(struct ipath_qp *qp, u32 psn)
 {
-	if (qp->s_last_psn != psn) {
-		qp->s_last_psn = psn;
-		if (qp->s_wait_credit) {
-			qp->s_wait_credit = 0;
-			tasklet_hi_schedule(&qp->s_task);
-		}
-	}
+	qp->s_last_psn = psn;
 }
 
 /**
@@ -915,14 +940,10 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode,
 		     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
 			qp->s_num_rd_atomic--;
 			/* Restart sending task if fence is complete */
-			if ((qp->s_flags & IPATH_S_FENCE_PENDING) &&
-			    !qp->s_num_rd_atomic) {
-				qp->s_flags &= ~IPATH_S_FENCE_PENDING;
-				tasklet_hi_schedule(&qp->s_task);
-			} else if (qp->s_flags & IPATH_S_RDMAR_PENDING) {
-				qp->s_flags &= ~IPATH_S_RDMAR_PENDING;
-				tasklet_hi_schedule(&qp->s_task);
-			}
+			if (((qp->s_flags & IPATH_S_FENCE_PENDING) &&
+			     !qp->s_num_rd_atomic) ||
+			    qp->s_flags & IPATH_S_RDMAR_PENDING)
+				ipath_schedule_send(qp);
 		}
 		/* Post a send completion queue entry if requested. */
 		if (!(qp->s_flags & IPATH_S_SIGNAL_REQ_WR) ||
@@ -956,6 +977,8 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode,
 		} else {
 			if (++qp->s_last >= qp->s_size)
 				qp->s_last = 0;
+			if (qp->state == IB_QPS_SQD && qp->s_last == qp->s_cur)
+				qp->s_draining = 0;
 			if (qp->s_last == qp->s_tail)
 				break;
 			wqe = get_swqe_ptr(qp, qp->s_last);
@@ -979,7 +1002,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode,
 			 */
 			if (ipath_cmp24(qp->s_psn, psn) <= 0) {
 				reset_psn(qp, psn + 1);
-				tasklet_hi_schedule(&qp->s_task);
+				ipath_schedule_send(qp);
 			}
 		} else if (ipath_cmp24(qp->s_psn, psn) <= 0) {
 			qp->s_state = OP(SEND_LAST);
@@ -1018,6 +1041,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode,
 			ib_ipath_rnr_table[(aeth >> IPATH_AETH_CREDIT_SHIFT) &
 					   IPATH_AETH_CREDIT_MASK];
 		ipath_insert_rnr_queue(qp);
+		ipath_schedule_send(qp);
 		goto bail;
 
 	case 3:		/* NAK */
@@ -1108,6 +1132,10 @@ static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
 
 	spin_lock_irqsave(&qp->s_lock, flags);
 
+	/* Double check we can process this now that we hold the s_lock. */
+	if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK))
+		goto ack_done;
+
 	/* Ignore invalid responses. */
 	if (ipath_cmp24(psn, qp->s_next_psn) >= 0)
 		goto ack_done;
@@ -1343,7 +1371,12 @@ static inline int ipath_rc_rcv_error(struct ipath_ibdev *dev,
 	psn &= IPATH_PSN_MASK;
 	e = NULL;
 	old_req = 1;
+
 	spin_lock_irqsave(&qp->s_lock, flags);
+	/* Double check we can process this now that we hold the s_lock. */
+	if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK))
+		goto unlock_done;
+
 	for (i = qp->r_head_ack_queue; ; i = prev) {
 		if (i == qp->s_tail_ack_queue)
 			old_req = 0;
@@ -1471,7 +1504,7 @@ static inline int ipath_rc_rcv_error(struct ipath_ibdev *dev,
 		break;
 	}
 	qp->r_nak_state = 0;
-	tasklet_hi_schedule(&qp->s_task);
+	ipath_schedule_send(qp);
 
 unlock_done:
 	spin_unlock_irqrestore(&qp->s_lock, flags);
@@ -1503,18 +1536,15 @@ void ipath_rc_error(struct ipath_qp *qp, enum ib_wc_status err)
 
 static inline void ipath_update_ack_queue(struct ipath_qp *qp, unsigned n)
 {
-	unsigned long flags;
 	unsigned next;
 
 	next = n + 1;
 	if (next > IPATH_MAX_RDMA_ATOMIC)
 		next = 0;
-	spin_lock_irqsave(&qp->s_lock, flags);
 	if (n == qp->s_tail_ack_queue) {
 		qp->s_tail_ack_queue = next;
 		qp->s_ack_state = OP(ACKNOWLEDGE);
 	}
-	spin_unlock_irqrestore(&qp->s_lock, flags);
 }
 
 /**
@@ -1543,6 +1573,7 @@ void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 	int diff;
 	struct ib_reth *reth;
 	int header_in_data;
+	unsigned long flags;
 
 	/* Validate the SLID. See Ch. 9.6.1.5 */
 	if (unlikely(be16_to_cpu(hdr->lrh[3]) != qp->remote_ah_attr.dlid))
@@ -1690,9 +1721,8 @@ void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 			goto nack_inv;
 		ipath_copy_sge(&qp->r_sge, data, tlen);
 		qp->r_msn++;
-		if (!qp->r_wrid_valid)
+		if (!test_and_clear_bit(IPATH_R_WRID_VALID, &qp->r_aflags))
 			break;
-		qp->r_wrid_valid = 0;
 		wc.wr_id = qp->r_wr_id;
 		wc.status = IB_WC_SUCCESS;
 		if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
@@ -1764,9 +1794,13 @@ void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 		next = qp->r_head_ack_queue + 1;
 		if (next > IPATH_MAX_RDMA_ATOMIC)
 			next = 0;
+		spin_lock_irqsave(&qp->s_lock, flags);
+		/* Double check we can process this while holding the s_lock. */
+		if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK))
+			goto unlock;
 		if (unlikely(next == qp->s_tail_ack_queue)) {
 			if (!qp->s_ack_queue[next].sent)
-				goto nack_inv;
+				goto nack_inv_unlck;
 			ipath_update_ack_queue(qp, next);
 		}
 		e = &qp->s_ack_queue[qp->r_head_ack_queue];
@@ -1787,7 +1821,7 @@ void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 			ok = ipath_rkey_ok(qp, &e->rdma_sge, len, vaddr,
 					   rkey, IB_ACCESS_REMOTE_READ);
 			if (unlikely(!ok))
-				goto nack_acc;
+				goto nack_acc_unlck;
 			/*
 			 * Update the next expected PSN.  We add 1 later
 			 * below, so only add the remainder here.
@@ -1814,13 +1848,12 @@ void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 		qp->r_psn++;
 		qp->r_state = opcode;
 		qp->r_nak_state = 0;
-		barrier();
 		qp->r_head_ack_queue = next;
 
-		/* Call ipath_do_rc_send() in another thread. */
-		tasklet_hi_schedule(&qp->s_task);
+		/* Schedule the send tasklet. */
+		ipath_schedule_send(qp);
 
-		goto done;
+		goto unlock;
 	}
 
 	case OP(COMPARE_SWAP):
@@ -1839,9 +1872,13 @@ void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 		next = qp->r_head_ack_queue + 1;
 		if (next > IPATH_MAX_RDMA_ATOMIC)
 			next = 0;
+		spin_lock_irqsave(&qp->s_lock, flags);
+		/* Double check we can process this while holding the s_lock. */
+		if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK))
+			goto unlock;
 		if (unlikely(next == qp->s_tail_ack_queue)) {
 			if (!qp->s_ack_queue[next].sent)
-				goto nack_inv;
+				goto nack_inv_unlck;
 			ipath_update_ack_queue(qp, next);
 		}
 		if (!header_in_data)
@@ -1851,13 +1888,13 @@ void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 		vaddr = ((u64) be32_to_cpu(ateth->vaddr[0]) << 32) |
 			be32_to_cpu(ateth->vaddr[1]);
 		if (unlikely(vaddr & (sizeof(u64) - 1)))
-			goto nack_inv;
+			goto nack_inv_unlck;
 		rkey = be32_to_cpu(ateth->rkey);
 		/* Check rkey & NAK */
 		if (unlikely(!ipath_rkey_ok(qp, &qp->r_sge,
 					    sizeof(u64), vaddr, rkey,
 					    IB_ACCESS_REMOTE_ATOMIC)))
-			goto nack_acc;
+			goto nack_acc_unlck;
 		/* Perform atomic OP and save result. */
 		maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
 		sdata = be64_to_cpu(ateth->swap_data);
@@ -1874,13 +1911,12 @@ void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 		qp->r_psn++;
 		qp->r_state = opcode;
 		qp->r_nak_state = 0;
-		barrier();
 		qp->r_head_ack_queue = next;
 
-		/* Call ipath_do_rc_send() in another thread. */
-		tasklet_hi_schedule(&qp->s_task);
+		/* Schedule the send tasklet. */
+		ipath_schedule_send(qp);
 
-		goto done;
+		goto unlock;
 	}
 
 	default:
@@ -1901,19 +1937,26 @@ rnr_nak:
 	qp->r_ack_psn = qp->r_psn;
 	goto send_ack;
 
+nack_inv_unlck:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
 nack_inv:
 	ipath_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
 	qp->r_nak_state = IB_NAK_INVALID_REQUEST;
 	qp->r_ack_psn = qp->r_psn;
 	goto send_ack;
 
+nack_acc_unlck:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
 nack_acc:
 	ipath_rc_error(qp, IB_WC_LOC_PROT_ERR);
 	qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
 	qp->r_ack_psn = qp->r_psn;
 send_ack:
 	send_rc_ack(qp);
+	goto done;
 
+unlock:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
 done:
 	return;
 }