IB/mthca: Make all device methods truly reentrant

Documentation/infiniband/core_locking.txt says:

  All of the methods in struct ib_device exported by a low-level
  driver must be fully reentrant.  The low-level driver is required to
  perform all synchronization necessary to maintain consistency, even
  if multiple function calls using the same object are run
  simultaneously.

However, mthca's modify_qp, modify_srq and resize_cq methods are
currently not reentrant.  Add a mutex to the QP, SRQ and CQ structures
so that these calls can be properly serialized.
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mthca/mthca_cq.c

@@ -822,6 +822,7 @@ int mthca_init_cq(struct mthca_dev *dev, int nent,
 	spin_lock_init(&cq->lock);
 	cq->refcount = 1;
 	init_waitqueue_head(&cq->wait);
+	mutex_init(&cq->mutex);
 
 	memset(cq_context, 0, sizeof *cq_context);
 	cq_context->flags           = cpu_to_be32(MTHCA_CQ_STATUS_OK      |

drivers/infiniband/hw/mthca/mthca_provider.c

@@ -793,18 +793,24 @@ static int mthca_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *uda
 	if (entries < 1 || entries > dev->limits.max_cqes)
 		return -EINVAL;
 
+	mutex_lock(&cq->mutex);
+
 	entries = roundup_pow_of_two(entries + 1);
-	if (entries == ibcq->cqe + 1)
-		return 0;
+	if (entries == ibcq->cqe + 1) {
+		ret = 0;
+		goto out;
+	}
 
 	if (cq->is_kernel) {
 		ret = mthca_alloc_resize_buf(dev, cq, entries);
 		if (ret)
-			return ret;
+			goto out;
 		lkey = cq->resize_buf->buf.mr.ibmr.lkey;
 	} else {
-		if (ib_copy_from_udata(&ucmd, udata, sizeof ucmd))
-			return -EFAULT;
+		if (ib_copy_from_udata(&ucmd, udata, sizeof ucmd)) {
+			ret = -EFAULT;
+			goto out;
+		}
 		lkey = ucmd.lkey;
 	}
 
@@ -821,7 +827,7 @@ static int mthca_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *uda
 			cq->resize_buf = NULL;
 			spin_unlock_irq(&cq->lock);
 		}
-		return ret;
+		goto out;
 	}
 
 	if (cq->is_kernel) {
@@ -848,7 +854,10 @@ static int mthca_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *uda
 	} else
 		ibcq->cqe = entries - 1;
 
-	return 0;
+out:
+	mutex_unlock(&cq->mutex);
+
+	return ret;
 }
 
 static int mthca_destroy_cq(struct ib_cq *cq)

drivers/infiniband/hw/mthca/mthca_provider.h

@@ -214,6 +214,7 @@ struct mthca_cq {
 	int			arm_sn;
 
 	wait_queue_head_t	wait;
+	struct mutex		mutex;
 };
 
 struct mthca_srq {
@@ -237,6 +238,7 @@ struct mthca_srq {
 	struct mthca_mr		mr;
 
 	wait_queue_head_t	wait;
+	struct mutex		mutex;
 };
 
 struct mthca_wq {
@@ -278,6 +280,7 @@ struct mthca_qp {
 	union mthca_buf	       queue;
 
 	wait_queue_head_t      wait;
+	struct mutex	       mutex;
 };
 
 struct mthca_sqp {

drivers/infiniband/hw/mthca/mthca_qp.c

@@ -536,6 +536,8 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
 	u8 status;
 	int err = -EINVAL;
 
+	mutex_lock(&qp->mutex);
+
 	if (attr_mask & IB_QP_CUR_STATE) {
 		cur_state = attr->cur_qp_state;
 	} else {
@@ -553,39 +555,41 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
 			  "%d->%d with attr 0x%08x\n",
 			  qp->transport, cur_state, new_state,
 			  attr_mask);
-		return -EINVAL;
+		goto out;
 	}
 
 	if ((attr_mask & IB_QP_PKEY_INDEX) &&
 	     attr->pkey_index >= dev->limits.pkey_table_len) {
 		mthca_dbg(dev, "P_Key index (%u) too large. max is %d\n",
 			  attr->pkey_index, dev->limits.pkey_table_len-1);
-		return -EINVAL;
+		goto out;
 	}
 
 	if ((attr_mask & IB_QP_PORT) &&
 	    (attr->port_num == 0 || attr->port_num > dev->limits.num_ports)) {
 		mthca_dbg(dev, "Port number (%u) is invalid\n", attr->port_num);
-		return -EINVAL;
+		goto out;
 	}
 
 	if (attr_mask & IB_QP_MAX_QP_RD_ATOMIC &&
 	    attr->max_rd_atomic > dev->limits.max_qp_init_rdma) {
 		mthca_dbg(dev, "Max rdma_atomic as initiator %u too large (max is %d)\n",
 			  attr->max_rd_atomic, dev->limits.max_qp_init_rdma);
-		return -EINVAL;
+		goto out;
 	}
 
 	if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC &&
 	    attr->max_dest_rd_atomic > 1 << dev->qp_table.rdb_shift) {
 		mthca_dbg(dev, "Max rdma_atomic as responder %u too large (max %d)\n",
 			  attr->max_dest_rd_atomic, 1 << dev->qp_table.rdb_shift);
-		return -EINVAL;
+		goto out;
 	}
 
 	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
-	if (IS_ERR(mailbox))
-		return PTR_ERR(mailbox);
+	if (IS_ERR(mailbox)) {
+		err = PTR_ERR(mailbox);
+		goto out;
+	}
 	qp_param = mailbox->buf;
 	qp_context = &qp_param->context;
 	memset(qp_param, 0, sizeof *qp_param);
@@ -618,7 +622,7 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
 		if (attr->path_mtu < IB_MTU_256 || attr->path_mtu > IB_MTU_2048) {
 			mthca_dbg(dev, "path MTU (%u) is invalid\n",
 				  attr->path_mtu);
-			goto out;
+			goto out_mailbox;
 		}
 		qp_context->mtu_msgmax = (attr->path_mtu << 5) | 31;
 	}
@@ -672,7 +676,7 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
 	if (attr_mask & IB_QP_AV) {
 		if (mthca_path_set(dev, &attr->ah_attr, &qp_context->pri_path,
 				   attr_mask & IB_QP_PORT ? attr->port_num : qp->port))
-			goto out;
+			goto out_mailbox;
 
 		qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_PRIMARY_ADDR_PATH);
 	}
@@ -686,18 +690,18 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
 		if (attr->alt_pkey_index >= dev->limits.pkey_table_len) {
 			mthca_dbg(dev, "Alternate P_Key index (%u) too large. max is %d\n",
 				  attr->alt_pkey_index, dev->limits.pkey_table_len-1);
-			goto out;
+			goto out_mailbox;
 		}
 
 		if (attr->alt_port_num == 0 || attr->alt_port_num > dev->limits.num_ports) {
 			mthca_dbg(dev, "Alternate port number (%u) is invalid\n",
 				attr->alt_port_num);
-			goto out;
+			goto out_mailbox;
 		}
 
 		if (mthca_path_set(dev, &attr->alt_ah_attr, &qp_context->alt_path,
 				   attr->alt_ah_attr.port_num))
-			goto out;
+			goto out_mailbox;
 
 		qp_context->alt_path.port_pkey |= cpu_to_be32(attr->alt_pkey_index |
 							      attr->alt_port_num << 24);
@@ -793,12 +797,12 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
 	err = mthca_MODIFY_QP(dev, cur_state, new_state, qp->qpn, 0,
 			      mailbox, sqd_event, &status);
 	if (err)
-		goto out;
+		goto out_mailbox;
 	if (status) {
 		mthca_warn(dev, "modify QP %d->%d returned status %02x.\n",
 			   cur_state, new_state, status);
 		err = -EINVAL;
-		goto out;
+		goto out_mailbox;
 	}
 
 	qp->state = new_state;
@@ -853,8 +857,11 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
 		}
 	}
 
-out:
+out_mailbox:
 	mthca_free_mailbox(dev, mailbox);
+
+out:
+	mutex_unlock(&qp->mutex);
 	return err;
 }
 
@@ -1100,6 +1107,7 @@ static int mthca_alloc_qp_common(struct mthca_dev *dev,
 
 	qp->refcount = 1;
 	init_waitqueue_head(&qp->wait);
+	mutex_init(&qp->mutex);
 	qp->state    	 = IB_QPS_RESET;
 	qp->atomic_rd_en = 0;
 	qp->resp_depth   = 0;

drivers/infiniband/hw/mthca/mthca_srq.c

@@ -243,6 +243,7 @@ int mthca_alloc_srq(struct mthca_dev *dev, struct mthca_pd *pd,
 	spin_lock_init(&srq->lock);
 	srq->refcount = 1;
 	init_waitqueue_head(&srq->wait);
+	mutex_init(&srq->mutex);
 
 	if (mthca_is_memfree(dev))
 		mthca_arbel_init_srq_context(dev, pd, srq, mailbox->buf);
@@ -371,7 +372,11 @@ int mthca_modify_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr,
 	if (attr_mask & IB_SRQ_LIMIT) {
 		if (attr->srq_limit > srq->max)
 			return -EINVAL;
+
+		mutex_lock(&srq->mutex);
 		ret = mthca_ARM_SRQ(dev, srq->srqn, attr->srq_limit, &status);
+		mutex_unlock(&srq->mutex);
+
 		if (ret)
 			return ret;
 		if (status)