RDMA/i40iw: Add qp table lock around AE processing

QP may be freed during Async Event processing.
Add a lock around QP table to prevent it.
Signed-off-by: Mustafa Ismail <mustafa.ismail@intel.com>
Signed-off-by: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/i40iw/i40iw.h

@@ -254,6 +254,7 @@ struct i40iw_device {
 	u32 arp_table_size;
 	u32 next_arp_index;
 	spinlock_t resource_lock; /* hw resource access */
+	spinlock_t qptable_lock;
 	u32 vendor_id;
 	u32 vendor_part_id;
 	u32 of_device_registered;

drivers/infiniband/hw/i40iw/i40iw_hw.c

@@ -106,6 +106,7 @@ u32 i40iw_initialize_hw_resources(struct i40iw_device *iwdev)
 	set_bit(2, iwdev->allocated_pds);
 
 	spin_lock_init(&iwdev->resource_lock);
+	spin_lock_init(&iwdev->qptable_lock);
 	mrdrvbits = 24 - get_count_order(iwdev->max_mr);
 	iwdev->mr_stagmask = ~(((1 << mrdrvbits) - 1) << (32 - mrdrvbits));
 	return 0;
@@ -301,11 +302,15 @@ void i40iw_process_aeq(struct i40iw_device *iwdev)
 			    "%s ae_id = 0x%x bool qp=%d qp_id = %d\n",
 			    __func__, info->ae_id, info->qp, info->qp_cq_id);
 		if (info->qp) {
+			spin_lock_irqsave(&iwdev->qptable_lock, flags);
 			iwqp = iwdev->qp_table[info->qp_cq_id];
 			if (!iwqp) {
+				spin_unlock_irqrestore(&iwdev->qptable_lock, flags);
 				i40iw_pr_err("qp_id %d is already freed\n", info->qp_cq_id);
 				continue;
 			}
+			i40iw_add_ref(&iwqp->ibqp);
+			spin_unlock_irqrestore(&iwdev->qptable_lock, flags);
 			qp = &iwqp->sc_qp;
 			spin_lock_irqsave(&iwqp->lock, flags);
 			iwqp->hw_tcp_state = info->tcp_state;
@@ -411,6 +416,8 @@ void i40iw_process_aeq(struct i40iw_device *iwdev)
 				i40iw_terminate_connection(qp, info);
 				break;
 		}
+		if (info->qp)
+			i40iw_rem_ref(&iwqp->ibqp);
 	} while (1);
 
 	if (aeqcnt)

drivers/infiniband/hw/i40iw/i40iw_utils.c

@@ -506,14 +506,19 @@ void i40iw_rem_ref(struct ib_qp *ibqp)
 	struct cqp_commands_info *cqp_info;
 	struct i40iw_device *iwdev;
 	u32 qp_num;
+	unsigned long flags;
 
 	iwqp = to_iwqp(ibqp);
-	if (!atomic_dec_and_test(&iwqp->refcount))
+	iwdev = iwqp->iwdev;
+	spin_lock_irqsave(&iwdev->qptable_lock, flags);
+	if (!atomic_dec_and_test(&iwqp->refcount)) {
+		spin_unlock_irqrestore(&iwdev->qptable_lock, flags);
 		return;
+	}
 
-	iwdev = iwqp->iwdev;
 	qp_num = iwqp->ibqp.qp_num;
 	iwdev->qp_table[qp_num] = NULL;
+	spin_unlock_irqrestore(&iwdev->qptable_lock, flags);
 	cqp_request = i40iw_get_cqp_request(&iwdev->cqp, false);
 	if (!cqp_request)
 		return;