RDMA/siw: Remove NETDEV_GOING_DOWN event handler

Toggling link while running NVME-oF over siw hits a kernel panic
due to race condition within siw_handler and ib_destroy_qp().
The IB_EVENT_PORT_ERR event can alone handle destroying qps.
therefore remove unwanted processing in siw.

Suggested-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Showrya M N <showrya@chelsio.com>
Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Link: https://lore.kernel.org/r/20240724085428.3813-1-showrya@chelsio.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

Author: Showrya M N

drivers/infiniband/sw/siw/siw.h

@@ -94,8 +94,6 @@ struct siw_device {
 	atomic_t num_mr;
 	atomic_t num_srq;
 	atomic_t num_ctx;
-
-	struct work_struct netdev_down;
 };
 
 struct siw_ucontext {

drivers/infiniband/sw/siw/siw_main.c

@@ -364,39 +364,6 @@ static struct siw_device *siw_device_create(struct net_device *netdev)
 	return NULL;
 }
 
-/*
- * Network link becomes unavailable. Mark all
- * affected QP's accordingly.
- */
-static void siw_netdev_down(struct work_struct *work)
-{
-	struct siw_device *sdev =
-		container_of(work, struct siw_device, netdev_down);
-
-	struct siw_qp_attrs qp_attrs;
-	struct list_head *pos, *tmp;
-
-	memset(&qp_attrs, 0, sizeof(qp_attrs));
-	qp_attrs.state = SIW_QP_STATE_ERROR;
-
-	list_for_each_safe(pos, tmp, &sdev->qp_list) {
-		struct siw_qp *qp = list_entry(pos, struct siw_qp, devq);
-
-		down_write(&qp->state_lock);
-		WARN_ON(siw_qp_modify(qp, &qp_attrs, SIW_QP_ATTR_STATE));
-		up_write(&qp->state_lock);
-	}
-	ib_device_put(&sdev->base_dev);
-}
-
-static void siw_device_goes_down(struct siw_device *sdev)
-{
-	if (ib_device_try_get(&sdev->base_dev)) {
-		INIT_WORK(&sdev->netdev_down, siw_netdev_down);
-		schedule_work(&sdev->netdev_down);
-	}
-}
-
 static int siw_netdev_event(struct notifier_block *nb, unsigned long event,
 			    void *arg)
 {
@@ -418,10 +385,6 @@ static int siw_netdev_event(struct notifier_block *nb, unsigned long event,
 		siw_port_event(sdev, 1, IB_EVENT_PORT_ACTIVE);
 		break;
 
-	case NETDEV_GOING_DOWN:
-		siw_device_goes_down(sdev);
-		break;
-
 	case NETDEV_DOWN:
 		sdev->state = IB_PORT_DOWN;
 		siw_port_event(sdev, 1, IB_EVENT_PORT_ERR);