RDMA/bnxt_re: Fix lifetimes in bnxt_re_task

A work queue cannot just rely on the ib_device not being freed, it must
hold a kref on the memory so that the BNXT_RE_FLAG_IBDEV_REGISTERED check
works.

Fixes: 1ac5a404 ("RDMA/bnxt_re: Add bnxt_re RoCE driver")
Link: https://lore.kernel.org/r/1584117207-2664-3-git-send-email-selvin.xavier@broadcom.comSigned-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/bnxt_re/main.c

@@ -1670,6 +1670,7 @@ static void bnxt_re_task(struct work_struct *work)
 	smp_mb__before_atomic();
 	atomic_dec(&rdev->sched_count);
 exit:
+	put_device(&rdev->ibdev.dev);
 	kfree(re_work);
 }
 
@@ -1735,6 +1736,7 @@ static int bnxt_re_netdev_event(struct notifier_block *notifier,
 		/* Allocate for the deferred task */
 		re_work = kzalloc(sizeof(*re_work), GFP_ATOMIC);
 		if (re_work) {
+			get_device(&rdev->ibdev.dev);
 			re_work->rdev = rdev;
 			re_work->event = event;
 			re_work->vlan_dev = (real_dev == netdev ?