bnxt_re: Implement the shutdown hook of the L2-RoCE driver interface

When host is shutting down, it invokes the shutdown hook of the
L2 driver where it would attempt to free the MSI-X vectors, but would fail
because some vectors are held by the RoCE driver.
Implement the new hook in the L2 -> RoCE interface which will be invoked so that
the RoCE driver can unregister the device and free up the MSI-X vectors it had
claimed so that L2 can proceed with it's shutdown without failure.

Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/bnxt_re/main.c

@@ -78,6 +78,7 @@ static struct list_head bnxt_re_dev_list = LIST_HEAD_INIT(bnxt_re_dev_list);
 /* Mutex to protect the list of bnxt_re devices added */
 static DEFINE_MUTEX(bnxt_re_dev_lock);
 static struct workqueue_struct *bnxt_re_wq;
+static void bnxt_re_ib_unreg(struct bnxt_re_dev *rdev, bool lock_wait);
 
 /* for handling bnxt_en callbacks later */
 static void bnxt_re_stop(void *p)
@@ -92,11 +93,22 @@ static void bnxt_re_sriov_config(void *p, int num_vfs)
 {
 }
 
+static void bnxt_re_shutdown(void *p)
+{
+	struct bnxt_re_dev *rdev = p;
+
+	if (!rdev)
+		return;
+
+	bnxt_re_ib_unreg(rdev, false);
+}
+
 static struct bnxt_ulp_ops bnxt_re_ulp_ops = {
 	.ulp_async_notifier = NULL,
 	.ulp_stop = bnxt_re_stop,
 	.ulp_start = bnxt_re_start,
-	.ulp_sriov_config = bnxt_re_sriov_config
+	.ulp_sriov_config = bnxt_re_sriov_config,
+	.ulp_shutdown = bnxt_re_shutdown
 };
 
 /* RoCE -> Net driver */