cxgb4 : Disable recursive mailbox commands when enabling vi

Enabling a Virtual Interface can result in an interrupt during the processing
 of the VI Enable command and, in some paths, result in an attempt to issue
another command in the interrupt context, eventually crashing the system. Thus,
 we disable interrupts during the course of the VI Enable command and ensure
enable doesn't sleep.

Signed-off-by: Anish Bhatt <anish@chelsio.com>
Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
index 8b46534..4247356 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -673,9 +673,12 @@
 	if (ret == 0)
 		ret = t4_link_start(pi->adapter, mb, pi->tx_chan,
 				    &pi->link_cfg);
-	if (ret == 0)
+	if (ret == 0) {
+		local_bh_disable();
 		ret = t4_enable_vi_params(pi->adapter, mb, pi->viid, true,
 					  true, CXGB4_DCB_ENABLED);
+		local_bh_enable();
+	}
 
 	return ret;
 }
diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
index 448bec1..a853133 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
@@ -3558,7 +3558,7 @@
 	c.ien_to_len16 = htonl(FW_VI_ENABLE_CMD_IEN(rx_en) |
 			       FW_VI_ENABLE_CMD_EEN(tx_en) | FW_LEN16(c) |
 			       FW_VI_ENABLE_CMD_DCB_INFO(dcb_en));
-	return t4_wr_mbox(adap, mbox, &c, sizeof(c), NULL);
+	return t4_wr_mbox_ns(adap, mbox, &c, sizeof(c), NULL);
 }
 
 /**