octeontx2-pf: handle otx2_mbox_get_rsp errors in otx2_dcbnl.c

Add error pointer check after calling otx2_mbox_get_rsp().

Fixes: 8e67558 ("octeontx2-pf: PFC config support with DCBx")
Signed-off-by: Dipendra Khadka <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Signed-off-by: Andrew Lunn <[email protected]>

Author: Dipendra333

drivers/net/ethernet/marvell/octeontx2/nic/otx2_dcbnl.c

@@ -315,6 +315,11 @@ int otx2_config_priority_flow_ctrl(struct otx2_nic *pfvf)
 	if (!otx2_sync_mbox_msg(&pfvf->mbox)) {
 		rsp = (struct cgx_pfc_rsp *)
 		       otx2_mbox_get_rsp(&pfvf->mbox.mbox, 0, &req->hdr);
+		if (IS_ERR(rsp)) {
+			err = PTR_ERR(rsp);
+			goto unlock;
+		}
+
 		if (req->rx_pause != rsp->rx_pause || req->tx_pause != rsp->tx_pause) {
 			dev_warn(pfvf->dev,
 				 "Failed to config PFC\n");