sfc: Refactor efx_mcdi_poll() by introducing efx_mcdi_poll_once()

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

drivers/net/ethernet/sfc/mcdi.c

@@ -50,6 +50,7 @@ struct efx_mcdi_async_param {
 static void efx_mcdi_timeout_async(unsigned long context);
 static int efx_mcdi_drv_attach(struct efx_nic *efx, bool driver_operating,
 			       bool *was_attached_out);
+static bool efx_mcdi_poll_once(struct efx_nic *efx);
 
 static inline struct efx_mcdi_iface *efx_mcdi(struct efx_nic *efx)
 {
@@ -237,6 +238,21 @@ static void efx_mcdi_read_response_header(struct efx_nic *efx)
 	}
 }
 
+static bool efx_mcdi_poll_once(struct efx_nic *efx)
+{
+	struct efx_mcdi_iface *mcdi = efx_mcdi(efx);
+
+	rmb();
+	if (!efx->type->mcdi_poll_response(efx))
+		return false;
+
+	spin_lock_bh(&mcdi->iface_lock);
+	efx_mcdi_read_response_header(efx);
+	spin_unlock_bh(&mcdi->iface_lock);
+
+	return true;
+}
+
 static int efx_mcdi_poll(struct efx_nic *efx)
 {
 	struct efx_mcdi_iface *mcdi = efx_mcdi(efx);
@@ -272,18 +288,13 @@ static int efx_mcdi_poll(struct efx_nic *efx)
 
 		time = jiffies;
 
-		rmb();
-		if (efx->type->mcdi_poll_response(efx))
+		if (efx_mcdi_poll_once(efx))
 			break;
 
 		if (time_after(time, finish))
 			return -ETIMEDOUT;
 	}
 
-	spin_lock_bh(&mcdi->iface_lock);
-	efx_mcdi_read_response_header(efx);
-	spin_unlock_bh(&mcdi->iface_lock);
-
 	/* Return rc=0 like wait_event_timeout() */
 	return 0;
 }