drivers: net: xgene: Fix module unload crash - hw resource cleanup

When the driver is configured as kernel module and when it gets
unloaded and reloaded, kernel crash was observed.  This patch
address the hardware resource cleanups by doing the following,

- Added mac_ops->clear() to do prefetch buffer clean up
- Fixed delete freepool buffers logic
- Reordered mac_enable and mac_disable
- Added Tx completion ring free
- Moved down delete_desc_rings after ring cleanup

Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Tested-by: Fushen Chen <fchen@apm.com>
Tested-by: Toan Le <toanle@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 24 deletions

diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
index 8da3860691ee..f79950ab9277 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
@@ -102,25 +102,13 @@ static u8 xgene_enet_hdr_len(const void *data)
 
 static void xgene_enet_delete_bufpool(struct xgene_enet_desc_ring *buf_pool)
 {
-	struct xgene_enet_pdata *pdata = netdev_priv(buf_pool->ndev);
-	struct xgene_enet_raw_desc16 *raw_desc;
-	u32 slots = buf_pool->slots - 1;
-	u32 tail = buf_pool->tail;
-	u32 userinfo;
-	int i, len;
-
-	len = pdata->ring_ops->len(buf_pool);
-	for (i = 0; i < len; i++) {
-		tail = (tail - 1) & slots;
-		raw_desc = &buf_pool->raw_desc16[tail];
+	int i;
 
-		/* Hardware stores descriptor in little endian format */
-		userinfo = GET_VAL(USERINFO, le64_to_cpu(raw_desc->m0));
-		dev_kfree_skb_any(buf_pool->rx_skb[userinfo]);
+	/* Free up the buffers held by hardware */
+	for (i = 0; i < buf_pool->slots; i++) {
+		if (buf_pool->rx_skb[i])
+			dev_kfree_skb_any(buf_pool->rx_skb[i]);
 	}
-
-	pdata->ring_ops->wr_cmd(buf_pool, -len);
-	buf_pool->tail = tail;
 }
 
 static irqreturn_t xgene_enet_rx_irq(const int irq, void *data)
@@ -481,6 +469,7 @@ static int xgene_enet_rx_frame(struct xgene_enet_desc_ring *rx_ring,
 			 XGENE_ENET_MAX_MTU, DMA_FROM_DEVICE);
 	skb_index = GET_VAL(USERINFO, le64_to_cpu(raw_desc->m0));
 	skb = buf_pool->rx_skb[skb_index];
+	buf_pool->rx_skb[skb_index] = NULL;
 
 	/* checking for error */
 	status = (GET_VAL(ELERR, le64_to_cpu(raw_desc->m0)) << LERR_LEN) ||
@@ -720,9 +709,6 @@ static int xgene_enet_open(struct net_device *ndev)
 	if (ret)
 		return ret;
 
-	mac_ops->tx_enable(pdata);
-	mac_ops->rx_enable(pdata);
-
 	xgene_enet_napi_enable(pdata);
 	ret = xgene_enet_register_irq(ndev);
 	if (ret)
@@ -735,6 +721,8 @@ static int xgene_enet_open(struct net_device *ndev)
 		netif_carrier_off(ndev);
 	}
 
+	mac_ops->tx_enable(pdata);
+	mac_ops->rx_enable(pdata);
 	netif_start_queue(ndev);
 
 	return ret;
@@ -747,15 +735,14 @@ static int xgene_enet_close(struct net_device *ndev)
 	int i;
 
 	netif_stop_queue(ndev);
+	mac_ops->tx_disable(pdata);
+	mac_ops->rx_disable(pdata);
 
 	if (pdata->phy_mode == PHY_INTERFACE_MODE_RGMII)
 		phy_stop(pdata->phy_dev);
 	else
 		cancel_delayed_work_sync(&pdata->link_work);
 
-	mac_ops->tx_disable(pdata);
-	mac_ops->rx_disable(pdata);
-
 	xgene_enet_free_irq(ndev);
 	xgene_enet_napi_disable(pdata);
 	for (i = 0; i < pdata->rxq_cnt; i++)
@@ -785,6 +772,9 @@ static void xgene_enet_delete_desc_rings(struct xgene_enet_pdata *pdata)
 		ring = pdata->tx_ring[i];
 		if (ring) {
 			xgene_enet_delete_ring(ring);
+			pdata->port_ops->clear(pdata, ring);
+			if (pdata->cq_cnt)
+				xgene_enet_delete_ring(ring->cp_ring);
 			pdata->tx_ring[i] = NULL;
 		}
 	}
@@ -795,6 +785,7 @@ static void xgene_enet_delete_desc_rings(struct xgene_enet_pdata *pdata)
 			buf_pool = ring->buf_pool;
 			xgene_enet_delete_bufpool(buf_pool);
 			xgene_enet_delete_ring(buf_pool);
+			pdata->port_ops->clear(pdata, buf_pool);
 			xgene_enet_delete_ring(ring);
 			pdata->rx_ring[i] = NULL;
 		}
@@ -1682,8 +1673,8 @@ static int xgene_enet_remove(struct platform_device *pdev)
 	if (pdata->phy_mode == PHY_INTERFACE_MODE_RGMII)
 		xgene_enet_mdio_remove(pdata);
 	unregister_netdev(ndev);
-	xgene_enet_delete_desc_rings(pdata);
 	pdata->port_ops->shutdown(pdata);
+	xgene_enet_delete_desc_rings(pdata);
 	free_netdev(ndev);
 
 	return 0;