netdev - [PATCH v3 net-next 06/11] ibmvnic: Clean up tx pools when closing

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Message-Id: <20170502185247.28214.70469.stgit@ltcalpine2-lp23.aus.stglabs.ibm.com>
Date:   Tue, 02 May 2017 14:52:47 -0400
From:   Nathan Fontenot <nfont@...ux.vnet.ibm.com>
To:     netdev@...r.kernel.org
Cc:     brking@...ux.vnet.ibm.com, jallen@...ux.vnet.ibm.com,
        muvic@...ux.vnet.ibm.com, tlfalcon@...ux.vnet.ibm.com
Subject: [PATCH v3 net-next 06/11] ibmvnic: Clean up tx pools when closing

When closing the ibmvnic driver, most notably during the reset
path, the tx pools need to be cleaned to ensure there are no
hanging skbs that need to be free'ed.

The need for this was found during debugging a loss of network
traffic after handling a driver reset. The underlying cause was
some skbs in the tx pool that were never free'ed. As a
result the upper network layers never tried a re-send since it
believed the driver still had the skb.

Signed-off-by: Nathan Fontenot <nfont@...ux.vnet.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c |   30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index d20d884..0400ae7 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -760,6 +760,34 @@ static void disable_sub_crqs(struct ibmvnic_adapter *adapter)
 	}
 }
 
+static void clean_tx_pools(struct ibmvnic_adapter *adapter)
+{
+	struct ibmvnic_tx_pool *tx_pool;
+	u64 tx_entries;
+	int tx_scrqs;
+	int i, j;
+
+	if (!adapter->tx_pool)
+		return;
+
+	tx_scrqs = be32_to_cpu(adapter->login_rsp_buf->num_txsubm_subcrqs);
+	tx_entries = adapter->req_tx_entries_per_subcrq;
+
+	/* Free any remaining skbs in the tx buffer pools */
+	for (i = 0; i < tx_scrqs; i++) {
+		tx_pool = &adapter->tx_pool[i];
+		if (!tx_pool)
+			continue;
+
+		for (j = 0; j < tx_entries; j++) {
+			if (tx_pool->tx_buff[j].skb) {
+				dev_kfree_skb_any(tx_pool->tx_buff[j].skb);
+				tx_pool->tx_buff[j].skb = NULL;
+			}
+		}
+	}
+}
+
 static int __ibmvnic_close(struct net_device *netdev)
 {
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
@@ -768,6 +796,8 @@ static int __ibmvnic_close(struct net_device *netdev)
 
 	adapter->state = VNIC_CLOSING;
 	netif_tx_stop_all_queues(netdev);
+
+	clean_tx_pools(adapter);
 	disable_sub_crqs(adapter);
 
 	if (adapter->napi) {