From 86b61a5f2e39bbee254aa4d2c5445059c7656f98 Mon Sep 17 00:00:00 2001 From: Thomas Falcon Date: Fri, 16 Mar 2018 20:00:29 -0500 Subject: [PATCH] ibmvnic: Improve TX buffer accounting Improve TX pool buffer accounting to prevent the producer index from overruning the consumer. First, set the next free index to an invalid value if it is in use. If next buffer to be consumed is in use, drop the packet. Finally, if the transmit fails for some other reason, roll back the consumer index and set the free map entry to its original value. This should also be done if the DMA map fails. Signed-off-by: Thomas Falcon Signed-off-by: David S. Miller --- drivers/net/ethernet/ibm/ibmvnic.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c index 672e922..af6f819 100644 --- a/drivers/net/ethernet/ibm/ibmvnic.c +++ b/drivers/net/ethernet/ibm/ibmvnic.c @@ -1426,6 +1426,16 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) index = tx_pool->free_map[tx_pool->consumer_index]; + if (index == IBMVNIC_INVALID_MAP) { + dev_kfree_skb_any(skb); + tx_send_failed++; + tx_dropped++; + ret = NETDEV_TX_OK; + goto out; + } + + tx_pool->free_map[tx_pool->consumer_index] = IBMVNIC_INVALID_MAP; + offset = index * tx_pool->buf_size; dst = tx_pool->long_term_buff.buff + offset; memset(dst, 0, tx_pool->buf_size); @@ -1522,7 +1532,7 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) tx_map_failed++; tx_dropped++; ret = NETDEV_TX_OK; - goto out; + goto tx_err_out; } lpar_rc = send_subcrq_indirect(adapter, handle_array[queue_num], (u64)tx_buff->indir_dma, @@ -1534,13 +1544,6 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) } if (lpar_rc != H_SUCCESS) { dev_err(dev, "tx failed with code %ld\n", lpar_rc); - - if (tx_pool->consumer_index == 0) - tx_pool->consumer_index = - tx_pool->num_buffers - 1; - else - tx_pool->consumer_index--; - dev_kfree_skb_any(skb); tx_buff->skb = NULL; @@ -1556,7 +1559,7 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) tx_send_failed++; tx_dropped++; ret = NETDEV_TX_OK; - goto out; + goto tx_err_out; } if (atomic_add_return(num_entries, &tx_scrq->used) @@ -1569,7 +1572,16 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) tx_bytes += skb->len; txq->trans_start = jiffies; ret = NETDEV_TX_OK; + goto out; +tx_err_out: + /* roll back consumer index and map array*/ + if (tx_pool->consumer_index == 0) + tx_pool->consumer_index = + tx_pool->num_buffers - 1; + else + tx_pool->consumer_index--; + tx_pool->free_map[tx_pool->consumer_index] = index; out: netdev->stats.tx_dropped += tx_dropped; netdev->stats.tx_bytes += tx_bytes; -- 2.7.4