From 800c55cb76be6617232ef50a2be29830f3aa8e5c Mon Sep 17 00:00:00 2001 From: Netanel Belgazal Date: Sun, 11 Jun 2017 15:42:50 +0300 Subject: [PATCH] net: ena: bug fix in lost tx packets detection mechanism check_for_missing_tx_completions() is called from a timer task and looking for lost tx packets. The old implementation accumulate all the lost tx packets and did not check if those packets were retrieved on a later stage. This cause to a situation where the driver reset the device for no reason. Fixes: 1738cd3ed342 ("Add a driver for Amazon Elastic Network Adapters (ENA)") Signed-off-by: Netanel Belgazal Signed-off-by: David S. Miller --- drivers/net/ethernet/amazon/ena/ena_ethtool.c | 1 - drivers/net/ethernet/amazon/ena/ena_netdev.c | 66 +++++++++++-------- drivers/net/ethernet/amazon/ena/ena_netdev.h | 14 +++- 3 files changed, 50 insertions(+), 31 deletions(-) diff --git a/drivers/net/ethernet/amazon/ena/ena_ethtool.c b/drivers/net/ethernet/amazon/ena/ena_ethtool.c index 533b2fbdeef1..3ee55e2fd694 100644 --- a/drivers/net/ethernet/amazon/ena/ena_ethtool.c +++ b/drivers/net/ethernet/amazon/ena/ena_ethtool.c @@ -80,7 +80,6 @@ static const struct ena_stats ena_stats_tx_strings[] = { ENA_STAT_TX_ENTRY(tx_poll), ENA_STAT_TX_ENTRY(doorbells), ENA_STAT_TX_ENTRY(prepare_ctx_err), - ENA_STAT_TX_ENTRY(missing_tx_comp), ENA_STAT_TX_ENTRY(bad_req_id), }; diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c index 3c366bfbbab1..4f16ed38bcf3 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -1995,6 +1995,7 @@ static netdev_tx_t ena_start_xmit(struct sk_buff *skb, struct net_device *dev) tx_info->tx_descs = nb_hw_desc; tx_info->last_jiffies = jiffies; + tx_info->print_once = 0; tx_ring->next_to_use = ENA_TX_RING_IDX_NEXT(next_to_use, tx_ring->ring_size); @@ -2564,13 +2565,44 @@ err: "Reset attempt failed. Can not reset the device\n"); } -static void check_for_missing_tx_completions(struct ena_adapter *adapter) +static int check_missing_comp_in_queue(struct ena_adapter *adapter, + struct ena_ring *tx_ring) { struct ena_tx_buffer *tx_buf; unsigned long last_jiffies; + u32 missed_tx = 0; + int i; + + for (i = 0; i < tx_ring->ring_size; i++) { + tx_buf = &tx_ring->tx_buffer_info[i]; + last_jiffies = tx_buf->last_jiffies; + if (unlikely(last_jiffies && + time_is_before_jiffies(last_jiffies + TX_TIMEOUT))) { + if (!tx_buf->print_once) + netif_notice(adapter, tx_err, adapter->netdev, + "Found a Tx that wasn't completed on time, qid %d, index %d.\n", + tx_ring->qid, i); + + tx_buf->print_once = 1; + missed_tx++; + + if (unlikely(missed_tx > MAX_NUM_OF_TIMEOUTED_PACKETS)) { + netif_err(adapter, tx_err, adapter->netdev, + "The number of lost tx completions is above the threshold (%d > %d). Reset the device\n", + missed_tx, MAX_NUM_OF_TIMEOUTED_PACKETS); + set_bit(ENA_FLAG_TRIGGER_RESET, &adapter->flags); + return -EIO; + } + } + } + + return 0; +} + +static void check_for_missing_tx_completions(struct ena_adapter *adapter) +{ struct ena_ring *tx_ring; - int i, j, budget; - u32 missed_tx; + int i, budget, rc; /* Make sure the driver doesn't turn the device in other process */ smp_rmb(); @@ -2586,31 +2618,9 @@ static void check_for_missing_tx_completions(struct ena_adapter *adapter) for (i = adapter->last_monitored_tx_qid; i < adapter->num_queues; i++) { tx_ring = &adapter->tx_ring[i]; - for (j = 0; j < tx_ring->ring_size; j++) { - tx_buf = &tx_ring->tx_buffer_info[j]; - last_jiffies = tx_buf->last_jiffies; - if (unlikely(last_jiffies && time_is_before_jiffies(last_jiffies + TX_TIMEOUT))) { - netif_notice(adapter, tx_err, adapter->netdev, - "Found a Tx that wasn't completed on time, qid %d, index %d.\n", - tx_ring->qid, j); - - u64_stats_update_begin(&tx_ring->syncp); - missed_tx = tx_ring->tx_stats.missing_tx_comp++; - u64_stats_update_end(&tx_ring->syncp); - - /* Clear last jiffies so the lost buffer won't - * be counted twice. - */ - tx_buf->last_jiffies = 0; - - if (unlikely(missed_tx > MAX_NUM_OF_TIMEOUTED_PACKETS)) { - netif_err(adapter, tx_err, adapter->netdev, - "The number of lost tx completion is above the threshold (%d > %d). Reset the device\n", - missed_tx, MAX_NUM_OF_TIMEOUTED_PACKETS); - set_bit(ENA_FLAG_TRIGGER_RESET, &adapter->flags); - } - } - } + rc = check_missing_comp_in_queue(adapter, tx_ring); + if (unlikely(rc)) + return; budget--; if (!budget) diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.h b/drivers/net/ethernet/amazon/ena/ena_netdev.h index 8828f1d6dd22..88b5e5612338 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.h +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.h @@ -146,7 +146,18 @@ struct ena_tx_buffer { u32 tx_descs; /* num of buffers used by this skb */ u32 num_of_bufs; - /* Save the last jiffies to detect missing tx packets */ + + /* Used for detect missing tx packets to limit the number of prints */ + u32 print_once; + /* Save the last jiffies to detect missing tx packets + * + * sets to non zero value on ena_start_xmit and set to zero on + * napi and timer_Service_routine. + * + * while this value is not protected by lock, + * a given packet is not expected to be handled by ena_start_xmit + * and by napi/timer_service at the same time. + */ unsigned long last_jiffies; struct ena_com_buf bufs[ENA_PKT_MAX_BUFS]; } ____cacheline_aligned; @@ -170,7 +181,6 @@ struct ena_stats_tx { u64 napi_comp; u64 tx_poll; u64 doorbells; - u64 missing_tx_comp; u64 bad_req_id; }; -- 2.30.2