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Date: Sun, 11 Jun 2017 15:42:50 +0300
From: <netanel@...zon.com>
To: <davem@...emloft.net>, <netdev@...r.kernel.org>
CC: Netanel Belgazal <netanel@...zon.com>, <dwmw@...zon.com>,
<zorik@...zon.com>, <matua@...zon.com>, <saeedb@...zon.com>,
<msw@...zon.com>, <aliguori@...zon.com>, <nafea@...zon.com>,
<evgenys@...zon.com>
Subject: [PATCH net 8/9] net: ena: bug fix in lost tx packets detection mechanism
From: Netanel Belgazal <netanel@...zon.com>
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 <netanel@...zon.com>
---
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 @@ static void ena_fw_reset_device(struct work_struct *work)
"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;
};
--
2.7.4
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