Function hinic_get_stats64() will do two operations:
1. reads stats from every hinic_rxq/txq and accumulates them
2. calls hinic_rxq/txq_clean_stats() to clean every rxq/txq's stats
For hinic_get_stats64(), it could get right data, because it sums all
data to nic_dev->rx_stats/tx_stats.
But it is wrong for get_drv_queue_stats(), this function will read
hinic_rxq's stats, which have been cleared to zero by hinic_get_stats64().
I have observed hinic's cleanup operation by using such command:
> watch -n 1 "cat ethtool -S eth4 | tail -40"
Result before:
...
rxq7_pkts: 1
rxq7_bytes: 90
rxq7_errors: 0
rxq7_csum_errors: 0
rxq7_other_errors: 0
...
rxq9_pkts: 11
rxq9_bytes: 726
rxq9_errors: 0
rxq9_csum_errors: 0
rxq9_other_errors: 0
...
rxq11_pkts: 0
rxq11_bytes: 0
rxq11_errors: 0
rxq11_csum_errors: 0
rxq11_other_errors: 0
Result after a few seconds:
...
rxq7_pkts: 0
rxq7_bytes: 0
rxq7_errors: 0
rxq7_csum_errors: 0
rxq7_other_errors: 0
...
rxq9_pkts: 2
rxq9_bytes: 132
rxq9_errors: 0
rxq9_csum_errors: 0
rxq9_other_errors: 0
...
rxq11_pkts: 1
rxq11_bytes: 170
rxq11_errors: 0
rxq11_csum_errors: 0
rxq11_other_errors: 0
To solve this problem, we just keep every queue's total stats in their own
queue (aka hinic_{rxq|txq}), and simply sum all per-queue stats every time
calling hinic_get_stats64().
With that solution, there is no need to clean per-queue stats now,
and there is no need to maintain global hinic_dev.{tx|rx}_stats, too.
Fixes: edd384f682cc ("net-next/hinic: Add ethtool and stats")
Signed-off-by: Qiao Ma <[email protected]>
Reported-by: kernel test robot <[email protected]>
---
drivers/net/ethernet/huawei/hinic/hinic_dev.h | 3 --
drivers/net/ethernet/huawei/hinic/hinic_main.c | 57 ++++++++------------------
drivers/net/ethernet/huawei/hinic/hinic_rx.c | 2 -
drivers/net/ethernet/huawei/hinic/hinic_tx.c | 2 -
4 files changed, 16 insertions(+), 48 deletions(-)
diff --git a/drivers/net/ethernet/huawei/hinic/hinic_dev.h b/drivers/net/ethernet/huawei/hinic/hinic_dev.h
index fb3e89141a0d..a4fbf44f944c 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_dev.h
+++ b/drivers/net/ethernet/huawei/hinic/hinic_dev.h
@@ -95,9 +95,6 @@ struct hinic_dev {
u16 sq_depth;
u16 rq_depth;
- struct hinic_txq_stats tx_stats;
- struct hinic_rxq_stats rx_stats;
-
u8 rss_tmpl_idx;
u8 rss_hash_engine;
u16 num_rss;
diff --git a/drivers/net/ethernet/huawei/hinic/hinic_main.c b/drivers/net/ethernet/huawei/hinic/hinic_main.c
index 56a89793f47d..89dc52510fdc 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_main.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_main.c
@@ -80,56 +80,44 @@ static int set_features(struct hinic_dev *nic_dev,
netdev_features_t pre_features,
netdev_features_t features, bool force_change);
-static void update_rx_stats(struct hinic_dev *nic_dev, struct hinic_rxq *rxq)
+static void gather_rx_stats(struct hinic_rxq_stats *nic_rx_stats, struct hinic_rxq *rxq)
{
- struct hinic_rxq_stats *nic_rx_stats = &nic_dev->rx_stats;
struct hinic_rxq_stats rx_stats;
- u64_stats_init(&rx_stats.syncp);
-
hinic_rxq_get_stats(rxq, &rx_stats);
- u64_stats_update_begin(&nic_rx_stats->syncp);
nic_rx_stats->bytes += rx_stats.bytes;
nic_rx_stats->pkts += rx_stats.pkts;
nic_rx_stats->errors += rx_stats.errors;
nic_rx_stats->csum_errors += rx_stats.csum_errors;
nic_rx_stats->other_errors += rx_stats.other_errors;
- u64_stats_update_end(&nic_rx_stats->syncp);
-
- hinic_rxq_clean_stats(rxq);
}
-static void update_tx_stats(struct hinic_dev *nic_dev, struct hinic_txq *txq)
+static void gather_tx_stats(struct hinic_txq_stats *nic_tx_stats, struct hinic_txq *txq)
{
- struct hinic_txq_stats *nic_tx_stats = &nic_dev->tx_stats;
struct hinic_txq_stats tx_stats;
- u64_stats_init(&tx_stats.syncp);
-
hinic_txq_get_stats(txq, &tx_stats);
- u64_stats_update_begin(&nic_tx_stats->syncp);
nic_tx_stats->bytes += tx_stats.bytes;
nic_tx_stats->pkts += tx_stats.pkts;
nic_tx_stats->tx_busy += tx_stats.tx_busy;
nic_tx_stats->tx_wake += tx_stats.tx_wake;
nic_tx_stats->tx_dropped += tx_stats.tx_dropped;
nic_tx_stats->big_frags_pkts += tx_stats.big_frags_pkts;
- u64_stats_update_end(&nic_tx_stats->syncp);
-
- hinic_txq_clean_stats(txq);
}
-static void update_nic_stats(struct hinic_dev *nic_dev)
+static void gather_nic_stats(struct hinic_dev *nic_dev,
+ struct hinic_rxq_stats *nic_rx_stats,
+ struct hinic_txq_stats *nic_tx_stats)
{
int i, num_qps = hinic_hwdev_num_qps(nic_dev->hwdev);
for (i = 0; i < num_qps; i++)
- update_rx_stats(nic_dev, &nic_dev->rxqs[i]);
+ gather_rx_stats(nic_rx_stats, &nic_dev->rxqs[i]);
for (i = 0; i < num_qps; i++)
- update_tx_stats(nic_dev, &nic_dev->txqs[i]);
+ gather_tx_stats(nic_tx_stats, &nic_dev->txqs[i]);
}
/**
@@ -558,8 +546,6 @@ int hinic_close(struct net_device *netdev)
netif_carrier_off(netdev);
netif_tx_disable(netdev);
- update_nic_stats(nic_dev);
-
up(&nic_dev->mgmt_lock);
if (!HINIC_IS_VF(nic_dev->hwdev->hwif))
@@ -853,26 +839,23 @@ static void hinic_get_stats64(struct net_device *netdev,
struct rtnl_link_stats64 *stats)
{
struct hinic_dev *nic_dev = netdev_priv(netdev);
- struct hinic_rxq_stats *nic_rx_stats;
- struct hinic_txq_stats *nic_tx_stats;
-
- nic_rx_stats = &nic_dev->rx_stats;
- nic_tx_stats = &nic_dev->tx_stats;
+ struct hinic_rxq_stats nic_rx_stats = {};
+ struct hinic_txq_stats nic_tx_stats = {};
down(&nic_dev->mgmt_lock);
if (nic_dev->flags & HINIC_INTF_UP)
- update_nic_stats(nic_dev);
+ gather_nic_stats(nic_dev, &nic_rx_stats, &nic_tx_stats);
up(&nic_dev->mgmt_lock);
- stats->rx_bytes = nic_rx_stats->bytes;
- stats->rx_packets = nic_rx_stats->pkts;
- stats->rx_errors = nic_rx_stats->errors;
+ stats->rx_bytes = nic_rx_stats.bytes;
+ stats->rx_packets = nic_rx_stats.pkts;
+ stats->rx_errors = nic_rx_stats.errors;
- stats->tx_bytes = nic_tx_stats->bytes;
- stats->tx_packets = nic_tx_stats->pkts;
- stats->tx_errors = nic_tx_stats->tx_dropped;
+ stats->tx_bytes = nic_tx_stats.bytes;
+ stats->tx_packets = nic_tx_stats.pkts;
+ stats->tx_errors = nic_tx_stats.tx_dropped;
}
static int hinic_set_features(struct net_device *netdev,
@@ -1171,8 +1154,6 @@ static void hinic_free_intr_coalesce(struct hinic_dev *nic_dev)
static int nic_dev_init(struct pci_dev *pdev)
{
struct hinic_rx_mode_work *rx_mode_work;
- struct hinic_txq_stats *tx_stats;
- struct hinic_rxq_stats *rx_stats;
struct hinic_dev *nic_dev;
struct net_device *netdev;
struct hinic_hwdev *hwdev;
@@ -1234,12 +1215,6 @@ static int nic_dev_init(struct pci_dev *pdev)
sema_init(&nic_dev->mgmt_lock, 1);
- tx_stats = &nic_dev->tx_stats;
- rx_stats = &nic_dev->rx_stats;
-
- u64_stats_init(&tx_stats->syncp);
- u64_stats_init(&rx_stats->syncp);
-
nic_dev->vlan_bitmap = devm_bitmap_zalloc(&pdev->dev, VLAN_N_VID,
GFP_KERNEL);
if (!nic_dev->vlan_bitmap) {
diff --git a/drivers/net/ethernet/huawei/hinic/hinic_rx.c b/drivers/net/ethernet/huawei/hinic/hinic_rx.c
index 24b7b819dbfb..a866bea65110 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_rx.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_rx.c
@@ -73,7 +73,6 @@ void hinic_rxq_get_stats(struct hinic_rxq *rxq, struct hinic_rxq_stats *stats)
struct hinic_rxq_stats *rxq_stats = &rxq->rxq_stats;
unsigned int start;
- u64_stats_update_begin(&stats->syncp);
do {
start = u64_stats_fetch_begin(&rxq_stats->syncp);
stats->pkts = rxq_stats->pkts;
@@ -83,7 +82,6 @@ void hinic_rxq_get_stats(struct hinic_rxq *rxq, struct hinic_rxq_stats *stats)
stats->csum_errors = rxq_stats->csum_errors;
stats->other_errors = rxq_stats->other_errors;
} while (u64_stats_fetch_retry(&rxq_stats->syncp, start));
- u64_stats_update_end(&stats->syncp);
}
/**
diff --git a/drivers/net/ethernet/huawei/hinic/hinic_tx.c b/drivers/net/ethernet/huawei/hinic/hinic_tx.c
index 87408e7bb809..5051cdff2384 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_tx.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_tx.c
@@ -98,7 +98,6 @@ void hinic_txq_get_stats(struct hinic_txq *txq, struct hinic_txq_stats *stats)
struct hinic_txq_stats *txq_stats = &txq->txq_stats;
unsigned int start;
- u64_stats_update_begin(&stats->syncp);
do {
start = u64_stats_fetch_begin(&txq_stats->syncp);
stats->pkts = txq_stats->pkts;
@@ -108,7 +107,6 @@ void hinic_txq_get_stats(struct hinic_txq *txq, struct hinic_txq_stats *stats)
stats->tx_dropped = txq_stats->tx_dropped;
stats->big_frags_pkts = txq_stats->big_frags_pkts;
} while (u64_stats_fetch_retry(&txq_stats->syncp, start));
- u64_stats_update_end(&stats->syncp);
}
/**
--
1.8.3.1
When using hinic device as a bond slave device, and reading device stats
of master bond device, the kernel may hung.
The kernel panic calltrace as follows:
Kernel panic - not syncing: softlockup: hung tasks
Call trace:
native_queued_spin_lock_slowpath+0x1ec/0x31c
dev_get_stats+0x60/0xcc
dev_seq_printf_stats+0x40/0x120
dev_seq_show+0x1c/0x40
seq_read_iter+0x3c8/0x4dc
seq_read+0xe0/0x130
proc_reg_read+0xa8/0xe0
vfs_read+0xb0/0x1d4
ksys_read+0x70/0xfc
__arm64_sys_read+0x20/0x30
el0_svc_common+0x88/0x234
do_el0_svc+0x2c/0x90
el0_svc+0x1c/0x30
el0_sync_handler+0xa8/0xb0
el0_sync+0x148/0x180
And the calltrace of task that actually caused kernel hungs as follows:
__switch_to+124
__schedule+548
schedule+72
schedule_timeout+348
__down_common+188
__down+24
down+104
hinic_get_stats64+44 [hinic]
dev_get_stats+92
bond_get_stats+172 [bonding]
dev_get_stats+92
dev_seq_printf_stats+60
dev_seq_show+24
seq_read_iter+964
seq_read+220
proc_reg_read+164
vfs_read+172
ksys_read+108
__arm64_sys_read+28
el0_svc_common+132
do_el0_svc+40
el0_svc+24
el0_sync_handler+164
el0_sync+324
When getting device stats from bond, kernel will call bond_get_stats().
It first holds the spinlock bond->stats_lock, and then call
hinic_get_stats64() to collect hinic device's stats.
However, hinic_get_stats64() calls `down(&nic_dev->mgmt_lock)` to
protect its critical section, which may schedule current task out.
And if system is under high pressure, the task cannot be woken up
immediately, which eventually triggers kernel hung panic.
Since previous patch has replaced hinic_dev.tx_stats/rx_stats with local
variable in hinic_get_stats64(), there is nothing need to be protected
by lock, so just removing down()/up() is ok.
Fixes: edd384f682cc ("net-next/hinic: Add ethtool and stats")
Signed-off-by: Qiao Ma <[email protected]>
---
drivers/net/ethernet/huawei/hinic/hinic_main.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/net/ethernet/huawei/hinic/hinic_main.c b/drivers/net/ethernet/huawei/hinic/hinic_main.c
index 89dc52510fdc..c23ee2ddbce3 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_main.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_main.c
@@ -842,13 +842,9 @@ static void hinic_get_stats64(struct net_device *netdev,
struct hinic_rxq_stats nic_rx_stats = {};
struct hinic_txq_stats nic_tx_stats = {};
- down(&nic_dev->mgmt_lock);
-
if (nic_dev->flags & HINIC_INTF_UP)
gather_nic_stats(nic_dev, &nic_rx_stats, &nic_tx_stats);
- up(&nic_dev->mgmt_lock);
-
stats->rx_bytes = nic_rx_stats.bytes;
stats->rx_packets = nic_rx_stats.pkts;
stats->rx_errors = nic_rx_stats.errors;
--
1.8.3.1