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net: ifb: support ethtools stats
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With this feature, we can use the ethtools to get tx/rx
queues stats. This patch, introduce the ifb_update_q_stats
helper to update the queues stats, and ifb_q_stats to simplify
the codes.

Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Link: https://lore.kernel.org/r/20211128014631.43627-1-xiangxia.m.yue@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Tonghao Zhang authored and Jakub Kicinski committed Nov 30, 2021
1 parent 09ae03e commit a21ee5b
Showing 1 changed file with 121 additions and 25 deletions.
146 changes: 121 additions & 25 deletions drivers/net/ifb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
#include <linux/init.h>
#include <linux/interrupt.h>
Expand All @@ -36,30 +37,55 @@
#include <net/net_namespace.h>

#define TX_Q_LIMIT 32

struct ifb_q_stats {
u64 packets;
u64 bytes;
struct u64_stats_sync sync;
};

struct ifb_q_private {
struct net_device *dev;
struct tasklet_struct ifb_tasklet;
int tasklet_pending;
int txqnum;
struct sk_buff_head rq;
u64 rx_packets;
u64 rx_bytes;
struct u64_stats_sync rsync;

struct u64_stats_sync tsync;
u64 tx_packets;
u64 tx_bytes;
struct sk_buff_head tq;
struct ifb_q_stats rx_stats;
struct ifb_q_stats tx_stats;
} ____cacheline_aligned_in_smp;

struct ifb_dev_private {
struct ifb_q_private *tx_private;
};

/* For ethtools stats. */
struct ifb_q_stats_desc {
char desc[ETH_GSTRING_LEN];
size_t offset;
};

#define IFB_Q_STAT(m) offsetof(struct ifb_q_stats, m)

static const struct ifb_q_stats_desc ifb_q_stats_desc[] = {
{ "packets", IFB_Q_STAT(packets) },
{ "bytes", IFB_Q_STAT(bytes) },
};

#define IFB_Q_STATS_LEN ARRAY_SIZE(ifb_q_stats_desc)

static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
static int ifb_open(struct net_device *dev);
static int ifb_close(struct net_device *dev);

static void ifb_update_q_stats(struct ifb_q_stats *stats, int len)
{
u64_stats_update_begin(&stats->sync);
stats->packets++;
stats->bytes += len;
u64_stats_update_end(&stats->sync);
}

static void ifb_ri_tasklet(struct tasklet_struct *t)
{
struct ifb_q_private *txp = from_tasklet(txp, t, ifb_tasklet);
Expand All @@ -83,10 +109,7 @@ static void ifb_ri_tasklet(struct tasklet_struct *t)
#endif
nf_skip_egress(skb, true);

u64_stats_update_begin(&txp->tsync);
txp->tx_packets++;
txp->tx_bytes += skb->len;
u64_stats_update_end(&txp->tsync);
ifb_update_q_stats(&txp->tx_stats, skb->len);

rcu_read_lock();
skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif);
Expand Down Expand Up @@ -139,18 +162,18 @@ static void ifb_stats64(struct net_device *dev,

for (i = 0; i < dev->num_tx_queues; i++,txp++) {
do {
start = u64_stats_fetch_begin_irq(&txp->rsync);
packets = txp->rx_packets;
bytes = txp->rx_bytes;
} while (u64_stats_fetch_retry_irq(&txp->rsync, start));
start = u64_stats_fetch_begin_irq(&txp->rx_stats.sync);
packets = txp->rx_stats.packets;
bytes = txp->rx_stats.bytes;
} while (u64_stats_fetch_retry_irq(&txp->rx_stats.sync, start));
stats->rx_packets += packets;
stats->rx_bytes += bytes;

do {
start = u64_stats_fetch_begin_irq(&txp->tsync);
packets = txp->tx_packets;
bytes = txp->tx_bytes;
} while (u64_stats_fetch_retry_irq(&txp->tsync, start));
start = u64_stats_fetch_begin_irq(&txp->tx_stats.sync);
packets = txp->tx_stats.packets;
bytes = txp->tx_stats.bytes;
} while (u64_stats_fetch_retry_irq(&txp->tx_stats.sync, start));
stats->tx_packets += packets;
stats->tx_bytes += bytes;
}
Expand All @@ -173,14 +196,83 @@ static int ifb_dev_init(struct net_device *dev)
txp->dev = dev;
__skb_queue_head_init(&txp->rq);
__skb_queue_head_init(&txp->tq);
u64_stats_init(&txp->rsync);
u64_stats_init(&txp->tsync);
u64_stats_init(&txp->rx_stats.sync);
u64_stats_init(&txp->tx_stats.sync);
tasklet_setup(&txp->ifb_tasklet, ifb_ri_tasklet);
netif_tx_start_queue(netdev_get_tx_queue(dev, i));
}
return 0;
}

static void ifb_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
{
u8 *p = buf;
int i, j;

switch (stringset) {
case ETH_SS_STATS:
for (i = 0; i < dev->real_num_rx_queues; i++)
for (j = 0; j < IFB_Q_STATS_LEN; j++)
ethtool_sprintf(&p, "rx_queue_%u_%.18s",
i, ifb_q_stats_desc[j].desc);

for (i = 0; i < dev->real_num_tx_queues; i++)
for (j = 0; j < IFB_Q_STATS_LEN; j++)
ethtool_sprintf(&p, "tx_queue_%u_%.18s",
i, ifb_q_stats_desc[j].desc);

break;
}
}

static int ifb_get_sset_count(struct net_device *dev, int sset)
{
switch (sset) {
case ETH_SS_STATS:
return IFB_Q_STATS_LEN * (dev->real_num_rx_queues +
dev->real_num_tx_queues);
default:
return -EOPNOTSUPP;
}
}

static void ifb_fill_stats_data(u64 **data,
struct ifb_q_stats *q_stats)
{
void *stats_base = (void *)q_stats;
unsigned int start;
size_t offset;
int j;

do {
start = u64_stats_fetch_begin_irq(&q_stats->sync);
for (j = 0; j < IFB_Q_STATS_LEN; j++) {
offset = ifb_q_stats_desc[j].offset;
(*data)[j] = *(u64 *)(stats_base + offset);
}
} while (u64_stats_fetch_retry_irq(&q_stats->sync, start));

*data += IFB_Q_STATS_LEN;
}

static void ifb_get_ethtool_stats(struct net_device *dev,
struct ethtool_stats *stats, u64 *data)
{
struct ifb_dev_private *dp = netdev_priv(dev);
struct ifb_q_private *txp;
int i;

for (i = 0; i < dev->real_num_rx_queues; i++) {
txp = dp->tx_private + i;
ifb_fill_stats_data(&data, &txp->rx_stats);
}

for (i = 0; i < dev->real_num_tx_queues; i++) {
txp = dp->tx_private + i;
ifb_fill_stats_data(&data, &txp->tx_stats);
}
}

static const struct net_device_ops ifb_netdev_ops = {
.ndo_open = ifb_open,
.ndo_stop = ifb_close,
Expand All @@ -190,6 +282,12 @@ static const struct net_device_ops ifb_netdev_ops = {
.ndo_init = ifb_dev_init,
};

static const struct ethtool_ops ifb_ethtool_ops = {
.get_strings = ifb_get_strings,
.get_sset_count = ifb_get_sset_count,
.get_ethtool_stats = ifb_get_ethtool_stats,
};

#define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_FRAGLIST | \
NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \
Expand All @@ -213,6 +311,7 @@ static void ifb_setup(struct net_device *dev)
{
/* Initialize the device structure. */
dev->netdev_ops = &ifb_netdev_ops;
dev->ethtool_ops = &ifb_ethtool_ops;

/* Fill in device structure with ethernet-generic values. */
ether_setup(dev);
Expand Down Expand Up @@ -241,10 +340,7 @@ static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
struct ifb_dev_private *dp = netdev_priv(dev);
struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);

u64_stats_update_begin(&txp->rsync);
txp->rx_packets++;
txp->rx_bytes += skb->len;
u64_stats_update_end(&txp->rsync);
ifb_update_q_stats(&txp->rx_stats, skb->len);

if (!skb->redirected || !skb->skb_iif) {
dev_kfree_skb(skb);
Expand Down

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