[PATCH v3 7/7] [not for merge] netstats: example use of stats_fs API

Emanuele Giuseppe Esposito
2020-05-26T11:05:56Z

Apply stats_fs on the networking statistics subsystem.

Currently it only works with disabled network namespace
(CONFIG_NET_NS=n), because multiple namespaces will have the same
device name under the same root source that will cause a conflict in
stats_fs.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
include/linux/netdevice.h | 2 ++
net/Kconfig | 1 +
net/core/dev.c | 66 +++++++++++++++++++++++++++++++++++++++
3 files changed, 69 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 130a668049ab..408c4e7b0e21 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -48,6 +48,7 @@
#include <uapi/linux/if_bonding.h>
#include <uapi/linux/pkt_cls.h>
#include <linux/hashtable.h>
+#include <linux/stats_fs.h>

struct netpoll_info;
struct device;
@@ -2117,6 +2118,7 @@ struct net_device {
unsigned wol_enabled:1;

struct list_head net_notifier_list;
+ struct stats_fs_source *stats_fs_src;

#if IS_ENABLED(CONFIG_MACSEC)
/* MACsec management functions */
diff --git a/net/Kconfig b/net/Kconfig
index df8d8c9bd021..3441d5bb6107 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -8,6 +8,7 @@ menuconfig NET
select NLATTR
select GENERIC_NET_UTILS
select BPF
+ select STATS_FS_API
---help---
Unless you really know what you are doing, you should say Y here.
The reason is that some programs need kernel networking support even
diff --git a/net/core/dev.c b/net/core/dev.c
index 522288177bbd..3db48cd1a097 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -142,6 +142,7 @@
#include <linux/net_namespace.h>
#include <linux/indirect_call_wrapper.h>
#include <net/devlink.h>
+#include <linux/stats_fs.h>

#include "net-sysfs.h"

@@ -150,6 +151,11 @@
/* This should be increased if a protocol with a bigger head is added. */
#define GRO_MAX_HEAD (MAX_HEADER + 128)

+#define NETDEV_STAT(str, m, ...) \
+ { str, offsetof(struct rtnl_link_stats64, m), \
+ &stats_fs_type_netdev_u64, \
+ STATS_FS_SUM, ## __VA_ARGS__ }
+
static DEFINE_SPINLOCK(ptype_lock);
static DEFINE_SPINLOCK(offload_lock);
struct list_head ptype_base[PTYPE_HASH_SIZE] __read_mostly;
@@ -196,6 +202,53 @@ static DEFINE_READ_MOSTLY_HASHTABLE(napi_hash, 8);

static seqcount_t devnet_rename_seq;

+static uint64_t stats_fs_get_netdev_u64(struct stats_fs_value *val,
+ void *base)
+{
+ struct net_device *netdev = (struct net_device *)base;
+ struct rtnl_link_stats64 net_stats;
+
+ dev_get_stats(netdev, &net_stats);
+
+ return stats_fs_get_u64(val, &net_stats);
+}
+
+static struct stats_fs_type stats_fs_type_netdev_u64 = {
+ .get = stats_fs_get_netdev_u64,
+ .clear = NULL,
+ .sign = false
+};
+
+static struct stats_fs_source *netdev_root;
+
+static struct stats_fs_value stats_fs_netdev_entries[] = {
+ NETDEV_STAT("rx_packets", rx_packets),
+ NETDEV_STAT("tx_packets", tx_packets),
+ NETDEV_STAT("rx_bytes", rx_bytes),
+ NETDEV_STAT("tx_bytes", tx_bytes),
+ NETDEV_STAT("rx_errors", rx_errors),
+ NETDEV_STAT("tx_errors", tx_errors),
+ NETDEV_STAT("rx_dropped", rx_dropped),
+ NETDEV_STAT("tx_dropped", tx_dropped),
+ NETDEV_STAT("multicast", multicast),
+ NETDEV_STAT("collisions", collisions),
+ NETDEV_STAT("rx_length_errors", rx_length_errors),
+ NETDEV_STAT("rx_over_errors", rx_over_errors),
+ NETDEV_STAT("rx_crc_errors", rx_crc_errors),
+ NETDEV_STAT("rx_frame_errors", rx_frame_errors),
+ NETDEV_STAT("rx_fifo_errors", rx_fifo_errors),
+ NETDEV_STAT("rx_missed_errors", rx_missed_errors),
+ NETDEV_STAT("tx_aborted_errors", tx_aborted_errors),
+ NETDEV_STAT("tx_carrier_errors", tx_carrier_errors),
+ NETDEV_STAT("tx_fifo_errors", tx_fifo_errors),
+ NETDEV_STAT("tx_heartbeat_errors", tx_heartbeat_errors),
+ NETDEV_STAT("tx_window_errors", tx_window_errors),
+ NETDEV_STAT("rx_compressed", rx_compressed),
+ NETDEV_STAT("tx_compressed", tx_compressed),
+ NETDEV_STAT("rx_nohandler", rx_nohandler),
+ { NULL }
+};
+
static inline void dev_base_seq_inc(struct net *net)
{
while (++net->dev_base_seq == 0)
@@ -8783,6 +8836,11 @@ static void rollback_registered_many(struct list_head *head)
ASSERT_RTNL();

list_for_each_entry_safe(dev, tmp, head, unreg_list) {
+ stats_fs_source_remove_subordinate(netdev_root,
+ dev->stats_fs_src);
+ stats_fs_source_revoke(dev->stats_fs_src);
+ stats_fs_source_put(dev->stats_fs_src);
+
/* Some devices call without registering
* for initialization unwind. Remove those
* devices and proceed with the remaining.
@@ -9436,6 +9494,11 @@ int register_netdevice(struct net_device *dev)
dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U, GFP_KERNEL);

+ dev->stats_fs_src = stats_fs_source_create(0, dev->name);
+ stats_fs_source_add_subordinate(netdev_root, dev->stats_fs_src);
+ stats_fs_source_add_values(dev->stats_fs_src, stats_fs_netdev_entries,
+ dev, 0);
+
out:
return ret;

@@ -10500,6 +10563,9 @@ static int __init net_dev_init(void)
if (netdev_kobject_init())
goto out;

+ netdev_root = stats_fs_source_create(0, "net");
+ stats_fs_source_register(netdev_root);
+
INIT_LIST_HEAD(&ptype_all);
for (i = 0; i < PTYPE_HASH_SIZE; i++)
INIT_LIST_HEAD(&ptype_base[i]);
--
2.25.4