drop_monitor: Convert to using devlink tracepoint

Convert drop monitor to use the recently introduced
'devlink_trap_report' tracepoint instead of having devlink call into
drop monitor.

This is both consistent with software originated drops ('kfree_skb'
tracepoint) and also allows drop monitor to be built as a module and
still report hardware originated drops.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/MAINTAINERS b/MAINTAINERS
index 42c69d2..c1e9466 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12065,7 +12065,6 @@ M:      Neil Horman <nhorman@tuxdriver.com>
 L:     netdev@vger.kernel.org
 S:     Maintained
 W:     https://fedorahosted.org/dropwatch/
-F:     include/net/drop_monitor.h
 F:     include/uapi/linux/net_dropmon.h
 F:     net/core/drop_monitor.c
 

diff --git a/include/net/drop_monitor.h b/include/net/drop_monitor.h
deleted file mode 100644 (file)
index 3f5b6dd..0000000
--- a/include/net/drop_monitor.h
+++ /dev/null
@@ -1,36 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-
-#ifndef _NET_DROP_MONITOR_H_
-#define _NET_DROP_MONITOR_H_
-
-#include <linux/ktime.h>
-#include <linux/netdevice.h>
-#include <linux/skbuff.h>
-#include <net/flow_offload.h>
-
-/**
- * struct net_dm_hw_metadata - Hardware-supplied packet metadata.
- * @trap_group_name: Hardware trap group name.
- * @trap_name: Hardware trap name.
- * @input_dev: Input netdevice.
- * @fa_cookie: Flow action user cookie.
- */
-struct net_dm_hw_metadata {
-       const char *trap_group_name;
-       const char *trap_name;
-       struct net_device *input_dev;
-       const struct flow_action_cookie *fa_cookie;
-};
-
-#if IS_REACHABLE(CONFIG_NET_DROP_MONITOR)
-void net_dm_hw_report(struct sk_buff *skb,
-                     const struct net_dm_hw_metadata *hw_metadata);
-#else
-static inline void
-net_dm_hw_report(struct sk_buff *skb,
-                const struct net_dm_hw_metadata *hw_metadata)
-{
-}
-#endif
-
-#endif /* _NET_DROP_MONITOR_H_ */

diff --git a/net/Kconfig b/net/Kconfig
index 3831206..d656716 100644 (file)
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -434,7 +434,6 @@ config NET_SOCK_MSG
 config NET_DEVLINK
        bool
        default n
-       imply NET_DROP_MONITOR
 
 config PAGE_POOL
        bool

diff --git a/net/core/devlink.c b/net/core/devlink.c
index c0f3005..2ea9fdc 100644 (file)
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -27,7 +27,6 @@
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/devlink.h>
-#include <net/drop_monitor.h>
 #define CREATE_TRACE_POINTS
 #include <trace/events/devlink.h>
 
@@ -9261,24 +9260,6 @@ devlink_trap_stats_update(struct devlink_stats __percpu *trap_stats,
        u64_stats_update_end(&stats->syncp);
 }
 
-static void
-devlink_trap_report_metadata_fill(struct net_dm_hw_metadata *hw_metadata,
-                                 const struct devlink_trap_item *trap_item,
-                                 struct devlink_port *in_devlink_port,
-                                 const struct flow_action_cookie *fa_cookie)
-{
-       struct devlink_trap_group_item *group_item = trap_item->group_item;
-
-       hw_metadata->trap_group_name = group_item->group->name;
-       hw_metadata->trap_name = trap_item->trap->name;
-       hw_metadata->fa_cookie = fa_cookie;
-
-       spin_lock(&in_devlink_port->type_lock);
-       if (in_devlink_port->type == DEVLINK_PORT_TYPE_ETH)
-               hw_metadata->input_dev = in_devlink_port->type_dev;
-       spin_unlock(&in_devlink_port->type_lock);
-}
-
 static void
 devlink_trap_report_metadata_set(struct devlink_trap_metadata *metadata,
                                 const struct devlink_trap_item *trap_item,
@@ -9309,7 +9290,6 @@ void devlink_trap_report(struct devlink *devlink, struct sk_buff *skb,
 
 {
        struct devlink_trap_item *trap_item = trap_ctx;
-       struct net_dm_hw_metadata hw_metadata = {};
 
        devlink_trap_stats_update(trap_item->stats, skb->len);
        devlink_trap_stats_update(trap_item->group_item->stats, skb->len);
@@ -9321,10 +9301,6 @@ void devlink_trap_report(struct devlink *devlink, struct sk_buff *skb,
        if (trap_item->trap->type == DEVLINK_TRAP_TYPE_CONTROL)
                return;
 
-       devlink_trap_report_metadata_fill(&hw_metadata, trap_item,
-                                         in_devlink_port, fa_cookie);
-       net_dm_hw_report(skb, &hw_metadata);
-
        if (trace_devlink_trap_report_enabled()) {
                struct devlink_trap_metadata metadata = {};
 

diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 03aba58..c14278f 100644 (file)
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -26,7 +26,6 @@
 #include <linux/bitops.h>
 #include <linux/slab.h>
 #include <linux/module.h>
-#include <net/drop_monitor.h>
 #include <net/genetlink.h>
 #include <net/netevent.h>
 #include <net/flow_offload.h>
@@ -34,6 +33,7 @@
 
 #include <trace/events/skb.h>
 #include <trace/events/napi.h>
+#include <trace/events/devlink.h>
 
 #include <asm/unaligned.h>
 
@@ -108,6 +108,13 @@ static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
 static u32 net_dm_trunc_len;
 static u32 net_dm_queue_len = 1000;
 
+struct net_dm_hw_metadata {
+       const char *trap_group_name;
+       const char *trap_name;
+       struct net_device *input_dev;
+       const struct flow_action_cookie *fa_cookie;
+};
+
 struct net_dm_alert_ops {
        void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
                                void *location);
@@ -1129,25 +1136,32 @@ static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
        [NET_DM_ALERT_MODE_PACKET]      = &net_dm_alert_packet_ops,
 };
 
-void net_dm_hw_report(struct sk_buff *skb,
-                     const struct net_dm_hw_metadata *hw_metadata)
+#if IS_ENABLED(CONFIG_NET_DEVLINK)
+static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
 {
-       rcu_read_lock();
-
-       if (!monitor_hw)
-               goto out;
+       return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
+}
 
-       net_dm_alert_ops_arr[net_dm_alert_mode]->hw_probe(skb, hw_metadata);
+static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
+{
+       unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
+       tracepoint_synchronize_unregister();
+}
+#else
+static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
+{
+       return -EOPNOTSUPP;
+}
 
-out:
-       rcu_read_unlock();
+static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
+{
 }
-EXPORT_SYMBOL_GPL(net_dm_hw_report);
+#endif
 
 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
 {
        const struct net_dm_alert_ops *ops;
-       int cpu;
+       int cpu, rc;
 
        if (monitor_hw) {
                NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
@@ -1171,13 +1185,24 @@ static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
                kfree(hw_entries);
        }
 
+       rc = net_dm_hw_probe_register(ops);
+       if (rc) {
+               NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint");
+               goto err_module_put;
+       }
+
        monitor_hw = true;
 
        return 0;
+
+err_module_put:
+       module_put(THIS_MODULE);
+       return rc;
 }
 
 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
 {
+       const struct net_dm_alert_ops *ops;
        int cpu;
 
        if (!monitor_hw) {
@@ -1185,12 +1210,11 @@ static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
                return;
        }
 
+       ops = net_dm_alert_ops_arr[net_dm_alert_mode];
+
        monitor_hw = false;
 
-       /* After this call returns we are guaranteed that no CPU is processing
-        * any hardware drops.
-        */
-       synchronize_rcu();
+       net_dm_hw_probe_unregister(ops);
 
        for_each_possible_cpu(cpu) {
                struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);