[PATCH net-next v2] net: psample: Introduce stubs to remove NIC driver dependency
From: Chris Mi <hidden>
Date: 2021-01-27 07:55:49
In order to send sampled packets to userspace, NIC driver calls psample api directly. But it creates a hard dependency on module psample. Introduce psample_ops to remove the hard dependency. It is initialized when psample module is loaded and set to NULL when the module is unloaded. Reported-by: kernel test robot <redacted> Signed-off-by: Chris Mi <redacted> Reviewed-by: Jiri Pirko <redacted> --- v1->v2: - fix sparse errors include/net/psample.h | 27 +++++++++++++++++++++++++++ net/psample/psample.c | 13 ++++++++++++- net/sched/Makefile | 2 +- net/sched/psample_stub.c | 7 +++++++ 4 files changed, 47 insertions(+), 2 deletions(-) create mode 100644 net/sched/psample_stub.c
diff --git a/include/net/psample.h b/include/net/psample.h
index 68ae16bb0a4a..e6a73128de59 100644
--- a/include/net/psample.h
+++ b/include/net/psample.h@@ -4,6 +4,7 @@ #include <uapi/linux/psample.h> #include <linux/list.h> +#include <linux/skbuff.h> struct psample_group { struct list_head list;
@@ -14,6 +15,15 @@ struct psample_group { struct rcu_head rcu; }; +struct psample_ops { + void (*sample_packet)(struct psample_group *group, struct sk_buff *skb, + u32 trunc_size, int in_ifindex, int out_ifindex, + u32 sample_rate); + +}; + +extern const struct psample_ops __rcu *psample_ops __read_mostly; + struct psample_group *psample_group_get(struct net *net, u32 group_num); void psample_group_take(struct psample_group *group); void psample_group_put(struct psample_group *group);
@@ -35,4 +45,21 @@ static inline void psample_sample_packet(struct psample_group *group, #endif +static inline void +psample_nic_sample_packet(struct psample_group *group, + struct sk_buff *skb, u32 trunc_size, + int in_ifindex, int out_ifindex, + u32 sample_rate) +{ + const struct psample_ops *ops; + + rcu_read_lock(); + ops = rcu_dereference(psample_ops); + if (ops) + psample_ops->sample_packet(group, skb, trunc_size, + in_ifindex, out_ifindex, + sample_rate); + rcu_read_unlock(); +} + #endif /* __NET_PSAMPLE_H */
diff --git a/net/psample/psample.c b/net/psample/psample.c
index 33e238c965bd..2a9fbfe09395 100644
--- a/net/psample/psample.c
+++ b/net/psample/psample.c@@ -8,6 +8,7 @@ #include <linux/kernel.h> #include <linux/skbuff.h> #include <linux/module.h> +#include <linux/rcupdate.h> #include <net/net_namespace.h> #include <net/sock.h> #include <net/netlink.h>
@@ -35,6 +36,10 @@ static const struct genl_multicast_group psample_nl_mcgrps[] = { static struct genl_family psample_nl_family __ro_after_init; +static const struct psample_ops psample_sample_ops = { + .sample_packet = psample_sample_packet, +}; + static int psample_group_nl_fill(struct sk_buff *msg, struct psample_group *group, enum psample_command cmd, u32 portid, u32 seq,
@@ -456,11 +461,17 @@ EXPORT_SYMBOL_GPL(psample_sample_packet); static int __init psample_module_init(void) { - return genl_register_family(&psample_nl_family); + int ret; + + ret = genl_register_family(&psample_nl_family); + if (!ret) + RCU_INIT_POINTER(psample_ops, &psample_sample_ops); + return ret; } static void __exit psample_module_exit(void) { + RCU_INIT_POINTER(psample_ops, NULL); genl_unregister_family(&psample_nl_family); }
diff --git a/net/sched/Makefile b/net/sched/Makefile
index dd14ef413fda..0d92bb98bb26 100644
--- a/net/sched/Makefile
+++ b/net/sched/Makefile@@ -3,7 +3,7 @@ # Makefile for the Linux Traffic Control Unit. # -obj-y := sch_generic.o sch_mq.o +obj-y := sch_generic.o sch_mq.o psample_stub.o obj-$(CONFIG_INET) += sch_frag.o obj-$(CONFIG_NET_SCHED) += sch_api.o sch_blackhole.o
diff --git a/net/sched/psample_stub.c b/net/sched/psample_stub.c
new file mode 100644
index 000000000000..0615a7b64000
--- /dev/null
+++ b/net/sched/psample_stub.c@@ -0,0 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +/* Copyright (c) 2021 Mellanox Technologies. */ + +#include <net/psample.h> + +const struct psample_ops __rcu *psample_ops __read_mostly; +EXPORT_SYMBOL_GPL(psample_ops);
--
2.26.2