Commit 3b701699 authored by Jakub Sitnicki's avatar Jakub Sitnicki Committed by Alexei Starovoitov
Browse files

flow_dissector: Pull BPF program assignment up to bpf-netns 



Prepare for using bpf_prog_array to store attached programs by moving out
code that updates the attached program out of flow dissector.

Managing bpf_prog_array is more involved than updating a single bpf_prog
pointer. This will let us do it all from one place, bpf/net_namespace.c, in
the subsequent patch.

No functional change intended.

Signed-off-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200625141357.910330-2-jakub@cloudflare.com
parent 517bbe19

include/net/flow_dissector.h

+2 −1
Original line number Diff line number Diff line
@@ -372,7 +372,8 @@ flow_dissector_init_keys(struct flow_dissector_key_control *key_control, 
}



#ifdef CONFIG_BPF_SYSCALL

int flow_dissector_bpf_prog_attach(struct net *net, struct bpf_prog *prog);

int flow_dissector_bpf_prog_attach_check(struct net *net,

					 struct bpf_prog *prog);

#endif /* CONFIG_BPF_SYSCALL */



#endif

kernel/bpf/net_namespace.c

+18 −2
Original line number Diff line number Diff line
@@ -189,6 +189,7 @@ int netns_bpf_prog_query(const union bpf_attr *attr, 
int netns_bpf_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)

{

	enum netns_bpf_attach_type type;

	struct bpf_prog *attached;

	struct net *net;

	int ret;
@@ -207,12 +208,26 @@ int netns_bpf_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) 


	switch (type) {

	case NETNS_BPF_FLOW_DISSECTOR:

		ret = flow_dissector_bpf_prog_attach(net, prog);

		ret = flow_dissector_bpf_prog_attach_check(net, prog);

		break;

	default:

		ret = -EINVAL;

		break;

	}

	if (ret)

		goto out_unlock;



	attached = rcu_dereference_protected(net->bpf.progs[type],

					     lockdep_is_held(&netns_bpf_mutex));

	if (attached == prog) {

		/* The same program cannot be attached twice */

		ret = -EINVAL;

		goto out_unlock;

	}

	rcu_assign_pointer(net->bpf.progs[type], prog);

	if (attached)

		bpf_prog_put(attached);



out_unlock:

	mutex_unlock(&netns_bpf_mutex);
@@ -277,7 +292,7 @@ static int netns_bpf_link_attach(struct net *net, struct bpf_link *link, 


	switch (type) {

	case NETNS_BPF_FLOW_DISSECTOR:

		err = flow_dissector_bpf_prog_attach(net, link->prog);

		err = flow_dissector_bpf_prog_attach_check(net, link->prog);

		break;

	default:

		err = -EINVAL;
@@ -286,6 +301,7 @@ static int netns_bpf_link_attach(struct net *net, struct bpf_link *link, 
	if (err)

		goto out_unlock;



	rcu_assign_pointer(net->bpf.progs[type], link->prog);

	net->bpf.links[type] = link;



out_unlock:

net/core/flow_dissector.c

+2 −11
Original line number Diff line number Diff line
@@ -70,10 +70,10 @@ void skb_flow_dissector_init(struct flow_dissector *flow_dissector, 
EXPORT_SYMBOL(skb_flow_dissector_init);



#ifdef CONFIG_BPF_SYSCALL

int flow_dissector_bpf_prog_attach(struct net *net, struct bpf_prog *prog)

int flow_dissector_bpf_prog_attach_check(struct net *net,

					 struct bpf_prog *prog)

{

	enum netns_bpf_attach_type type = NETNS_BPF_FLOW_DISSECTOR;

	struct bpf_prog *attached;



	if (net == &init_net) {

		/* BPF flow dissector in the root namespace overrides
@@ -97,15 +97,6 @@ int flow_dissector_bpf_prog_attach(struct net *net, struct bpf_prog *prog) 
			return -EEXIST;

	}



	attached = rcu_dereference_protected(net->bpf.progs[type],

					     lockdep_is_held(&netns_bpf_mutex));

	if (attached == prog)

		/* The same program cannot be attached twice */

		return -EINVAL;



	rcu_assign_pointer(net->bpf.progs[type], prog);

	if (attached)

		bpf_prog_put(attached);

	return 0;

}

#endif /* CONFIG_BPF_SYSCALL */

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