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flow_dissector: Pull BPF program assignment up to bpf-netns

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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: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200625141357.910330-2-jakub@cloudflare.com
This commit is contained in:
Jakub Sitnicki 2020-06-25 16:13:54 +02:00 committed by Alexei Starovoitov
parent 517bbe1994
commit 3b7016996c
3 changed files with 22 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
include/net/flow_dissector.h
View file

@ -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

20
kernel/bpf/net_namespace.c
View file

@ -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:

13
net/core/flow_dissector.c
View file

@ -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 */