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 <ja...@cloudflare.com>
---
include/net/flow_dissector.h | 3 ++-
kernel/bpf/net_namespace.c | 20 ++++++++++++++++++--
net/core/flow_dissector.c | 13 ++-----------
3 files changed, 22 insertions(+), 14 deletions(-)
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index a7eba43fe4e4..4b6e36288ddd 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -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
diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c
index 78cf061f8179..b951dab2687f 100644
--- a/kernel/bpf/net_namespace.c
+++ b/kernel/bpf/net_namespace.c
@@ -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:
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index d02df0b6d0d9..b57fb1359395 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -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 */
--
2.25.4
