bpf: Use bpf_prog_run_pin_on_cpu() at simple call sites.
All of these cases are strictly of the form:
preempt_disable();
BPF_PROG_RUN(...);
preempt_enable();
Replace this with bpf_prog_run_pin_on_cpu() which wraps BPF_PROG_RUN()
with:
migrate_disable();
BPF_PROG_RUN(...);
migrate_enable();
On non RT enabled kernels this maps to preempt_disable/enable() and on RT
enabled kernels this solely prevents migration, which is sufficient as
there is no requirement to prevent reentrancy to any BPF program from a
preempting task. The only requirement is that the program stays on the same
CPU.
Therefore, this is a trivially correct transformation.
The seccomp loop does not need protection over the loop. It only needs
protection per BPF filter program
[ tglx: Converted to bpf_prog_run_pin_on_cpu() ]
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145643.691493094@linutronix.de
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index a1670df..3eff848 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -920,9 +920,7 @@ bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx,
(int)FLOW_DISSECTOR_F_STOP_AT_ENCAP);
flow_keys->flags = flags;
- preempt_disable();
- result = BPF_PROG_RUN(prog, ctx);
- preempt_enable();
+ result = bpf_prog_run_pin_on_cpu(prog, ctx);
flow_keys->nhoff = clamp_t(u16, flow_keys->nhoff, nhoff, hlen);
flow_keys->thoff = clamp_t(u16, flow_keys->thoff,
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index eeb28cb..c479372 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -628,7 +628,6 @@ int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
struct bpf_prog *prog;
int ret;
- preempt_disable();
rcu_read_lock();
prog = READ_ONCE(psock->progs.msg_parser);
if (unlikely(!prog)) {
@@ -638,7 +637,7 @@ int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
sk_msg_compute_data_pointers(msg);
msg->sk = sk;
- ret = BPF_PROG_RUN(prog, msg);
+ ret = bpf_prog_run_pin_on_cpu(prog, msg);
ret = sk_psock_map_verd(ret, msg->sk_redir);
psock->apply_bytes = msg->apply_bytes;
if (ret == __SK_REDIRECT) {
@@ -653,7 +652,6 @@ int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
}
out:
rcu_read_unlock();
- preempt_enable();
return ret;
}
EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
@@ -665,9 +663,7 @@ static int sk_psock_bpf_run(struct sk_psock *psock, struct bpf_prog *prog,
skb->sk = psock->sk;
bpf_compute_data_end_sk_skb(skb);
- preempt_disable();
- ret = BPF_PROG_RUN(prog, skb);
- preempt_enable();
+ ret = bpf_prog_run_pin_on_cpu(prog, skb);
/* strparser clones the skb before handing it to a upper layer,
* meaning skb_orphan has been called. We NULL sk on the way out
* to ensure we don't trigger a BUG_ON() in skb/sk operations
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index ea9e734..56fac24 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -380,9 +380,7 @@ static int kcm_parse_func_strparser(struct strparser *strp, struct sk_buff *skb)
struct bpf_prog *prog = psock->bpf_prog;
int res;
- preempt_disable();
- res = BPF_PROG_RUN(prog, skb);
- preempt_enable();
+ res = bpf_prog_run_pin_on_cpu(prog, skb);
return res;
}
