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bpf: offload: allow netdev to disappear while verifier is running

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To allow verifier instruction callbacks without any extra locking
NETDEV_UNREGISTER notification would wait on a waitqueue for verifier
to finish.  This design decision was made when rtnl lock was providing
all the locking.  Use the read/write lock instead and remove the
workqueue.

Verifier will now call into the offload code, so dev_ops are moved
to offload structure.  Since verifier calls are all under
bpf_prog_is_dev_bound() we no longer need static inline implementations
to please builds with CONFIG_NET=n.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Jakub Kicinski
2017-12-27 18:39:05 -08:00
committed by Daniel Borkmann
parent 9a18eedb14
commit cae1927c0b
8 changed files with 37 additions and 48 deletions
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30
kernel/bpf/offload.c
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@@ -44,7 +44,6 @@ int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
return -ENOMEM;
offload->prog = prog;
init_waitqueue_head(&offload->verifier_done);
offload->netdev = dev_get_by_index(current->nsproxy->net_ns,
attr->prog_ifindex);
@@ -97,15 +96,28 @@ int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env)
if (err)
goto exit_unlock;
env->dev_ops = data.verifier.ops;
env->prog->aux->offload->dev_ops = data.verifier.ops;
env->prog->aux->offload->dev_state = true;
env->prog->aux->offload->verifier_running = true;
exit_unlock:
rtnl_unlock();
return err;
}
int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
int insn_idx, int prev_insn_idx)
{
struct bpf_dev_offload *offload;
int ret = -ENODEV;
down_read(&bpf_devs_lock);
offload = env->prog->aux->offload;
if (offload->netdev)
ret = offload->dev_ops->insn_hook(env, insn_idx, prev_insn_idx);
up_read(&bpf_devs_lock);
return ret;
}
static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
{
struct bpf_dev_offload *offload = prog->aux->offload;
@@ -117,9 +129,6 @@ static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
data.offload.prog = prog;
if (offload->verifier_running)
wait_event(offload->verifier_done, !offload->verifier_running);
if (offload->dev_state)
WARN_ON(__bpf_offload_ndo(prog, BPF_OFFLOAD_DESTROY, &data));
@@ -132,9 +141,6 @@ void bpf_prog_offload_destroy(struct bpf_prog *prog)
{
struct bpf_dev_offload *offload = prog->aux->offload;
offload->verifier_running = false;
wake_up(&offload->verifier_done);
rtnl_lock();
down_write(&bpf_devs_lock);
__bpf_prog_offload_destroy(prog);
@@ -146,15 +152,11 @@ void bpf_prog_offload_destroy(struct bpf_prog *prog)
static int bpf_prog_offload_translate(struct bpf_prog *prog)
{
struct bpf_dev_offload *offload = prog->aux->offload;
struct netdev_bpf data = {};
int ret;
data.offload.prog = prog;
offload->verifier_running = false;
wake_up(&offload->verifier_done);
rtnl_lock();
ret = __bpf_offload_ndo(prog, BPF_OFFLOAD_TRANSLATE, &data);
rtnl_unlock();