lwt_bpf: Replace preempt_disable() with migrate_disable()

migrate_disable() is just a wrapper for preempt_disable() in
non-RT kernel. It is safe to replace it, and RT kernel will
benefit.

Note that it is introduced since Feb 2020.

Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201205075946.497763-2-xiyou.wangcong@gmail.com

diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c
index 4f3cb7c..2f7940b 100644 (file)
--- a/net/core/lwt_bpf.c
+++ b/net/core/lwt_bpf.c
@@ -39,10 +39,10 @@ static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt,
 {
        int ret;
 
-       /* Preempt disable and BH disable are needed to protect per-cpu
+       /* Migration disable and BH disable are needed to protect per-cpu
         * redirect_info between BPF prog and skb_do_redirect().
         */
-       preempt_disable();
+       migrate_disable();
        local_bh_disable();
        bpf_compute_data_pointers(skb);
        ret = bpf_prog_run_save_cb(lwt->prog, skb);
@@ -78,7 +78,7 @@ static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt,
        }
 
        local_bh_enable();
-       preempt_enable();
+       migrate_enable();
 
        return ret;
 }