bpf: use rcu_read_lock_dont_migrate() for bpf_iter_run_prog()

Use rcu_read_lock_dont_migrate() and rcu_read_unlock_migrate() in
bpf_iter_run_prog to obtain better performance when PREEMPT_RCU is
not enabled.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20250821090609.42508-5-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 0cbcae7..6ac3543 100644 (file)
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -705,13 +705,11 @@ int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx)
                migrate_enable();
                rcu_read_unlock_trace();
        } else {
-               rcu_read_lock();
-               migrate_disable();
+               rcu_read_lock_dont_migrate();
                old_run_ctx = bpf_set_run_ctx(&run_ctx);
                ret = bpf_prog_run(prog, ctx);
                bpf_reset_run_ctx(old_run_ctx);
-               migrate_enable();
-               rcu_read_unlock();
+               rcu_read_unlock_migrate();
        }
 
        /* bpf program can only return 0 or 1: