[PATCH bpf-next v3 4/7] bpf: use rcu_read_lock_dont_migrate() for bpf_iter_run_prog()

[Menglong Dong]

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 <dong...@chinatelecom.cn>
---
v2:
- use rcu_read_lock_dont_migrate() instead of rcu_migrate_disable()
---
 kernel/bpf/bpf_iter.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 0cbcae727079..6ac35430c573 100644
--- 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:
-- 
2.50.1