From: Menglong Dong <menglong8.dong@gmail.com>
Date: Thu, 21 Aug 2025 09:06:06 +0000 (+0800)
Subject: bpf: use rcu_read_lock_dont_migrate() for bpf_iter_run_prog()
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=68748f0397a356122bf9cf33ef77cabbff9c3e51;p=users%2Fhch%2Fmisc.git

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 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: