From: Menglong Dong <menglong8.dong@gmail.com>
Date: Thu, 21 Aug 2025 09:06:04 +0000 (+0800)
Subject: bpf: use rcu_read_lock_dont_migrate() for bpf_cgrp_storage_free()
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=8c0afc7c9c112eb6884bc7e443247f242b6d8a3e;p=users%2Fhch%2Fmisc.git

bpf: use rcu_read_lock_dont_migrate() for bpf_cgrp_storage_free()

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

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20250821090609.42508-3-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---

diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c
index 148da8f7ff36..0687a760974a 100644
--- a/kernel/bpf/bpf_cgrp_storage.c
+++ b/kernel/bpf/bpf_cgrp_storage.c
@@ -45,8 +45,7 @@ void bpf_cgrp_storage_free(struct cgroup *cgroup)
 {
 	struct bpf_local_storage *local_storage;
 
-	migrate_disable();
-	rcu_read_lock();
+	rcu_read_lock_dont_migrate();
 	local_storage = rcu_dereference(cgroup->bpf_cgrp_storage);
 	if (!local_storage)
 		goto out;
@@ -55,8 +54,7 @@ void bpf_cgrp_storage_free(struct cgroup *cgroup)
 	bpf_local_storage_destroy(local_storage);
 	bpf_cgrp_storage_unlock();
 out:
-	rcu_read_unlock();
-	migrate_enable();
+	rcu_read_unlock_migrate();
 }
 
 static struct bpf_local_storage_data *