From: Menglong Dong <menglong8.dong@gmail.com>
Date: Thu, 21 Aug 2025 09:06:09 +0000 (+0800)
Subject: bpf: use rcu_read_lock_dont_migrate() for trampoline.c
X-Git-Tag: v6.18-rc1~175^2~79^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8e4f0b1ebcf2180ab594f204f01279a666dadf3b;p=thirdparty%2Fkernel%2Flinux.git

bpf: use rcu_read_lock_dont_migrate() for trampoline.c

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

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20250821090609.42508-8-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---

diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 0e364614c3a29..5949095e51c3d 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -899,8 +899,7 @@ static __always_inline u64 notrace bpf_prog_start_time(void)
 static u64 notrace __bpf_prog_enter_recur(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx)
 	__acquires(RCU)
 {
-	rcu_read_lock();
-	migrate_disable();
+	rcu_read_lock_dont_migrate();
 
 	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
 
@@ -949,8 +948,7 @@ static void notrace __bpf_prog_exit_recur(struct bpf_prog *prog, u64 start,
 
 	update_prog_stats(prog, start);
 	this_cpu_dec(*(prog->active));
-	migrate_enable();
-	rcu_read_unlock();
+	rcu_read_unlock_migrate();
 }
 
 static u64 notrace __bpf_prog_enter_lsm_cgroup(struct bpf_prog *prog,
@@ -960,8 +958,7 @@ static u64 notrace __bpf_prog_enter_lsm_cgroup(struct bpf_prog *prog,
 	/* Runtime stats are exported via actual BPF_LSM_CGROUP
 	 * programs, not the shims.
 	 */
-	rcu_read_lock();
-	migrate_disable();
+	rcu_read_lock_dont_migrate();
 
 	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
 
@@ -974,8 +971,7 @@ static void notrace __bpf_prog_exit_lsm_cgroup(struct bpf_prog *prog, u64 start,
 {
 	bpf_reset_run_ctx(run_ctx->saved_run_ctx);
 
-	migrate_enable();
-	rcu_read_unlock();
+	rcu_read_unlock_migrate();
 }
 
 u64 notrace __bpf_prog_enter_sleepable_recur(struct bpf_prog *prog,
@@ -1033,8 +1029,7 @@ static u64 notrace __bpf_prog_enter(struct bpf_prog *prog,
 				    struct bpf_tramp_run_ctx *run_ctx)
 	__acquires(RCU)
 {
-	rcu_read_lock();
-	migrate_disable();
+	rcu_read_lock_dont_migrate();
 
 	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
 
@@ -1048,8 +1043,7 @@ static void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start,
 	bpf_reset_run_ctx(run_ctx->saved_run_ctx);
 
 	update_prog_stats(prog, start);
-	migrate_enable();
-	rcu_read_unlock();
+	rcu_read_unlock_migrate();
 }
 
 void notrace __bpf_tramp_enter(struct bpf_tramp_image *tr)