Subject: [RFC patch 05/19] perf/bpf: Remove preempt disable around BPF invocation

From: Thomas Gleixner <[email-masked]>
Date: Fri, 14 Feb 2020 14:39:22 +0100

The BPF invocation from the perf event overflow handler does not require to
disable preemption because this is called from NMI or at least hard
interrupt context which is already non-preemptible.

Signed-off-by: Thomas Gleixner <[email-masked]>
---
 kernel/events/core.c |    2 --
 1 file changed, 2 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9206,7 +9206,6 @@ static void bpf_overflow_handler(struct
 	int ret = 0;
 
 	ctx.regs = perf_arch_bpf_user_pt_regs(regs);
-	preempt_disable();
 	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
 		goto out;
 	rcu_read_lock();
@@ -9214,7 +9213,6 @@ static void bpf_overflow_handler(struct
 	rcu_read_unlock();
 out:
 	__this_cpu_dec(bpf_prog_active);
-	preempt_enable();
 	if (!ret)
 		return;