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Subject[RFC patch 12/19] bpf: Use migrate_disable/enabe() in trampoline code.
From: David Miller <davem@davemloft.net>

Instead of preemption disable/enable to reflect the purpose. This allows
PREEMPT_RT to substitute it with an actual migration disable
implementation. On non RT kernels this is still mapped to
preempt_disable/enable().

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
kernel/bpf/trampoline.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -367,8 +367,9 @@ void bpf_trampoline_put(struct bpf_tramp
mutex_unlock(&trampoline_mutex);
}

-/* The logic is similar to BPF_PROG_RUN, but with explicit rcu and preempt that
- * are needed for trampoline. The macro is split into
+/* The logic is similar to BPF_PROG_RUN, but with an explicit
+ * rcu_read_lock() and migrate_disable() which are required
+ * for the trampoline. The macro is split into
* call _bpf_prog_enter
* call prog->bpf_func
* call __bpf_prog_exit
@@ -378,7 +379,7 @@ u64 notrace __bpf_prog_enter(void)
u64 start = 0;

rcu_read_lock();
- preempt_disable();
+ migrate_disable();
if (static_branch_unlikely(&bpf_stats_enabled_key))
start = sched_clock();
return start;
@@ -401,7 +402,7 @@ void notrace __bpf_prog_exit(struct bpf_
stats->nsecs += sched_clock() - start;
u64_stats_update_end(&stats->syncp);
}
- preempt_enable();
+ migrate_enable();
rcu_read_unlock();
}

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