bpf: Use migrate_disable/enabe() in trampoline code.

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>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145643.891428873@linutronix.de
This commit is contained in:
David Miller 2020-02-24 15:01:45 +01:00 committed by Alexei Starovoitov
parent 6eac7795e8
commit 02ad059654

View File

@ -367,8 +367,9 @@ void bpf_trampoline_put(struct bpf_trampoline *tr)
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_prog *prog, u64 start)
stats->nsecs += sched_clock() - start;
u64_stats_update_end(&stats->syncp);
}
preempt_enable();
migrate_enable();
rcu_read_unlock();
}