bpf: Use migrate_disable/enabe() in trampoline code. (02ad0596) · Commits · 戴 / test

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

kernel/bpf/trampoline.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -367,8 +367,9 @@ out:
		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();
		}

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