Commit b0a81b94 authored Feb 24, 2020 by Thomas Gleixner Committed by Alexei Starovoitov Feb 24, 2020

bpf/trace: Remove redundant preempt_disable from trace_call_bpf()



Similar to __bpf_trace_run this is redundant because __bpf_trace_run() is
invoked from a trace point via __DO_TRACE() which already disables
preemption _before_ invoking any of the functions which are attached to a
trace point.

Remove it and add a cant_sleep() check.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145643.059995527@linutronix.de

parent 70ed0706

kernel/trace/bpf_trace.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -83,7 +83,7 @@ unsigned int trace_call_bpf(struct trace_event_call call, void ctx)
		if (in_nmi()) /* not supported yet */
		return 1;

		preempt_disable();
		cant_sleep();

		if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
		/*
		@@ -115,7 +115,6 @@ unsigned int trace_call_bpf(struct trace_event_call call, void ctx)

		out:
		__this_cpu_dec(bpf_prog_active);
		preempt_enable();

		return ret;
		}

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