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bpf/trace: Remove redundant preempt_disable from trace_call_bpf()

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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
This commit is contained in:
Thomas Gleixner 2020-02-24 15:01:37 +01:00 committed by Alexei Starovoitov
parent 70ed0706a4
commit b0a81b94cc
1 changed files with 1 additions and 2 deletions
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3
kernel/trace/bpf_trace.c
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@ -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;
}