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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        David Miller <davem@davemloft.net>, bpf@vger.kernel.org,
        netdev@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Sebastian Sewior <bigeasy@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Clark Williams <williams@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Ingo Molnar <mingo@kernel.org>
Subject: Re: [RFC patch 07/19] bpf: Provide BPF_PROG_RUN_PIN_ON_CPU() macro
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References: <20200214133917.304937432@linutronix.de> <20200214161503.595780887@linutronix.de> <20200214185027.nx6enxvmghucai2d@localhost>
Date:   Fri, 14 Feb 2020 20:36:09 +0100
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Mathieu Desnoyers <mathieu.desnoyers@efficios.com> writes:

> On 14-Feb-2020 02:39:24 PM, Thomas Gleixner wrote:
> [...]
>> +#define BPF_PROG_RUN_PIN_ON_CPU(prog, ctx) ({				\
>> +	u32 ret;							\
>> +	migrate_disable();						\
>> +	ret = __BPF_PROG_RUN(prog, ctx, bpf_dispatcher_nopfunc);	\
>> +	migrate_enable();						\
>> +	ret; })
>
> Does it really have to be a statement expression with a local variable ?
>
> If so, we should consider renaming "ret" to "__ret" to minimize the
> chances of a caller issuing BPF_PROG_RUN_PIN_ON_CPU with "ret" as
> prog or ctx argument, which would lead to unexpected results.

Indeed. That really can be an inline.

Thanks,

        tglx