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From: Peter Zijlstra <peterz@infradead.org>
To: Alexei Starovoitov <ast@plumgrid.com>
Cc: Ingo Molnar <mingo@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Wang Nan <wangnan0@huawei.com>, He Kuang <hekuang@huawei.com>,
	Kaixu Xia <xiakaixu@huawei.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 net-next] bpf: fix bpf_perf_event_read() helper
Date: Mon, 26 Oct 2015 13:32:00 +0100	[thread overview]
Message-ID: <20151026123200.GT2508@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <562D0208.7090608@plumgrid.com>

On Sun, Oct 25, 2015 at 09:23:36AM -0700, Alexei Starovoitov wrote:
> bpf_perf_event_read() muxes of -EINVAL into return value, but it's non
> ambiguous to the program whether it got an error or real counter value.

How can that be, the (u64)-EINVAL value is a valid counter value..
unlikely maybe, but still quite possible.

  reply	other threads:[~2015-10-26 12:32 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-23  0:10 [PATCH v3 net-next] bpf: fix bpf_perf_event_read() helper Alexei Starovoitov
2015-10-23  2:21 ` Wangnan (F)
2015-10-23  2:30   ` Alexei Starovoitov
2015-10-23  3:47 ` Wangnan (F)
2015-10-23 12:03 ` Peter Zijlstra
2015-10-23 14:42   ` Alexei Starovoitov
2015-10-23 14:54     ` Peter Zijlstra
2015-10-25  9:21     ` Ingo Molnar
2015-10-25 16:23       ` Alexei Starovoitov
2015-10-26 12:32         ` Peter Zijlstra [this message]
2015-10-26 12:54           ` Wangnan (F)
2015-10-26 21:28             ` Alexei Starovoitov
2015-10-27  4:50 ` David Miller

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