Date: Wed, 5 Aug 2015 11:41:01 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Alexei Starovoitov <ast@plumgrid.com>
Cc: Kaixu Xia <xiakaixu@huawei.com>, davem@davemloft.net, acme@kernel.org,
        mingo@redhat.com, masami.hiramatsu.pt@hitachi.com, jolsa@kernel.org,
        daniel@iogearbox.net, wangnan0@huawei.com,
        linux-kernel@vger.kernel.org, pi3orama@163.com, hekuang@huawei.com,
        netdev@vger.kernel.org
Subject: Re: [PATCH v6 2/4] bpf: Add new bpf map type to store the pointer to
 struct perf_event
Message-ID: <20150805094101.GX25159@twins.programming.kicks-ass.net>
References: <1438678696-88289-1-git-send-email-xiakaixu@huawei.com>
 <1438678696-88289-3-git-send-email-xiakaixu@huawei.com>
 <55C0F9C7.6070901@plumgrid.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <55C0F9C7.6070901@plumgrid.com>
User-Agent: Mutt/1.5.21 (2012-12-30)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1101
Lines: 33

On Tue, Aug 04, 2015 at 10:43:35AM -0700, Alexei Starovoitov wrote:
> >+static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd)
> >+{
> >+	struct perf_event *event;
> >+	struct perf_event_attr *attr;
> >+
> >+	event = perf_event_get(fd);
> >+	if (IS_ERR(event))
> >+		return event;
> >+
> >+	attr = perf_event_attrs(event);
> >+	if (IS_ERR(attr))
> >+		return attr;
> >+
> >+	if (attr->type != PERF_TYPE_RAW &&
> >+	    attr->type != PERF_TYPE_HARDWARE) {
> >+		perf_event_release_kernel(event);
> >+		return ERR_PTR(-EINVAL);
> >+	}
> >+	return event;
> >+}
> 
> I'm not sure whether Peter wanted to see the above function to be
> in events/core.c or not.
> imo it's fine here, since perf_event_attr is an uapi struct.

Right, aside from the const issue this is fine, for the exact reason you
state, perf_event_attr is an exposed interface.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/