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 <20220224110828.2168231-2-benjamin.tissoires@redhat.com> <YhdtKN7qodX7VDPV@kroah.com>
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From:   Benjamin Tissoires <benjamin.tissoires@redhat.com>
Date:   Thu, 24 Feb 2022 14:52:52 +0100
Message-ID: <CAO-hwJKQA4v53ER-y6Qx6gK032O3a+HNxbpQVhn2GiP4UJqe5g@mail.gmail.com>
Subject: Re: [PATCH bpf-next v1 1/6] HID: initial BPF implementation
To:     Greg KH <greg@kroah.com>
Cc:     Jiri Kosina <jikos@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, Shuah Khan <shuah@kernel.org>,
        Dave Marchevsky <davemarchevsky@fb.com>,
        Joe Stringer <joe@cilium.io>,
        Tero Kristo <tero.kristo@linux.intel.com>,
        lkml <linux-kernel@vger.kernel.org>,
        "open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
        netdev@vger.kernel.org, bpf@vger.kernel.org,
        linux-kselftest@vger.kernel.org
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On Thu, Feb 24, 2022 at 12:41 PM Greg KH <greg@kroah.com> wrote:
>
> On Thu, Feb 24, 2022 at 12:08:23PM +0100, Benjamin Tissoires wrote:
> > index 000000000000..243ac45a253f
> > --- /dev/null
> > +++ b/include/uapi/linux/bpf_hid.h
> > @@ -0,0 +1,39 @@
> > +/* SPDX-License-Identifier: GPL-2.0-or-later WITH Linux-syscall-note */
> > +
> > +/*
> > + *  HID BPF public headers
> > + *
> > + *  Copyright (c) 2021 Benjamin Tissoires
> > + */
> > +
> > +#ifndef _UAPI__LINUX_BPF_HID_H__
> > +#define _UAPI__LINUX_BPF_HID_H__
> > +
> > +#include <linux/types.h>
> > +
> > +#define HID_BPF_MAX_BUFFER_SIZE              16384           /* 16kb */
> > +
> > +struct hid_device;
> > +
> > +enum hid_bpf_event {
> > +     HID_BPF_UNDEF = 0,
> > +     HID_BPF_DEVICE_EVENT,
> > +};
> > +
> > +/* type is HID_BPF_DEVICE_EVENT */
> > +struct hid_bpf_ctx_device_event {
> > +     __u8 data[HID_BPF_MAX_BUFFER_SIZE];
> > +     unsigned long size;
>
> That's not a valid type to cross the user/kernel boundry, shouldn't it
> be "__u64"?  But really, isn't __u32 enough here?

thanks. Even __u16 should be enough, given that the upper bound is
16384. I'll amend it in v2.

Cheers,
Benjamin

>
> thanks,
>
> greg k-h
>