Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20201026150851.528148-1-aleksandrnogikh@gmail.com>
 <20201026150851.528148-3-aleksandrnogikh@gmail.com> <CA+FuTSeR5n4xSpzMxAYX=kyy0aJYz52FVR=EjqK8_-LVqcqpXA@mail.gmail.com>
In-Reply-To: <CA+FuTSeR5n4xSpzMxAYX=kyy0aJYz52FVR=EjqK8_-LVqcqpXA@mail.gmail.com>
From:   Aleksandr Nogikh <nogikh@google.com>
Date:   Tue, 27 Oct 2020 15:31:23 +0300
Message-ID: <CANp29Y7WOFZ-YWV84BucHvFRg628He+NDsGqCZfdsn_crwVW2A@mail.gmail.com>
Subject: Re: [PATCH v3 2/3] net: add kcov handle to skb extensions
To:     Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc:     Aleksandr Nogikh <aleksandrnogikh@gmail.com>,
        David Miller <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Johannes Berg <johannes@sipsolutions.net>,
        Eric Dumazet <edumazet@google.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Marco Elver <elver@google.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        linux-wireless <linux-wireless@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Mon, Oct 26, 2020 at 7:57 PM Willem de Bruijn
<willemdebruijn.kernel@gmail.com> wrote:
[...]
> If the handle does not need to be set if zero, why then set it if the
> skb has extensions?

The point of that condition is to avoid unnecessary allocations of skb exte=
nsion
objects. At the same time, one would expect skb_get_kcov_handle to return t=
he
latest value that was set via skb_set_kcov_handle. So if a buffer already h=
as a
non-zero kcov_handle and skb_set_kcov_handle is called to set it to zero, i=
t
should be set to zero.

> skb_ext_add and skb_ext_find are not defined unless CONFIG_SKB_EXTENSIONS=
.
>
> Perhaps CONFIG_KCOV should be made to select that?

Yes, thank you for pointing it out. I=E2=80=99ll fix it in the next version=
.