From: "Jonathan Lemon" <jlemon@flugsvamp.com>
To: "Maxim Mikityanskiy" <maximmi@mellanox.com>
Cc: "Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Jakub Kicinski" <jakub.kicinski@netronome.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
"Björn Töpel" <bjorn.topel@intel.com>,
"Saeed Mahameed" <saeedm@mellanox.com>,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"John Fastabend" <john.fastabend@gmail.com>,
"Martin KaFai Lau" <kafai@fb.com>,
"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>
Subject: Re: [PATCH bpf-next v2] net: Don't call XDP_SETUP_PROG when nothing is changed
Date: Wed, 14 Aug 2019 10:57:19 -0700
Message-ID: <78BC2DFF-D2F5-494E-BDDE-10F42C8F9E51@flugsvamp.com> (raw)
In-Reply-To: <20190814143352.3759-1-maximmi@mellanox.com>
On 14 Aug 2019, at 7:34, Maxim Mikityanskiy wrote:
> Don't uninstall an XDP program when none is installed, and don't install
> an XDP program that has the same ID as the one already installed.
>
> dev_change_xdp_fd doesn't perform any checks in case it uninstalls an
> XDP program. It means that the driver's ndo_bpf can be called with
> XDP_SETUP_PROG asking to set it to NULL even if it's already NULL. This
> case happens if the user runs `ip link set eth0 xdp off` when there is
> no XDP program attached.
>
> The symmetrical case is possible when the user tries to set the program
> that is already set.
>
> The drivers typically perform some heavy operations on XDP_SETUP_PROG,
> so they all have to handle these cases internally to return early if
> they happen. This patch puts this check into the kernel code, so that
> all drivers will benefit from it.
>
> Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
next prev parent reply index
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-12 16:14 [PATCH bpf-next] net: Don't uninstall an XDP program when none is installed Maxim Mikityanskiy
2019-06-12 18:39 ` Björn Töpel
2019-06-12 21:15 ` Jakub Kicinski
2019-06-13 9:04 ` Björn Töpel
2019-06-13 17:26 ` Jakub Kicinski
2019-07-10 11:16 ` Maxim Mikityanskiy
2019-07-12 15:44 ` Daniel Borkmann
2019-08-14 14:34 ` [PATCH bpf-next v2] net: Don't call XDP_SETUP_PROG when nothing is changed Maxim Mikityanskiy
2019-08-14 17:57 ` Jonathan Lemon [this message]
2019-08-14 22:01 ` Jakub Kicinski
2019-08-17 21:29 ` Daniel Borkmann
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