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From: Daniel Borkmann <daniel@iogearbox.net>
To: Maxim Mikityanskiy <maximmi@mellanox.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
	"netdev@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: Sat, 17 Aug 2019 23:29:57 +0200
Message-ID: <a6a1ad31-9570-2b04-b105-155c879429fc@iogearbox.net> (raw)
In-Reply-To: <20190814143352.3759-1-maximmi@mellanox.com>

On 8/14/19 4:34 PM, 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>

Applied, thanks!

      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
2019-08-14 22:01       ` Jakub Kicinski
2019-08-17 21:29       ` Daniel Borkmann [this message]

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