From: Daniel Borkmann <daniel@iogearbox•net>
To: Jesper Dangaard Brouer <brouer@redhat•com>,
Daniel Borkmann <borkmann@iogearbox•net>,
Alexei Starovoitov <alexei.starovoitov@gmail•com>
Cc: John Fastabend <john.r.fastabend@intel•com>, netdev@vger•kernel.org
Subject: Re: [RFC net-next PATCH 1/5] samples/bpf: xdp_tx_iptunnel make use of map_data[]
Date: Fri, 19 May 2017 17:45:25 +0200 [thread overview]
Message-ID: <591F1315.3010304@iogearbox.net> (raw)
In-Reply-To: <149512209298.14733.14668513619424960672.stgit@firesoul>
On 05/18/2017 05:41 PM, Jesper Dangaard Brouer wrote:
> There is no reason to use a compile time constant MAX_IPTNL_ENTRIES
> shared between the _user.c and _kern.c, when map_data[].def.max_entries
> can tell us dynamically what the max_entries were of the ELF map that
> the bpf loaded created.
>
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat•com>
Previous code was perhaps a bit more robust in the sense that the
order of the map wouldn't matter due to MAX_IPTNL_ENTRIES being
shared. Now you rely on it being in slot 1 (map_data[1].def.max_entries)
from "maps" section in ELF.
> samples/bpf/xdp_tx_iptunnel_common.h | 2 --
> samples/bpf/xdp_tx_iptunnel_kern.c | 2 +-
> samples/bpf/xdp_tx_iptunnel_user.c | 14 +++++++++-----
> 3 files changed, 10 insertions(+), 8 deletions(-)
Not sure it's worth it given this actually adds more code and makes
it more fragile at the same time. Only point I could see is to demo
usage of map_data[1].def.max_entries for sample code.
Perhaps at the very minimum add a warning comment to xdp_tx_iptunnel_kern.c
that should the code be further extended with additional maps, that
ordering of struct bpf_map_def entries really matters here to not break
the _user.c part.
Other than that, this should be sent as stand-alone "cleanup" ...
next prev parent reply other threads:[~2017-05-19 15:45 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-18 15:41 [RFC net-next PATCH 0/5] XDP driver feature API and handling change to xdp_buff Jesper Dangaard Brouer
2017-05-18 15:41 ` [RFC net-next PATCH 1/5] samples/bpf: xdp_tx_iptunnel make use of map_data[] Jesper Dangaard Brouer
2017-05-19 15:45 ` Daniel Borkmann [this message]
2017-05-18 15:41 ` [RFC net-next PATCH 2/5] mlx5: fix bug reading rss_hash_type from CQE Jesper Dangaard Brouer
2017-05-19 15:47 ` Daniel Borkmann
2017-05-19 23:38 ` David Miller
2017-05-22 18:27 ` Jesper Dangaard Brouer
2017-05-18 15:41 ` [RFC net-next PATCH 3/5] net: introduce XDP driver features interface Jesper Dangaard Brouer
2017-05-19 17:13 ` Daniel Borkmann
2017-05-19 23:37 ` David Miller
2017-05-20 7:53 ` Jesper Dangaard Brouer
2017-05-21 0:58 ` Daniel Borkmann
2017-05-22 14:49 ` Jesper Dangaard Brouer
2017-05-22 17:07 ` Daniel Borkmann
2017-05-30 9:58 ` Jesper Dangaard Brouer
2017-05-18 15:41 ` [RFC net-next PATCH 4/5] net: new XDP feature for reading HW rxhash from drivers Jesper Dangaard Brouer
2017-05-19 11:47 ` Jesper Dangaard Brouer
2017-05-20 3:07 ` Alexei Starovoitov
2017-05-20 3:21 ` Jakub Kicinski
2017-05-20 3:34 ` Alexei Starovoitov
2017-05-20 4:13 ` Jakub Kicinski
2017-05-21 15:55 ` Jesper Dangaard Brouer
2017-05-22 3:21 ` Alexei Starovoitov
2017-05-22 4:12 ` John Fastabend
2017-05-20 16:16 ` Tom Herbert
2017-05-21 16:04 ` Jesper Dangaard Brouer
2017-05-21 22:10 ` Tom Herbert
2017-05-22 6:39 ` Jesper Dangaard Brouer
2017-05-22 20:42 ` Jesper Dangaard Brouer
2017-05-22 21:32 ` Tom Herbert
2017-05-18 15:41 ` [RFC net-next PATCH 5/5] mlx5: add XDP rxhash feature for driver mlx5 Jesper Dangaard Brouer
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