netdev - Re: [PATCH bpf-next v5 0/2] net: xdp: XSKMAP improvements

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Date:   Sat, 17 Aug 2019 23:28:05 +0200
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Björn Töpel <bjorn.topel@...il.com>,
        ast@...nel.org, netdev@...r.kernel.org
Cc:     magnus.karlsson@...el.com, jonathan.lemon@...il.com,
        bjorn.topel@...el.com, bruce.richardson@...el.com,
        songliubraving@...com, bpf@...r.kernel.org
Subject: Re: [PATCH bpf-next v5 0/2] net: xdp: XSKMAP improvements

On 8/15/19 11:30 AM, Björn Töpel wrote:
> This series (v5 and counting) add two improvements for the XSKMAP,
> used by AF_XDP sockets.
> 
> 1. Automatic cleanup when an AF_XDP socket goes out of scope/is
>     released. Instead of require that the user manually clears the
>     "released" state socket from the map, this is done
>     automatically. Each socket tracks which maps it resides in, and
>     remove itself from those maps at relase. A notable implementation
>     change, is that the sockets references the map, instead of the map
>     referencing the sockets. Which implies that when the XSKMAP is
>     freed, it is by definition cleared of sockets.
> 
> 2. The XSKMAP did not honor the BPF_EXIST/BPF_NOEXIST flag on insert,
>     which this patch addresses.
> 
> 
> Thanks,
> Björn
> 
> v1->v2: Fixed deadlock and broken cleanup. (Daniel)
> v2->v3: Rebased onto bpf-next
> v3->v4: {READ, WRITE}_ONCE consistency. (Daniel)
>          Socket release/map update race. (Daniel)
> v4->v5: Avoid use-after-free on XSKMAP self-assignment [1]. (Daniel)
>          Removed redundant assignment in xsk_map_update_elem().
>          Variable name consistency; Use map_entry everywhere.
> 
> [1] https://lore.kernel.org/bpf/20190802081154.30962-1-bjorn.topel@gmail.com/T/#mc68439e97bc07fa301dad9fc4850ed5aa392f385
> 
> Björn Töpel (2):
>    xsk: remove AF_XDP socket from map when the socket is released
>    xsk: support BPF_EXIST and BPF_NOEXIST flags in XSKMAP
> 
>   include/net/xdp_sock.h |  18 ++++++
>   kernel/bpf/xskmap.c    | 133 ++++++++++++++++++++++++++++++++++-------
>   net/xdp/xsk.c          |  50 ++++++++++++++++
>   3 files changed, 179 insertions(+), 22 deletions(-)
> 

Looks better, applied thanks!