From: "Björn Töpel" <bjorn.topel@intel.com>
To: Maxim Mikityanskiy <maximmi@mellanox.com>,
Magnus Karlsson <magnus.karlsson@intel.com>
Cc: Jonathan Lemon <jonathan.lemon@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH bpf] xsk: Clear pool even for inactive queues
Date: Tue, 19 Jan 2021 15:08:36 +0100 [thread overview]
Message-ID: <9236949b-df13-9505-8ada-69ad26e03a89@intel.com> (raw)
In-Reply-To: <20210118160333.333439-1-maximmi@mellanox.com>
On 2021-01-18 17:03, Maxim Mikityanskiy wrote:
> The number of queues can change by other means, rather than ethtool. For
> example, attaching an mqprio qdisc with num_tc > 1 leads to creating
> multiple sets of TX queues, which may be then destroyed when mqprio is
> deleted. If an AF_XDP socket is created while mqprio is active,
> dev->_tx[queue_id].pool will be filled, but then real_num_tx_queues may
> decrease with deletion of mqprio, which will mean that the pool won't be
> NULLed, and a further increase of the number of TX queues may expose a
> dangling pointer.
>
> To avoid any potential misbehavior, this commit clears pool for RX and
> TX queues, regardless of real_num_*_queues, still taking into
> consideration num_*_queues to avoid overflows.
>
> Fixes: 1c1efc2af158 ("xsk: Create and free buffer pool independently from umem")
> Fixes: a41b4f3c58dd ("xsk: simplify xdp_clear_umem_at_qid implementation")
> Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Thanks, Maxim!
Acked-by: Björn Töpel <bjorn.topel@intel.com>
> ---
> net/xdp/xsk.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index 8037b04a9edd..4a83117507f5 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -108,9 +108,9 @@ EXPORT_SYMBOL(xsk_get_pool_from_qid);
>
> void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id)
> {
> - if (queue_id < dev->real_num_rx_queues)
> + if (queue_id < dev->num_rx_queues)
> dev->_rx[queue_id].pool = NULL;
> - if (queue_id < dev->real_num_tx_queues)
> + if (queue_id < dev->num_tx_queues)
> dev->_tx[queue_id].pool = NULL;
> }
>
>
next prev parent reply other threads:[~2021-01-19 23:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 16:03 [PATCH bpf] xsk: Clear pool even for inactive queues Maxim Mikityanskiy
2021-01-19 14:08 ` Björn Töpel [this message]
2021-01-19 22:00 ` patchwork-bot+netdevbpf
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