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Message-ID: <20241019091817.GR1697@kernel.org>
Date: Sat, 19 Oct 2024 10:18:17 +0100
From: Simon Horman <horms@...nel.org>
To: Denis Kenzior <denkenz@...il.com>
Cc: netdev@...r.kernel.org, Marcel Holtmann <marcel@...tmann.org>,
Andy Gross <agross@...nel.org>,
Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v1 03/10] net: qrtr: support identical node ids
On Fri, Oct 18, 2024 at 01:18:21PM -0500, Denis Kenzior wrote:
> Add support for tracking multiple endpoints that may have conflicting
> node identifiers. This is achieved by using both the node and endpoint
> identifiers as the key inside the radix_tree data structure.
>
> For backward compatibility with existing clients, the previous key
> schema (node identifier only) is preserved. However, this schema will
> only support the first endpoint/node combination. This is acceptable
> for legacy clients as support for multiple endpoints with conflicting
> node identifiers was not previously possible.
>
> Signed-off-by: Denis Kenzior <denkenz@...il.com>
> Reviewed-by: Marcel Holtmann <marcel@...tmann.org>
> Reviewed-by: Andy Gross <agross@...nel.org>
> ---
> net/qrtr/af_qrtr.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
> index be275871fb2a..e83d491a8da9 100644
> --- a/net/qrtr/af_qrtr.c
> +++ b/net/qrtr/af_qrtr.c
> @@ -418,12 +418,20 @@ static struct qrtr_node *qrtr_node_lookup(unsigned int nid)
> static void qrtr_node_assign(struct qrtr_node *node, unsigned int nid)
> {
> unsigned long flags;
> + unsigned long key;
>
> if (nid == QRTR_EP_NID_AUTO)
> return;
>
> spin_lock_irqsave(&qrtr_nodes_lock, flags);
> - radix_tree_insert(&qrtr_nodes, nid, node);
> +
> + /* Always insert with the endpoint_id + node_id */
> + key = (unsigned long)node->ep->id << 32 | nid;
Hi Denis,
On systems with 32-bit longs, such as ARM, this will overflow.
> + radix_tree_insert(&qrtr_nodes, key, node);
> +
> + if (!radix_tree_lookup(&qrtr_nodes, nid))
> + radix_tree_insert(&qrtr_nodes, nid, node);
> +
> if (node->nid == QRTR_EP_NID_AUTO)
> node->nid = nid;
> spin_unlock_irqrestore(&qrtr_nodes_lock, flags);
> --
> 2.45.2
>
>
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