Re: [PATCH v4 1/4] net: qrtr: Allow the host QRTR to assign a unique node id

[Simon Horman <horms@kernel.org>]

On Thu, Oct 22, 2026 at 07:43:07PM +0200, Manivannan Sadhasivam wrote:
> Currently, QRTR identifies each remote node by the value of the
> 'src_node_id' field in the received packet and uses the node id as the key
> to store the node to the internal 'qrtr_nodes' radix tree.
> 
> But this approach comes with a limitation. When more than one remote node
> share the same id, then QRTR can only add the first node to the radix tree
> and has to drop the successive nodes with the same node id as the 'key' in
> radix tree has to be unique. This prevents connecting identical Qcom PCIe
> WLAN devices to a single host at the same time.
> 
> To fix this limitation, allow the host QRTR to use the node id (nid)
> received from the endpoint driver during qrtr_endpoint_register() as the
> unique node id and use it as the 'key' for the internal radix tree. Also,
> store the received 'src_id' in a new 'qrtr_node->ep_nid' field and replace
> the 'ep_nid' with the unique 'nid' in the QRTR control packets if both
> differ i.e., an endpoint driver has passed a unique 'nid' during
> qrtr_endpoint_register(). To maintain symmetry, replace the 'nid' with the
> 'ep_nid' while sending the packet back to the remote node if both differ.
> 
> A node can also bridge other distant nodes, so the source id of an
> incoming packet is not always the id the endpoint advertises for itself.
> Keep adding such ids to the radix tree as additional keys for the same
> node, as it was done before this change. Otherwise the bridged nodes would
> lose their route and qrtr_sendmsg() would start failing with -ECONNRESET
> for them.
> 
> Currently, all QRTR endpoint drivers pass 'QRTR_EP_NID_AUTO' as the 'nid'
> during qrtr_endpoint_register(). So 'ep_nid' and 'nid' are same and the
> routing behavior is not changed.
> 
> Finally, since qrtr_node_rewrite_ctrl() dereferences the control packet for
> DEL_SERVER and DEL_CLIENT as well, extend the existing length check in
> qrtr_endpoint_post() to cover both types.
> 
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> ---
>  net/qrtr/af_qrtr.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++-------

Reviewed-by: Simon Horman <horms@kernel.org>