From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] [PATCH net-next] tun: fix multiqueue rx
Date: Sat, 17 Nov 2018 21:11:26 -0800 (PST)
Message-ID: <20181117.211126.1736118365709071572.davem@davemloft.net>
References: <20181116041016.39852-1-matthew.cover@stackpath.com>
        <20181116070015.1759-1-matthew.cover@stackpath.com>
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From: Matthew Cover <werekraken@gmail.com>
Date: Fri, 16 Nov 2018 00:00:15 -0700

> When writing packets to a descriptor associated with a combined queue, the
> packets should end up on that queue.
> 
> Before this change all packets written to any descriptor associated with a
> tap interface end up on rx-0, even when the descriptor is associated with a
> different queue.
> 
> The rx traffic can be generated by either of the following.
>   1. a simple tap program which spins up multiple queues and writes packets
>      to each of the file descriptors
>   2. tx from a qemu vm with a tap multiqueue netdev
> 
> The queue for rx traffic can be observed by either of the following (done
> on the hypervisor in the qemu case).
>   1. a simple netmap program which opens and reads from per-queue
>      descriptors
>   2. configuring RPS and doing per-cpu captures with rxtxcpu
> 
> Alternatively, if you printk() the return value of skb_get_rx_queue() just
> before each instance of netif_receive_skb() in tun.c, you will get 65535
> for every skb.
> 
> Calling skb_record_rx_queue() to set the rx queue to the queue_index fixes
> the association between descriptor and rx queue.
> 
> Signed-off-by: Matthew Cover <matthew.cover@stackpath.com>

If this is intended to target -stable as well, which some responses seem to
indicate, you need to respin and submit this against 'net'.

Thanks.