Messages in this thread |  | | Date | Tue, 19 Nov 2013 15:25:36 -0500 (EST) | Subject | Re: [PATCH net v4 3/4] r8152: support stopping/waking tx queue | From | David Miller <> |
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From: Hayes Wang <hayeswang@realtek.com> Date: Tue, 19 Nov 2013 11:25:10 +0800
> The maximum packet number which a tx aggregation buffer could contain > is the buffer size / (packet size + descriptor size). > > If the tx buffer is empty and the tx queue length is more than the > maximum value which is defined above, stop the tx queue. Wake the tx > queue after any queued packet is filled in a available tx buffer. > > Signed-off-by: Hayes Wang <hayeswang@realtek.com>
This is racy.
You have nothing which synchronizes r8152_tx_agg_fill() and rtl8152_start_xmit(), therefore:
> + if (netif_queue_stopped(tp->netdev)) > + netif_wake_queue(tp->netdev); > +
A netif_stop_queue() can occur right after the netif_queue_stopped() check, meaning you can end up with the queue being stopped forever and the TX queue stuck.
I am finding this patch series _very_ tiring, every single time I take the time to review it, I find major problems.
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