On 2016-07-06 18:16, Toke Høiland-Jørgensen wrote:
> This switches ath9k over to using the mac80211 intermediate software
> queueing mechanism for data packets. It removes the queueing inside the
> driver, except for the retry queue, and instead pulls from mac80211 when
> a packet is needed. The retry queue is used to store a packet that was
> pulled but can't be sent immediately.
>
> The old code path in ath_tx_start that would queue packets has been
> removed completely, as has the qlen limit tunables (since there's no
> longer a queue in the driver to limit).
>
> Based on Tim's original patch set, but reworked quite thoroughly.
>
> Cc: Tim Shepard <s...@alum.mit.edu>
> Cc: Felix Fietkau <n...@nbd.name>
> Signed-off-by: Toke Høiland-Jørgensen <t...@toke.dk>
> ---
> Changes since v1:
> - Remove the old intermediate queueing logic completely instead of
> just disabling it.
> - Remove the qlen debug tunables.
> - Remove the force_channel parameter from struct txctl (since we just
> removed the code path that was using it).
>
> drivers/net/wireless/ath/ath9k/ath9k.h | 12 +-
> drivers/net/wireless/ath/ath9k/channel.c | 2 -
> drivers/net/wireless/ath/ath9k/debug.c | 14 +-
> drivers/net/wireless/ath/ath9k/debug.h | 2 -
> drivers/net/wireless/ath/ath9k/debug_sta.c | 4 +-
> drivers/net/wireless/ath/ath9k/init.c | 2 +-
> drivers/net/wireless/ath/ath9k/main.c | 1 +
> drivers/net/wireless/ath/ath9k/xmit.c | 307
> +++++++++++------------------
> 8 files changed, 130 insertions(+), 214 deletions(-)
Nice work!
> diff --git a/drivers/net/wireless/ath/ath9k/xmit.c
> b/drivers/net/wireless/ath/ath9k/xmit.c
> index fe795fc..4077eeb 100644
> --- a/drivers/net/wireless/ath/ath9k/xmit.c
> +++ b/drivers/net/wireless/ath/ath9k/xmit.c
> @@ -912,8 +923,16 @@ ath_tx_get_tid_subframe(struct ath_softc *sc, struct
> ath_txq *txq,
> seqno = bf->bf_state.seqno;
>
> /* do not step over block-ack window */
> - if (!BAW_WITHIN(tid->seq_start, tid->baw_size, seqno))
> + if (!BAW_WITHIN(tid->seq_start, tid->baw_size, seqno)) {
> + __skb_queue_tail(&tid->retry_q, skb);
> +
> + /* If there are other skbs in the retry q, they are
> + * probably within the BAW, so loop immediately to get
> + * one of them. Otherwise the queue can get stuck. */
> + if (!skb_queue_is_first(&tid->retry_q, skb))
> + continue;
Not sure if this can happen, but if we ever somehow end up with two skbs
in the retry queue that do not fit into the Block-Ack window, there's
potential for an infinite loop here.
- Felix
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