On 14.10.2013, at 21:18, Felix Fietkau <nbd@xxxxxxxxxxx> wrote:
> The regression was introduced in the following commit:
>
> 0967e01e8e713ed2982fb4eba8ba13794e9a6e89
> "ath5k: make use of the new rate control API"
>
> ath5k_tx_frame_completed saves the intended per-rate retry counts before
> they are cleared by ieee80211_tx_info_clear_status, however at this
> point the information in info->status.rates is incomplete.
>
> This causes significant throughput degradation and excessive packet loss
> on links where high bit rates don't work properly.
>
> Move the copy from bf->rates a few lines up to ensure that the saved
> retry counts are updated, and that they are really cleared in
> info->status.rates after the call to ieee80211_tx_info_clear_status.
>
> Cc: stable@xxxxxxxxxxxxxxx # 3.10+
> Cc: Thomas Huehn <thomas@xxxxxxxxxxxxxxxxxxxxxxx>
> Cc: Benjamin Vahl <bvahl@xxxxxxxxxxxxxxxxxxxxxxx>
> Reported-by: Ben West <ben@xxxxxxxxxxxx>
> Signed-off-by: Felix Fietkau <nbd@xxxxxxxxxxx>
Good catch !
Acked-by: Thomas Huehn <thomas@xxxxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/net/wireless/ath/ath5k/base.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
> index 48161ed..69f58b0 100644
> --- a/drivers/net/wireless/ath/ath5k/base.c
> +++ b/drivers/net/wireless/ath/ath5k/base.c
> @@ -1663,15 +1663,15 @@ ath5k_tx_frame_completed(struct ath5k_hw *ah, struct sk_buff *skb,
> ah->stats.tx_bytes_count += skb->len;
> info = IEEE80211_SKB_CB(skb);
>
> + size = min_t(int, sizeof(info->status.rates), sizeof(bf->rates));
> + memcpy(info->status.rates, bf->rates, size);
> +
> tries[0] = info->status.rates[0].count;
> tries[1] = info->status.rates[1].count;
> tries[2] = info->status.rates[2].count;
>
> ieee80211_tx_info_clear_status(info);
>
> - size = min_t(int, sizeof(info->status.rates), sizeof(bf->rates));
> - memcpy(info->status.rates, bf->rates, size);
> -
> for (i = 0; i < ts->ts_final_idx; i++) {
> struct ieee80211_tx_rate *r =
> &info->status.rates[i];
> --
> 1.8.0.2
>
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