Re: [PATCHv3 1/2] nl80211: add support for mcs masks

[Wen Gong <wgong@codeaurora.org>]

On 2012-01-29 00:25, Simon Wunderlich wrote:
> Allow to set mcs masks through nl80211. We also allow to set MCS
> rates but no legacy rates (and vice versa).
> 
> Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
> Signed-off-by: Mathias Kretschmer 
> <mathias.kretschmer@fokus.fraunhofer.de>
> ---
>  include/linux/nl80211.h |    4 +++
>  include/net/cfg80211.h  |    3 +-
>  net/wireless/nl80211.c  |   61 
> ++++++++++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 65 insertions(+), 3 deletions(-)
> 
...
> @@ -5421,12 +5451,20 @@ static int nl80211_set_tx_bitrate_mask(struct
> sk_buff *skb,
>  		sband = rdev->wiphy.bands[i];
>  		mask.control[i].legacy =
>  			sband ? (1 << sband->n_bitrates) - 1 : 0;
> +		if (sband)
> +			memcpy(mask.control[i].mcs,
> +			       sband->ht_cap.mcs.rx_mask,
> +			       sizeof(mask.control[i].mcs));
when use command: "iw wlan0 set bitrates legacy-5 6", I want to set it 
fixed in 6M rate.
this copy mcs rate will add the mcs rate here and condition "if 
(tb[NL80211_TXRATE_MCS])"
is false, then mcs rate will not clear and lead a mistake result.
> +		else
> +			memset(mask.control[i].mcs, 0,
> +			       sizeof(mask.control[i].mcs));
>  	}
> 
>  	/*
>  	 * The nested attribute uses enum nl80211_band as the index. This 
> maps
>  	 * directly to the enum ieee80211_band values used in cfg80211.
>  	 */
> +	BUILD_BUG_ON(NL80211_MAX_SUPP_HT_RATES > IEEE80211_HT_MCS_MASK_LEN * 
> 8);
>  	nla_for_each_nested(tx_rates, info->attrs[NL80211_ATTR_TX_RATES], 
> rem)
>  	{
>  		enum ieee80211_band band = nla_type(tx_rates);
> @@ -5442,7 +5480,28 @@ static int nl80211_set_tx_bitrate_mask(struct
> sk_buff *skb,
>  				sband,
>  				nla_data(tb[NL80211_TXRATE_LEGACY]),
>  				nla_len(tb[NL80211_TXRATE_LEGACY]));
> -			if (mask.control[band].legacy == 0)
> +		}
> +		if (tb[NL80211_TXRATE_MCS]) {

false for "iw wlan0 set bitrates legacy-5 6", so ht_rateset_to_mask will 
not enter and mcs rate will not clear.

> +			if (!ht_rateset_to_mask(
> +					sband,
> +					nla_data(tb[NL80211_TXRATE_MCS]),
> +					nla_len(tb[NL80211_TXRATE_MCS]),
> +					mask.control[band].mcs))
> +				return -EINVAL;
> +		}
> +
> +		if (mask.control[band].legacy == 0) {
> +			/* don't allow empty legacy rates if HT
> +			 * is not even supported. */
> +			if (!rdev->wiphy.bands[band]->ht_cap.ht_supported)
> +				return -EINVAL;
> +
> +			for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++)
> +				if (mask.control[band].mcs[i])
> +					break;
> +
> +			/* legacy and mcs rates may not be both empty */
> +			if (i == IEEE80211_HT_MCS_MASK_LEN)
>  				return -EINVAL;
>  		}
>  	}