Message-ID: <ee62f808-51fc-3fe3-22f6-60cbd144ae07@collabora.com>
Date:   Wed, 15 Feb 2023 15:33:44 +0100
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Subject: Re: [PATCH] wifi: mac80211: make rate u32 in sta_set_rate_info_rx()
Content-Language: en-US
To:     Shayne Chen <shayne.chen@mediatek.com>,
        linux-wireless <linux-wireless@vger.kernel.org>
Cc:     Johannes Berg <johannes@sipsolutions.net>,
        Felix Fietkau <nbd@nbd.name>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Ryder Lee <ryder.lee@mediatek.com>,
        Evelyn Tsai <evelyn.tsai@mediatek.com>,
        linux-mediatek <linux-mediatek@lists.infradead.org>
References: <20230209110659.25447-1-shayne.chen@mediatek.com>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <20230209110659.25447-1-shayne.chen@mediatek.com>
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Il 09/02/23 12:06, Shayne Chen ha scritto:
> The value of last_rate in ieee80211_sta_rx_stats is degraded from u32 to
> u16 after being assigned to rate variable, which causes information loss
> in STA_STATS_FIELD_TYPE and later bitfields.
> 
> Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>

In struct ieee80211_sta_rx_stats, `last_rate` is u32, hence this local `rate`
must be u32, or information loss may happen. Agreed.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

P.S.: Sorry for sending twice, the first one got out of the wrong mailbox.

> ---
>   net/mac80211/sta_info.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
> index 27c737fe7fb8..bd532d3f925d 100644
> --- a/net/mac80211/sta_info.c
> +++ b/net/mac80211/sta_info.c
> @@ -2418,7 +2418,7 @@ static void sta_stats_decode_rate(struct ieee80211_local *local, u32 rate,
>   
>   static int sta_set_rate_info_rx(struct sta_info *sta, struct rate_info *rinfo)
>   {
> -	u16 rate = READ_ONCE(sta_get_last_rx_stats(sta)->last_rate);
> +	u32 rate = READ_ONCE(sta_get_last_rx_stats(sta)->last_rate);
>   
>   	if (rate == STA_STATS_RATE_INVALID)
>   		return -EINVAL;
>