Received-SPF: pass (google.com: best guess record for domain of linux-wireless-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Message-ID: <2518c49c96b8b5233fabcb8bafccba6b8f3155bf.camel@sipsolutions.net>
Subject: Re: [PATCH RFC/RFT 2/4] mac80211: Add API function to set the last
 TX bitrate for a station
From:   Johannes Berg <johannes@sipsolutions.net>
To:     Toke =?ISO-8859-1?Q?H=F8iland-J=F8rgensen?= <toke@redhat.com>
Cc:     linux-wireless@vger.kernel.org,
        make-wifi-fast@lists.bufferbloat.net,
        John Crispin <john@phrozen.org>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Felix Fietkau <nbd@nbd.name>
Date:   Tue, 01 Oct 2019 10:46:30 +0200
In-Reply-To: <156889576646.191202.14461472477971784776.stgit@alrua-x1>
References: <156889576422.191202.5906619710809654631.stgit@alrua-x1>
         <156889576646.191202.14461472477971784776.stgit@alrua-x1>
Content-Type: text/plain; charset="UTF-8"
User-Agent: Evolution 3.30.5 (3.30.5-1.fc29) 
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

On Thu, 2019-09-19 at 14:22 +0200, Toke Høiland-Jørgensen wrote:

Given a ULL constant:

> +/* constants for calculating reciprocals to avoid division in fast path */
> +#define IEEE80211_RECIPROCAL_DIVISOR 0x100000000ULL

[...]

> +void ieee80211_sta_set_last_tx_bitrate(struct ieee80211_sta *pubsta,
> +				       u32 rate)
> +{
> +	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
> +
> +	sta->last_tx_bitrate = rate;
> +	sta->last_tx_bitrate_reciprocal = ((u64)IEEE80211_RECIPROCAL_DIVISOR / rate);

that cast seems unnecessary?

johannes