Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <973c3afc-2ea6-ff05-2c61-d047bf69867f@nbd.name>
Date:   Thu, 1 Dec 2022 11:51:51 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0)
 Gecko/20100101 Thunderbird/102.5.0
Subject: Re: [PATCH 5/9] wifi: mt76: mt7996: add MAC support
Content-Language: en-US
To:     Kalle Valo <kvalo@kernel.org>,
        Shayne Chen <shayne.chen@mediatek.com>
Cc:     linux-wireless <linux-wireless@vger.kernel.org>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Ryder Lee <ryder.lee@mediatek.com>,
        Evelyn Tsai <evelyn.tsai@mediatek.com>,
        Bo Jiao <Bo.Jiao@mediatek.com>,
        linux-mediatek <linux-mediatek@lists.infradead.org>
References: <20221122084554.9494-1-shayne.chen@mediatek.com>
 <20221122084554.9494-6-shayne.chen@mediatek.com> <87zgc7mmr8.fsf@kernel.org>
From:   Felix Fietkau <nbd@nbd.name>
In-Reply-To: <87zgc7mmr8.fsf@kernel.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 01.12.22 11:39, Kalle Valo wrote:
> Shayne Chen <shayne.chen@mediatek.com> writes:
> 
>> (Split the big patch into smaller intermediate patches by functionality
>> for easier review. Refer to the cover letter for more info.)
>>
>> Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
> 
> [...]
> 
>> +static void mt7996_mac_sta_poll(struct mt7996_dev *dev)
>> +{
>> +	static const u8 ac_to_tid[] = {
>> +		[IEEE80211_AC_BE] = 0,
>> +		[IEEE80211_AC_BK] = 1,
>> +		[IEEE80211_AC_VI] = 4,
>> +		[IEEE80211_AC_VO] = 6
>> +	};
>> +	struct ieee80211_sta *sta;
>> +	struct mt7996_sta *msta;
>> +	struct rate_info *rate;
>> +	u32 tx_time[IEEE80211_NUM_ACS], rx_time[IEEE80211_NUM_ACS];
>> +	LIST_HEAD(sta_poll_list);
>> +	int i;
>> +
>> +	spin_lock_bh(&dev->sta_poll_lock);
>> +	list_splice_init(&dev->sta_poll_list, &sta_poll_list);
>> +	spin_unlock_bh(&dev->sta_poll_lock);
>> +
>> +	rcu_read_lock();
>> +
>> +	while (true) {
> 
> In upstream we have a preference that there's some kind of limit for
> loops, to avoid neverending loops.
This loop pulls entries from the on-stack sta_poll_list and bails out 
when the list is empty, so it's impossible for it to be neverending.

- Felix