Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 8 Mar 2021 11:08:55 +0100
From:   Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
To:     Lorenzo Bianconi <lorenzo@kernel.org>
Cc:     nbd@nbd.name, linux-wireless@vger.kernel.org,
        ryder.lee@mediatek.com
Subject: Re: [PATCH] mt76: mt7915: simplify mt7915_mac_sta_poll routine
Message-ID: <YEX3t9lVlYhi4fYj@lore-desk>
References: <db48916a553fee715fc9c0c1f83f363a01218dff.1615139832.git.lorenzo@kernel.org>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
        protocol="application/pgp-signature"; boundary="gFeNC2H+kRt15nxS"
Content-Disposition: inline
In-Reply-To: <db48916a553fee715fc9c0c1f83f363a01218dff.1615139832.git.lorenzo@kernel.org>
Precedence: bulk


--gFeNC2H+kRt15nxS
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

> Drop unnecessary lock around sta_poll_list list in mt7915_mac_sta_poll
> routine.
>=20
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>

Hi Felix,

please let's drop this patch, as we discussed, there is a race on
list_del_init(&msta->poll_list).

Regards,
Lorenzo

> ---
>  drivers/net/wireless/mediatek/mt76/mt7915/mac.c | 14 +++-----------
>  1 file changed, 3 insertions(+), 11 deletions(-)
>=20
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/ne=
t/wireless/mediatek/mt76/mt7915/mac.c
> index b3168dd3baed..cde98b86e2bb 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
> @@ -117,23 +117,15 @@ static void mt7915_mac_sta_poll(struct mt7915_dev *=
dev)
> =20
>  	rcu_read_lock();
> =20
> -	while (true) {
> +	while (!list_empty(&sta_poll_list)) {
>  		bool clear =3D false;
>  		u32 addr;
> -		u16 idx;
> =20
> -		spin_lock_bh(&dev->sta_poll_lock);
> -		if (list_empty(&sta_poll_list)) {
> -			spin_unlock_bh(&dev->sta_poll_lock);
> -			break;
> -		}
>  		msta =3D list_first_entry(&sta_poll_list,
>  					struct mt7915_sta, poll_list);
>  		list_del_init(&msta->poll_list);
> -		spin_unlock_bh(&dev->sta_poll_lock);
> =20
> -		idx =3D msta->wcid.idx;
> -		addr =3D mt7915_mac_wtbl_lmac_addr(dev, idx) + 20 * 4;
> +		addr =3D mt7915_mac_wtbl_lmac_addr(dev, msta->wcid.idx) + 20 * 4;
> =20
>  		for (i =3D 0; i < IEEE80211_NUM_ACS; i++) {
>  			u32 tx_last =3D msta->airtime_ac[i];
> @@ -152,7 +144,7 @@ static void mt7915_mac_sta_poll(struct mt7915_dev *de=
v)
>  		}
> =20
>  		if (clear) {
> -			mt7915_mac_wtbl_update(dev, idx,
> +			mt7915_mac_wtbl_update(dev, msta->wcid.idx,
>  					       MT_WTBL_UPDATE_ADM_COUNT_CLEAR);
>  			memset(msta->airtime_ac, 0, sizeof(msta->airtime_ac));
>  		}
> --=20
> 2.29.2
>=20

--gFeNC2H+kRt15nxS
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----

iHUEABYIAB0WIQTquNwa3Txd3rGGn7Y6cBh0uS2trAUCYEX3tQAKCRA6cBh0uS2t
rPUgAP9mTwXac/abC9K5xi4U9DfnyEvyI9YQIdK7iauSKJdXMQEAyV0k9Q0xI6/9
ZBbr2D2u0i7QYAYtnnZhR75hpGvwwgI=
=SWNr
-----END PGP SIGNATURE-----

--gFeNC2H+kRt15nxS--