netdev - Re: [PATCH RFC v1 2/7] rtw88: Use rtw_iterate_vifs where the iterator reads or writes registers

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Message-ID: <CAFBinCCqVpqC+CaJqTjhCj6-4rFcttQ-cFjOPwtKFbXbnop3XA@mail.gmail.com>
Date:   Sun, 25 Jul 2021 23:31:26 +0200
From:   Martin Blumenstingl <martin.blumenstingl@...glemail.com>
To:     Pkshih <pkshih@...ltek.com>
Cc:     "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
        "tony0620emma@...il.com" <tony0620emma@...il.com>,
        "kvalo@...eaurora.org" <kvalo@...eaurora.org>,
        "johannes@...solutions.net" <johannes@...solutions.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Neo Jou <neojou@...il.com>,
        Jernej Skrabec <jernej.skrabec@...il.com>
Subject: Re: [PATCH RFC v1 2/7] rtw88: Use rtw_iterate_vifs where the iterator
 reads or writes registers

Hello Ping-Ke,

On Mon, Jul 19, 2021 at 7:47 AM Pkshih <pkshih@...ltek.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Martin Blumenstingl [mailto:martin.blumenstingl@...glemail.com]
> > Sent: Sunday, July 18, 2021 4:41 AM
> > To: linux-wireless@...r.kernel.org
> > Cc: tony0620emma@...il.com; kvalo@...eaurora.org; johannes@...solutions.net; netdev@...r.kernel.org;
> > linux-kernel@...r.kernel.org; Neo Jou; Jernej Skrabec; Martin Blumenstingl
> > Subject: [PATCH RFC v1 2/7] rtw88: Use rtw_iterate_vifs where the iterator reads or writes registers
> >
> > Upcoming SDIO support may sleep in the read/write handlers. Switch
> > all users of rtw_iterate_vifs_atomic() which are either reading or
> > writing a register to rtw_iterate_vifs().
> >
> > Signed-off-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
> > ---
> >  drivers/net/wireless/realtek/rtw88/main.c | 6 +++---
> >  drivers/net/wireless/realtek/rtw88/ps.c   | 2 +-
> >  2 files changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/wireless/realtek/rtw88/main.c b/drivers/net/wireless/realtek/rtw88/main.c
> > index c6364837e83b..207161a8f5bd 100644
> > --- a/drivers/net/wireless/realtek/rtw88/main.c
> > +++ b/drivers/net/wireless/realtek/rtw88/main.c
> > @@ -229,8 +229,8 @@ static void rtw_watch_dog_work(struct work_struct *work)
> >       rtw_phy_dynamic_mechanism(rtwdev);
> >
> >       data.rtwdev = rtwdev;
> > -     /* use atomic version to avoid taking local->iflist_mtx mutex */
> > -     rtw_iterate_vifs_atomic(rtwdev, rtw_vif_watch_dog_iter, &data);
> > +
> > +     rtw_iterate_vifs(rtwdev, rtw_vif_watch_dog_iter, &data);
>
> You revert the fix of [1].
Thanks for bringing this to my attention!

> I think we can move out rtw_chip_cfg_csi_rate() from rtw_dynamic_csi_rate(), and
> add/set a field cfg_csi_rate to itera data. Then, we do rtw_chip_cfg_csi_rate()
> outside iterate function. Therefore, we can keep the atomic version of iterate_vifs.
just to make sure that I understand this correctly:
rtw_iterate_vifs_atomic can be the iterator as it was before
inside the iterator func I use something like:
    iter_data->cfg_csi_rate = rtwvif->bfee.role == RTW_BFEE_SU ||
rtwvif->bfee.role == RTW_BFEE_MU || iter_data->cfg_csi_rate;
(the last iter_data->cfg_csi_rate may read a bit strange, but I think
it's needed because there can be multiple interfaces and if any of
them has cfg_csi_rate true then we need to remember that)
then move the rtw_chip_cfg_csi_rate outside the iterator function,
taking iter_data->cfg_csi_rate to decide whether it needs to be called


Best regards,
Martin