linux-kernel - Re: [PATCH wireless-next v5 10/10] wifi: mwifiex: drop asynchronous init waiting code

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <Z-PeH1ChtvvYPE7_@pengutronix.de>
Date: Wed, 26 Mar 2025 11:59:43 +0100
From: Sascha Hauer <s.hauer@...gutronix.de>
To: Brian Norris <briannorris@...omium.org>
Cc: Francesco Dolcini <francesco@...cini.it>,
	Johannes Berg <johannes.berg@...el.com>,
	linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org,
	David Lin <yu-hao.lin@....com>, kernel@...gutronix.de
Subject: Re: [PATCH wireless-next v5 10/10] wifi: mwifiex: drop asynchronous
 init waiting code

Hi Brian,

On Tue, Mar 25, 2025 at 03:25:26PM -0700, Brian Norris wrote:
> Hi Sascha,
> 
> On Mon, Mar 24, 2025 at 02:24:11PM +0100, Sascha Hauer wrote:
> > Historically all commands sent to the mwifiex driver have been
> > asynchronous. The different commands sent during driver initialization
> > have been queued at once and only the final command has been waited
> > for being ready before finally starting the driver.
> > 
> > This has been changed in 7bff9c974e1a ("mwifiex: send firmware
> > initialization commands synchronously"). With this the initialization
> > is finished once the last mwifiex_send_cmd_sync() (now
> > mwifiex_send_cmd()) has returned. This makes all the code used to
> > wait for the last initialization command to be finished unnecessary,
> > so it's removed in this patch.
> > 
> > Signed-off-by: Sascha Hauer <s.hauer@...gutronix.de>
> 
> There are a few things that confuse me in here. See below.
> 
> > ---
> >  drivers/net/wireless/marvell/mwifiex/cmdevt.c  | 16 ----------------
> >  drivers/net/wireless/marvell/mwifiex/init.c    | 18 +++++-------------
> >  drivers/net/wireless/marvell/mwifiex/main.c    | 25 +++----------------------
> >  drivers/net/wireless/marvell/mwifiex/main.h    |  6 ------
> >  drivers/net/wireless/marvell/mwifiex/sta_cmd.c |  6 ------
> >  drivers/net/wireless/marvell/mwifiex/util.c    | 18 ------------------
> >  6 files changed, 8 insertions(+), 81 deletions(-)
> > 
> ...
> > diff --git a/drivers/net/wireless/marvell/mwifiex/init.c b/drivers/net/wireless/marvell/mwifiex/init.c
> > index 8b61e45cd6678..fc58ca1a60ca8 100644
> > --- a/drivers/net/wireless/marvell/mwifiex/init.c
> > +++ b/drivers/net/wireless/marvell/mwifiex/init.c
> > @@ -487,7 +487,6 @@ int mwifiex_init_fw(struct mwifiex_adapter *adapter)
> >  	int ret;
> >  	struct mwifiex_private *priv;
> >  	u8 i, first_sta = true;
> > -	int is_cmd_pend_q_empty;
> >  
> >  	adapter->hw_status = MWIFIEX_HW_STATUS_INITIALIZING;
> >  
> > @@ -509,7 +508,6 @@ int mwifiex_init_fw(struct mwifiex_adapter *adapter)
> >  	}
> >  	if (adapter->mfg_mode) {
> >  		adapter->hw_status = MWIFIEX_HW_STATUS_READY;
> > -		ret = -EINPROGRESS;
> 
> Why are you dropping this line? To be fair, I'm not sure I understand
> all the manufacturing-mode support anyway, but I equally don't
> understand why you're dropping this.

Short version: This change is correct. I started a lengthy explanation
why I did this, but realized that it's better to split this patch
further up to make it more clear. I'll create a new series from this
patch.

> 
> >  	} else {
> >  		for (i = 0; i < adapter->priv_num; i++) {
> >  			ret = mwifiex_sta_init_cmd(adapter->priv[i],
> > @@ -521,18 +519,12 @@ int mwifiex_init_fw(struct mwifiex_adapter *adapter)
> >  		}
> >  	}
> >  
> > -	spin_lock_bh(&adapter->cmd_pending_q_lock);
> > -	is_cmd_pend_q_empty = list_empty(&adapter->cmd_pending_q);
> 
> I believe your reasoning around the synchronous command logic, but would
> it help to include any sort of fail-safe here for the future? Something
> like:
> 
> 	WARN_ON(!list_empty(&adapter->cmd_pending_q));
> 
> ? Or am I being overly cautious?

mwifiex_init_fw() might be called from some obscure firmware command
time out path, so let's add it just to be sure. Better safe than sorry.

> 
> > -	spin_unlock_bh(&adapter->cmd_pending_q_lock);
> > -	if (!is_cmd_pend_q_empty) {
> > -		/* Send the first command in queue and return */
> > -		if (mwifiex_main_process(adapter) != -1)
> > -			ret = -EINPROGRESS;
> 
> You need to update the function comments now that you're dropping this.

Will do.

> > diff --git a/drivers/net/wireless/marvell/mwifiex/sta_cmd.c b/drivers/net/wireless/marvell/mwifiex/sta_cmd.c
> > index f2e9f582ae818..199a8e52e5b16 100644
> > --- a/drivers/net/wireless/marvell/mwifiex/sta_cmd.c
> > +++ b/drivers/net/wireless/marvell/mwifiex/sta_cmd.c
> > @@ -2418,11 +2418,5 @@ int mwifiex_sta_init_cmd(struct mwifiex_private *priv, u8 first_sta, bool init)
> >  	ret = mwifiex_send_cmd(priv, HostCmd_CMD_11N_CFG,
> >  			       HostCmd_ACT_GEN_SET, 0, &tx_cfg, true);
> >  
> > -	if (init) {
> 
> The 'init' function parameter is no longer used. Can you drop it from
> the function signature?

Good point. I'll make an extra patch from this though to not further
obfuscate this patch.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |