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

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Message-ID: <Z-MtVj4NpcLuZxJv@google.com>
Date: Tue, 25 Mar 2025 15:25:26 -0700
From: Brian Norris <briannorris@...omium.org>
To: Sascha Hauer <s.hauer@...gutronix.de>
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 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.

>  	} 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?

> -	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.

Brian

> -	} else {
> -		adapter->hw_status = MWIFIEX_HW_STATUS_READY;
> -	}
> +	adapter->hw_status = MWIFIEX_HW_STATUS_READY;
>  
> -	return ret;
> +	if (adapter->if_ops.init_fw_port)
> +		adapter->if_ops.init_fw_port(adapter);
> +
> +	return 0;
>  }
>  
>  /*
...
> 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?

Brian

> -		/* set last_init_cmd before sending the command */
> -		priv->adapter->last_init_cmd = HostCmd_CMD_11N_CFG;
> -		ret = -EINPROGRESS;
> -	}
> -
>  	return ret;
>  }
...