linux-kernel - Re: [PATCH 03/31] wifi: mwifiex: drop HostCmd_CMD_802_11_MAC

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Message-ID: <ZsxFt19nQs4D7Q7t@pengutronix.de>
Date: Mon, 26 Aug 2024 11:07:03 +0200
From: Sascha Hauer <s.hauer@...gutronix.de>
To: Brian Norris <briannorris@...omium.org>
Cc: Kalle Valo <kvalo@...nel.org>, linux-wireless@...r.kernel.org,
	Francesco Dolcini <francesco@...cini.it>, kernel@...gutronix.de,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 03/31] wifi: mwifiex: drop HostCmd_CMD_802_11_MAC_ADDRESS
 response handling

On Thu, Aug 22, 2024 at 11:07:35AM -0700, Brian Norris wrote:
> Hi Sascha,
> 
> On Tue, Aug 20, 2024 at 01:55:28PM +0200, Sascha Hauer wrote:
> > The command response handler copies the new MAC address over to
> > priv->curr_addr. The same is done in the code issuing the call
> > already, so drop the unnecessary HostCmd_CMD_802_11_MAC_ADDRESS
> > handling.
> 
> It took a bit to figure out what you meant here -- I guess you're
> referring to mwifiex_set_mac_address()? It could help to document what
> you mean.

Ok, I can clarify this a bit when sending this next time.

Right now what we have is:

1) mwifiex_set_mac_address() sets priv->curr_addr to the desired new MAC
   address
2) mwifiex_cmd_802_11_mac_address() (called from mwifiex_send_cmd())
   constructs the HostCmd_CMD_802_11_MAC_ADDRESS command, using the MAC
   address in priv->curr_addr
3) mwifiex_ret_802_11_mac_address(), called from the response handler,
   sets priv->curr_addr to the MAC address received with the command
   response, which of course is the same as we initially copied there
   in step 1), which makes 3) redundant and unnecessary

> 
> I'm also a bit torn; this command API ostensibly has a (unused so far,
> for this command) HostCmd_ACT_GEN_GET mode, in which case this *is*
> important.
> 
> If anything, I might consider dropping some of the handling in
> mwifiex_set_mac_address(), because it seems to presume (and then has to
> undo for failure) behavior of the underlying command.

What we could do instead of dropping 3) is:

1) pass the new MAC address in the data_buf argument to
   mwifiex_send_cmd()
2) instead of priv->curr_addr use data_buf in
   mwifiex_cmd_802_11_mac_address()

With this the response handler would still set priv->curr_addr in case
the command went through successfully. No need to undo priv->curr_addr
to the previous MAC address in case the command failed.

Sounds good to me. Is that where you aiming at?

Sascha

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