linux-kernel - Re: [Outreachy kernel] [PATCH 4/4] staging: rtl8723bs: Change the type and use of a variable

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Message-ID: <YHGGBpSLj+W8ikXz@kroah.com>
Date:   Sat, 10 Apr 2021 13:03:34 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>
Cc:     outreachy-kernel@...glegroups.com, linux-staging@...ts.linux.dev,
        linux-kernel@...r.kernel.org, julia.lawall@...ia.fr
Subject: Re: [Outreachy kernel] [PATCH 4/4] staging: rtl8723bs: Change the
 type and use of a variable

On Sat, Apr 10, 2021 at 12:58:06PM +0200, Fabio M. De Francesco wrote:
> On Saturday, April 10, 2021 12:31:27 PM CEST Greg KH wrote:
> > On Sat, Apr 10, 2021 at 11:56:48AM +0200, Fabio M. De Francesco wrote:
> > > On Saturday, April 10, 2021 11:31:16 AM CEST Greg KH wrote:
> > > > On Sat, Apr 10, 2021 at 11:22:32AM +0200, Fabio M. De Francesco 
> wrote:
> > > > > Change the type of fw_current_in_ps_mode from u8 to bool, because
> > > > > it is used everywhere as a bool and, accordingly, it should be
> > > > > declared as a bool. Shorten the controlling
> > > > > expression of an 'if' statement.
> > > > > 
> > > > > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@...il.com>
> > > > > ---
> > > > > 
> > > > >  drivers/staging/rtl8723bs/hal/hal_intf.c        | 2 +-
> > > > >  drivers/staging/rtl8723bs/include/rtw_pwrctrl.h | 2 +-
> > > > >  2 files changed, 2 insertions(+), 2 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/staging/rtl8723bs/hal/hal_intf.c
> > > > > b/drivers/staging/rtl8723bs/hal/hal_intf.c index
> > > > > 96fe172ced8d..8dc4dd8c6d4c 100644
> > > > > --- a/drivers/staging/rtl8723bs/hal/hal_intf.c
> > > > > +++ b/drivers/staging/rtl8723bs/hal/hal_intf.c
> > > > > @@ -348,7 +348,7 @@ void rtw_hal_dm_watchdog(struct adapter
> > > > > *padapter)
> > > > > 
> > > > >  void rtw_hal_dm_watchdog_in_lps(struct adapter *padapter)
> > > > >  {
> > > > > 
> > > > > -	if (adapter_to_pwrctl(padapter)->fw_current_in_ps_mode == 
> true)
> > > 
> > > {
> > > 
> > > > > +	if (adapter_to_pwrctl(padapter)->fw_current_in_ps_mode) {
> > > > > 
> > > > >  		if (padapter->HalFunc.hal_dm_watchdog_in_lps)
> > > > >  		
> > > > >  			padapter-
> > > >
> > > >HalFunc.hal_dm_watchdog_in_lps(padapter); /* this
> > > >
> > > > >  			function caller is in interrupt context
> > > 
> > > */>
> > > 
> > > > >  	}
> > > > > 
> > > > > diff --git a/drivers/staging/rtl8723bs/include/rtw_pwrctrl.h
> > > > > b/drivers/staging/rtl8723bs/include/rtw_pwrctrl.h index
> > > > > 0a48f1653be5..0767dbb84199 100644
> > > > > --- a/drivers/staging/rtl8723bs/include/rtw_pwrctrl.h
> > > > > +++ b/drivers/staging/rtl8723bs/include/rtw_pwrctrl.h
> > > > > @@ -203,7 +203,7 @@ struct pwrctrl_priv {
> > > > > 
> > > > >  	u8 LpsIdleCount;
> > > > >  	u8 power_mgnt;
> > > > >  	u8 org_power_mgnt;
> > > > > 
> > > > > -	u8 fw_current_in_ps_mode;
> > > > > +	bool fw_current_in_ps_mode;
> > > > > 
> > > > >  	unsigned long	DelayLPSLastTimeStamp;
> > > > >  	s32		pnp_current_pwr_state;
> > > > >  	u8 pnp_bstop_trx;
> > > > 
> > > > If this is only checked, how can it ever be true?  Who ever sets this
> > > > value?
> > > 
> > > You're right. It is not set, therefore the "if" control expression
> > > cannot ever be "true".
> > > 
> > > Can I delete this statement in a new patch? Or you prefer I send the
> > > whole series again with this change in patch 4/4?
> > 
> > Just delete the variable from the structure entirely and when it is
> > used.
> >
> I've read the code of the function whom that 'if' statement belongs to. 
> This function takes a pointer whose name is 'padapter' and this is has 
> global scope. I think that since fw_current_in_ps_mode is dereferenced by 
> the function adapter_to_pwrctl(padapter) it can and is indeed initialized 
> and modified in some other files of the driver.

Where does that happen, and why did the build not break when you changed
the variable name?  Is the whole variable assigned to a specific
location in memory in the device?  Where is it initialized?

> That's why I'll leave the if statement as is now. If I am wrong there's 
> time to change it later in a future patch.

Don't change obviously wrong code, we can clean it up properly :)

thanks,

greg k-h