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

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Message-ID: <3114102.qbl0ZuBMXl@localhost.localdomain>
Date:   Sat, 10 Apr 2021 15:53:38 +0200
From:   "Fabio M. De Francesco" <fmdefrancesco@...il.com>
To:     Julia Lawall <julia.lawall@...ia.fr>
Cc:     Greg KH <gregkh@...uxfoundation.org>,
        outreachy-kernel@...glegroups.com, linux-staging@...ts.linux.dev,
        linux-kernel@...r.kernel.org
Subject: Re: [Outreachy kernel] [PATCH 4/4] staging: rtl8723bs: Change the type and use of a variable

On Saturday, April 10, 2021 3:24:43 PM CEST Julia Lawall wrote:
> On Sat, 10 Apr 2021, Fabio M. De Francesco wrote:
> > On Saturday, April 10, 2021 2:12:28 PM CEST Julia Lawall wrote:
> > > On Sat, 10 Apr 2021, Fabio M. De Francesco wrote:
> > > > On Saturday, April 10, 2021 1:37:30 PM CEST Julia Lawall wrote:
> > > > > > That variable has global scope and is assigned at least in:
> > > > > What do you mean by global scope?  None of the following look
> > > > > like
> > > > > references to global variables.
> > > > > 
> > > > > julia
> > > > 
> > > > I just mean that fw_current_in_ps_mode is a field of a struct in a
> > > > .h
> > > > file included everywhere in this driver and that the functions whom
> > > > the following assignments belong to have not the "static" type
> > > > modifier.
> > > 
> > > OK, but a field in a structure is not a variable, and this is not
> > > what
> > > scope means.
> > 
> > You're right, a field in a structure is not a variable.
> > 
> > > int x;
> > > 
> > > outside of anything is a global variable (global scope).
> > > 
> > > int foo() {
> > > 
> > >   int x;
> > >   ...
> > > 
> > > }
> > > 
> > > Here x is a local variable.  Its scope is the body of the function.
> > > 
> > > int foo() {
> > > 
> > >   if (abc) {
> > >   
> > >     int x;
> > >     ...
> > >   
> > >   }
> > > 
> > > }
> > > 
> > > Here x is a local variable, but its scope is only in the if branch.
> > 
> > And you're right again: I needed a little refresh of my knowledge of C.
> > 
> > I've searched again in the code for the purpose of finding out if that
> > struct is initialized with global scope but I didn't find anything. I
> > didn't even find any dynamic allocation within functions that returns
> > pointers to that struct.
> > 
> > Therefore, according to Greg's request, I'll delete that stupid 'if'
> > statement in the patch series v2 that I'm about to submit.
> 
> I'm really not clear on why the if should be deleted.
> 
> julia
>
I'm supposed to delete it because of the review made by Greg. In a couple 
of previous messages he wrote:

"If this is only checked, how can it ever be true?  Who ever sets this 
value?"

and then:

"Just delete the variable from the structure entirely and when it is
used.".

However, like you, I'm not sure yet.

Thanks,

Fabio
> 
> > I've really appreciated your help.
> > 
> > Thanks,
> > 
> > Fabio
> > 
> > > julia
> > > 
> > > > Thanks,
> > > > 
> > > > Fabio
> > > > 
> > > > > > drivers/staging/rtl8723bs/core/rtw_pwrctrl.c:368:
> > > > > > pwrpriv->fw_current_in_ps_mode = false;
> > > > > > 
> > > > > > drivers/staging/rtl8723bs/core/rtw_pwrctrl.c:380:
> > > > > > pwrpriv->fw_current_in_ps_mode = true;
> > > > > > 
> > > > > > drivers/staging/rtl8723bs/hal/rtl8723b_hal_init.c:433:
> > > > > > adapter_to_pwrctl(padapter)->fw_current_in_ps_mode = false;
> > > > > > 
> > > > > > drivers/staging/rtl8723bs/core/rtw_pwrctrl.c:981:
> > > > > > pwrctrlpriv->fw_current_in_ps_mode = false;