linux-kernel - Re: [PATCH] staging: rtl8723bs: simplify control flow

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Date:   Fri, 1 Apr 2022 18:46:19 -0400
From:   Sevinj Aghayeva <sevinj.aghayeva@...il.com>
To:     Ira Weiny <ira.weiny@...el.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org,
        outreachy@...ts.linux.dev
Subject: Re: [PATCH] staging: rtl8723bs: simplify control flow

On Fri, Apr 01, 2022 at 02:34:04PM -0700, Ira Weiny wrote:
> On Fri, Apr 01, 2022 at 07:46:35AM -0400, Sevinj Aghayeva wrote:
> > The function iterates an index from 0 to NUM_PMKID_CACHE and returns
> > the first index for which the condition is true. If no such index is
> > found, the function returns -1. Current code has a complex control
> > flow that obfuscates this simple task. Replace it with a loop.
> > 
> > Also, given the shortened function body, replace the long variable
> > name psecuritypriv with a short variable name p.
> > 
> > Reported by checkpatch:
> > 
> > WARNING: else is not generally useful after a break or return
> > 
> > Signed-off-by: Sevinj Aghayeva <sevinj.aghayeva@...il.com>
> 
> Wow!  Nice find!  This is a huge clean up.  Extra kudos recognizing that it is
> not just the else statement which is broken here!

Thanks! It took me a while to realize what this loop is doing.

> The only issue for the patch is that I don't see any maintainer emailed?
> However, I don't see a maintainer listed in the MAINTAINERS file so ...
> 
> Reviewed-by: Ira Weiny <ira.weiny@...el.com>

Thanks for the review!

Greg, please do not apply this yet. After I sent out the patch, I
noticed the comment at the top of the function:

/*  Ported from 8185: IsInPreAuthKeyList(). (Renamed from SecIsInPreAuthKeyList(), 2006-10-13.) */

So I did a git grep to find the original function and fix it as well,
and it looks like there are three copies of the same function in
different files:

$ git grep IsInPreAuthKeyList
r8188eu/core/rtw_mlme.c:/*  Ported from 8185: IsInPreAuthKeyList(). (Renamed from SecIsInPreAuthKeyList(), 2006-10-13.) */
rtl8712/rtl871x_mlme.c: * Ported from 8185: IsInPreAuthKeyList().
rtl8723bs/core/rtw_mlme.c:/*  Ported from 8185: IsInPreAuthKeyList(). (Renamed from SecIsInPreAuthKeyList(), 2006-10-13.) */

I will later send a v2 patch that replaces all of them.

Thanks

> > ---
> >  drivers/staging/rtl8723bs/core/rtw_mlme.c | 28 ++++++-----------------
> >  1 file changed, 7 insertions(+), 21 deletions(-)
> > 
> > diff --git a/drivers/staging/rtl8723bs/core/rtw_mlme.c b/drivers/staging/rtl8723bs/core/rtw_mlme.c
> > index d5bb3a5bd2fb..3eacf8f9d236 100644
> > --- a/drivers/staging/rtl8723bs/core/rtw_mlme.c
> > +++ b/drivers/staging/rtl8723bs/core/rtw_mlme.c
> > @@ -2036,28 +2036,14 @@ int rtw_restruct_wmm_ie(struct adapter *adapter, u8 *in_ie, u8 *out_ie, uint in_
> >  
> >  static int SecIsInPMKIDList(struct adapter *Adapter, u8 *bssid)
> >  {
> > -	struct security_priv *psecuritypriv = &Adapter->securitypriv;
> > -	int i = 0;
> > -
> > -	do {
> > -		if ((psecuritypriv->PMKIDList[i].bUsed) &&
> > -				(!memcmp(psecuritypriv->PMKIDList[i].Bssid, bssid, ETH_ALEN))) {
> > -			break;
> > -		} else {
> > -			i++;
> > -			/* continue; */
> > -		}
> > -
> > -	} while (i < NUM_PMKID_CACHE);
> > -
> > -	if (i == NUM_PMKID_CACHE) {
> > -		i = -1;/*  Could not find. */
> > -	} else {
> > -		/*  There is one Pre-Authentication Key for the specific BSSID. */
> > -	}
> > -
> > -	return i;
> > +	struct security_priv *p = &Adapter->securitypriv;
> > +	int i;
> >  
> > +	for (i = 0; i < NUM_PMKID_CACHE; i++)
> > +		if ((p->PMKIDList[i].bUsed) &&
> > +				(!memcmp(p->PMKIDList[i].Bssid, bssid, ETH_ALEN)))
> > +			return i;
> > +	return -1;
> >  }
> >  
> >  /*  */
> > -- 
> > 2.25.1
> >