Re: [PATCH] staging: vt6656: Use fls instead of for loop in vnt_update_top_rates

[Oscar Carter <oscar.carter@gmx.com>]

On Mon, Apr 20, 2020 at 03:10:59PM +0300, Dan Carpenter wrote:
> On Sun, Apr 19, 2020 at 12:09:21PM +0200, Oscar Carter wrote:
> > -	for (i = RATE_11M;; i--) {
> > -		if (priv->basic_rates & (u16)(1 << i)) {
> > -			top_cck = i;
> > -			break;
> > -		}
> > -		if (i == RATE_1M)
> > -			break;
> > -	}
> > +	pos = fls(priv->basic_rates & GENMASK(RATE_54M, RATE_6M));
> > +	priv->top_ofdm_basic_rate = pos ? pos-- : RATE_24M;
>                                           ^^^^^
> Argh...  Come on.  I don't want to have to break out the C standard to
> see if this is defined behavior and where the sequence points are.  A
> pre-op would be clear but the most clear thing is to write it like this:
>
> 	priv->top_ofdm_basic_rate = pos ? (pos - 1) : RATE_24M;
>
Ok, I do the modification as you suggested and resend a new version.
>
> >
> > -	priv->top_cck_basic_rate = top_cck;
> > +	pos = fls(priv->basic_rates & GENMASK(RATE_11M, RATE_1M));
> > +	priv->top_cck_basic_rate = pos ? pos-- : RATE_1M;
>                                          ^^^^^
> Same.
>
> regards,
> dan carpenter
>
thanks,
oscar carter