linux-kernel - Re: [PATCH v3 1/2] gpio: sim: fix an invalid _

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Date:   Sun, 17 Sep 2023 20:59:01 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Kent Gibson <warthog618@...il.com>,
        Alexey Dobriyan <adobriyan@...il.com>,
        Peter Zijlstra <peterz@...radead.org>,
        akpm@...ux-foundation.org, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH v3 1/2] gpio: sim: fix an invalid __free() usage

On Sun, Sep 17, 2023 at 6:46 PM Linus Torvalds
<torvalds@...ux-foundation.org> wrote:
>
> On Sun, 17 Sept 2023 at 02:12, Bartosz Golaszewski <brgl@...ev.pl> wrote:
> >
> > +               has_line_names = true;
> > +               max_offset = max(line->offset, max_offset);
>
> I really don't understand why you kept this old broken logic.
>
> I sent a much better version of this function that didn't need that
> pointless has_line_names thing or the 'max()' thing, by just making
> the code a lot simpler.
>

Right, it does what it's supposed to after all but IMO it's less
clear, I had to take a second look now to get it. I was wondering if
I'm simply too sleep deprived but no - it's because in your version
the max_offset variable actually holds the value of (max_offset + 1)
which makes the name untrue.

I don't want to bikeshed about it, let me know if my version is
GoodEnough(R) or do you prefer another respin.

Bart

> Whatever.
>
> > +       line_names_size = gpio_sim_get_line_names_size(bank);
> > +       if (line_names_size) {
> > +               line_names = kcalloc(line_names_size, sizeof(*line_names),
> > +                                    GFP_KERNEL);
> > +               if (!line_names)
> > +                       return ERR_PTR(-ENOMEM);
> > +
> > +               gpio_sim_set_line_names(bank, line_names);
> >
> > -       if (line_names)
> >                 properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
> >                                                 "gpio-line-names",
> >                                                 line_names, line_names_size);
> > +       }
>
> But I do like this reorganization.
>
>             Linus