linux-kernel - Re: [PATCH v2 1/9] lib: string_helpers: provide kfree

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Message-ID: <CAMpxmJWbws62wBcNuTeWr8xr+B0qd40kEtLTVXqxVoOzyUgp9w@mail.gmail.com>
Date:   Mon, 28 Sep 2020 15:04:05 +0200
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Bartosz Golaszewski <brgl@...ev.pl>,
        Linus Walleij <linus.walleij@...aro.org>,
        Jonathan Corbet <corbet@....net>,
        Kent Gibson <warthog618@...il.com>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        linux-doc <linux-doc@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/9] lib: string_helpers: provide kfree_strarray()

On Mon, Sep 28, 2020 at 2:55 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Mon, Sep 28, 2020 at 12:41:47PM +0200, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bgolaszewski@...libre.com>
> >
> > There's a common pattern of dynamically allocating an array of char
> > pointers and then also dynamically allocating each string in this
> > array. Provide a helper for freeing such a string array with one call.
>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> But see below.
>
> > Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
> > ---
> >  include/linux/string_helpers.h |  2 ++
> >  lib/string_helpers.c           | 25 +++++++++++++++++++++++++
> >  2 files changed, 27 insertions(+)
> >
> > diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
> > index 86f150c2a6b6..55b25120a1c6 100644
> > --- a/include/linux/string_helpers.h
> > +++ b/include/linux/string_helpers.h
> > @@ -94,4 +94,6 @@ char *kstrdup_quotable(const char *src, gfp_t gfp);
> >  char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp);
> >  char *kstrdup_quotable_file(struct file *file, gfp_t gfp);
> >
> > +void kfree_strarray(char **str_array, size_t num_str);
> > +
> >  #endif
> > diff --git a/lib/string_helpers.c b/lib/string_helpers.c
> > index 963050c0283e..bfa4c9f3ca0a 100644
> > --- a/lib/string_helpers.c
> > +++ b/lib/string_helpers.c
> > @@ -649,3 +649,28 @@ char *kstrdup_quotable_file(struct file *file, gfp_t gfp)
> >       return pathname;
> >  }
> >  EXPORT_SYMBOL_GPL(kstrdup_quotable_file);
> > +
> > +/**
> > + * kfree_strarray - free a number of dynamically allocated strings contained
> > + *                  in an array and the array itself
> > + *
> > + * @str_array: Dynamically allocated array of strings to free. If NULL - the
> > + *             function does nothing.
> > + * @num_str: Number of strings (starting from the beginning of the array) to
> > + *           free.
> > + *
> > + * Passing a non-null str_array and num_str == 0 as well as NULL str_array
> > + * are valid use-cases.
> > + */
> > +void kfree_strarray(char **str_array, size_t num_str)
>
> Hmm... I have missed your answer to
>  str_array -> array
>  num_str -> n
>
> The rationale behind dropping str is to avoid duplicates in the name of the
> function and its parameters. 'array' is harder to avoid, but also possible,
> though I leave it to you.
>

Are you fine with me fixing this when applying the patches?

Bart