linux-kernel - Re: [PATCH v2 5/6] devres: provide devm

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Date:   Thu, 2 Jul 2020 15:11:44 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Jonathan Corbet <corbet@....net>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Jean Delvare <jdelvare@...e.com>,
        linux-doc <linux-doc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-hwmon@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH v2 5/6] devres: provide devm_krealloc()

On Thu, Jul 2, 2020 at 2:42 PM Greg Kroah-Hartman
<gregkh@...uxfoundation.org> wrote:
>
> On Mon, Jun 29, 2020 at 08:50:07AM +0200, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bgolaszewski@...libre.com>
> >
> > Implement the managed variant of krealloc(). This function works with
> > all memory allocated by devm_kmalloc() (or devres functions using it
> > implicitly like devm_kmemdup(), devm_kstrdup() etc.).
> >
> > Managed realloc'ed chunks can be manually released with devm_kfree().
> >
> > Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>

[snip!]

>
> That's a lot of logic that does not seem to match up with the krealloc()
> logic in mm/slab_common.c, are you sure we need to do all of that?
>

What are you referring to exactly? The check for rodata? It's because
devm_kfree() handles this case, while regular kfree() (or krealloc())
doesn't - there's kfree_const() but no devm_kfree_const().

> Who wants this?

The hwmon commit I mentioned in my response to patch 6/6 explicitly
mentions the lack of this helper.

Bartosz