Linux-Hwmon Archive on lore.kernel.org
 help / color / Atom feed
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Jonathan Corbet <corbet@lwn.net>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Guenter Roeck <linux@roeck-us.net>,
	Jean Delvare <jdelvare@suse.com>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-hwmon@vger.kernel.org,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [PATCH v2 5/6] devres: provide devm_krealloc()
Date: Thu, 2 Jul 2020 14:42:58 +0200
Message-ID: <20200702124258.GA1882489@kroah.com> (raw)
In-Reply-To: <20200629065008.27620-6-brgl@bgdev.pl>

On Mon, Jun 29, 2020 at 08:50:07AM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.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@baylibre.com>
> ---
>  .../driver-api/driver-model/devres.rst        |  1 +
>  drivers/base/devres.c                         | 50 +++++++++++++++++++
>  include/linux/device.h                        |  2 +
>  3 files changed, 53 insertions(+)
> 
> diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
> index e0b58c392e4f..0a2572c3813c 100644
> --- a/Documentation/driver-api/driver-model/devres.rst
> +++ b/Documentation/driver-api/driver-model/devres.rst
> @@ -352,6 +352,7 @@ MEM
>    devm_kfree()
>    devm_kmalloc()
>    devm_kmalloc_array()
> +  devm_krealloc()
>    devm_kmemdup()
>    devm_kstrdup()
>    devm_kvasprintf()
> diff --git a/drivers/base/devres.c b/drivers/base/devres.c
> index ed615d3b9cf1..4b8870ef6a3f 100644
> --- a/drivers/base/devres.c
> +++ b/drivers/base/devres.c
> @@ -837,6 +837,56 @@ void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp)
>  }
>  EXPORT_SYMBOL_GPL(devm_kmalloc);
>  
> +void *devm_krealloc(struct device *dev, void *ptr, size_t new_size, gfp_t gfp)
> +{
> +	struct devres *old_dr, *new_dr;
> +	struct list_head old_head;
> +	unsigned long flags;
> +	void *ret = NULL;
> +	size_t tot_size;
> +
> +	if (unlikely(!new_size)) {
> +		devm_kfree(dev, ptr);
> +		return ZERO_SIZE_PTR;
> +	}
> +
> +	if (unlikely(ZERO_OR_NULL_PTR(ptr)))
> +		return devm_kmalloc(dev, new_size, gfp);
> +
> +	if (WARN_ON(is_kernel_rodata((unsigned long)ptr)))
> +		/*
> +		 * We cannot reliably realloc a const string returned by
> +		 * devm_kstrdup_const().
> +		 */
> +		return NULL;
> +
> +	if (!check_dr_size(new_size, &tot_size))
> +		return NULL;
> +
> +	spin_lock_irqsave(&dev->devres_lock, flags);
> +
> +	old_dr = find_dr(dev, devm_kmalloc_release, devm_kmalloc_match, ptr);
> +	if (WARN_ON(!old_dr))
> +		/* Memory chunk not managed or managed by a different device. */
> +		goto out;
> +
> +	old_head = old_dr->node.entry;
> +
> +	new_dr = krealloc(old_dr, tot_size, gfp);
> +	if (!new_dr)
> +		goto out;
> +
> +	if (new_dr != old_dr)
> +		list_replace(&old_head, &new_dr->node.entry);
> +
> +	ret = new_dr->data;
> +
> +out:
> +	spin_unlock_irqrestore(&dev->devres_lock, flags);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devm_krealloc);

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?

Who wants this?

thanks,

greg k-h

  reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-29  6:50 [PATCH v2 0/6] devres: provide and use devm_krealloc() Bartosz Golaszewski
2020-06-29  6:50 ` [PATCH v2 1/6] devres: remove stray space from devm_kmalloc() definition Bartosz Golaszewski
2020-06-29  6:50 ` [PATCH v2 2/6] devres: move the size check from alloc_dr() into a separate function Bartosz Golaszewski
2020-06-29  6:50 ` [PATCH v2 3/6] device: remove 'extern' attribute from function prototypes in device.h Bartosz Golaszewski
2020-06-29  6:50 ` [PATCH v2 4/6] devres: handle zero size in devm_kmalloc() Bartosz Golaszewski
2020-07-10 13:46   ` Jon Hunter
2020-07-10 16:03     ` Bartosz Golaszewski
2020-07-10 16:11       ` Jon Hunter
2020-07-10 16:24         ` Bartosz Golaszewski
2020-07-10 16:30           ` Jon Hunter
2020-06-29  6:50 ` [PATCH v2 5/6] devres: provide devm_krealloc() Bartosz Golaszewski
2020-07-02 12:42   ` Greg Kroah-Hartman [this message]
2020-07-02 13:11     ` Bartosz Golaszewski
2020-07-06 16:38       ` Bartosz Golaszewski
2020-07-06 16:41         ` Greg Kroah-Hartman
2020-07-10 13:32         ` Greg Kroah-Hartman
2020-06-29  6:50 ` [PATCH v2 6/6] hwmon: pmbus: use more devres helpers Bartosz Golaszewski
2020-06-29 16:32   ` Guenter Roeck
2020-07-02 12:44   ` Greg Kroah-Hartman
2020-07-02 13:06     ` Bartosz Golaszewski
2020-07-02 14:29     ` Guenter Roeck
2020-07-02 12:44 ` [PATCH v2 0/6] devres: provide and use devm_krealloc() Greg Kroah-Hartman

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200702124258.GA1882489@kroah.com \
    --to=gregkh@linuxfoundation.org \
    --cc=bgolaszewski@baylibre.com \
    --cc=brgl@bgdev.pl \
    --cc=corbet@lwn.net \
    --cc=jdelvare@suse.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-hwmon@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@roeck-us.net \
    --cc=rafael@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Hwmon Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-hwmon/0 linux-hwmon/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-hwmon linux-hwmon/ https://lore.kernel.org/linux-hwmon \
		linux-hwmon@vger.kernel.org
	public-inbox-index linux-hwmon

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-hwmon


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git