linux-kernel - Re: [PATCH v2 1/3] drivers: base: Don't match devices with NULL of

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Message-ID: <CAJZ5v0id5MxNniN7xndMWKU4mvegNZ2V-sGRC6cJ3jHCu0puCQ@mail.gmail.com>
Date: Fri, 13 Dec 2024 15:38:40 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Brian Norris <briannorris@...omium.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, linux-acpi@...r.kernel.org, 
	linux-kernel@...r.kernel.org, kunit-dev@...glegroups.com, 
	Maxime Ripard <mripard@...nel.org>, David Gow <davidgow@...gle.com>, Rae Moar <rmoar@...gle.com>, 
	linux-kselftest@...r.kernel.org, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Rob Herring <robh@...nel.org>
Subject: Re: [PATCH v2 1/3] drivers: base: Don't match devices with NULL of_node/fwnode/etc

On Thu, Dec 12, 2024 at 1:32 AM Brian Norris <briannorris@...omium.org> wrote:
>
> of_find_device_by_node(), bus_find_device_by_of_node(),
> bus_find_device_by_fwnode(), ..., all produce arbitrary results when
> provided with a NULL of_node, fwnode, ACPI handle, etc. This is
> counterintuitive, and the source of a few bugs, such as the one fixed by
> commit 5c8418cf4025 ("PCI/pwrctrl: Unregister platform device only if
> one actually exists").
>
> It's hard to imagine a good reason that these device_match_*() APIs
> should return 'true' for a NULL argument. Augment these to return 0
> (false).
>
> Signed-off-by: Brian Norris <briannorris@...omium.org>
> Reviewed-by: Rob Herring (Arm) <robh@...nel.org>

For the ACPI part

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

> ---
>
> Changes in v2:
>  * Add Rob's Reviewed-by
>
>  drivers/base/core.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 94865c9d8adc..2b7b13fc36d7 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -5246,13 +5246,13 @@ EXPORT_SYMBOL_GPL(device_match_name);
>
>  int device_match_of_node(struct device *dev, const void *np)
>  {
> -       return dev->of_node == np;
> +       return np && dev->of_node == np;
>  }
>  EXPORT_SYMBOL_GPL(device_match_of_node);
>
>  int device_match_fwnode(struct device *dev, const void *fwnode)
>  {
> -       return dev_fwnode(dev) == fwnode;
> +       return fwnode && dev_fwnode(dev) == fwnode;
>  }
>  EXPORT_SYMBOL_GPL(device_match_fwnode);
>
> @@ -5264,13 +5264,13 @@ EXPORT_SYMBOL_GPL(device_match_devt);
>
>  int device_match_acpi_dev(struct device *dev, const void *adev)
>  {
> -       return ACPI_COMPANION(dev) == adev;
> +       return adev && ACPI_COMPANION(dev) == adev;
>  }
>  EXPORT_SYMBOL(device_match_acpi_dev);
>
>  int device_match_acpi_handle(struct device *dev, const void *handle)
>  {
> -       return ACPI_HANDLE(dev) == handle;
> +       return handle && ACPI_HANDLE(dev) == handle;
>  }
>  EXPORT_SYMBOL(device_match_acpi_handle);
>
> --
> 2.47.0.338.g60cca15819-goog
>