Re: [PATCH v3 1/3] drivers: base: Don't match devices with NULL of_node/fwnode/etc

David Gow
2024-12-19T05:45:16Z

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On Tue, 17 Dec 2024 at 04:12, Brian Norris <briannorris@chromium.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).
>
> Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> ---

Seems sensible enough to me.

Acked-by: David Gow <davidgow@google.com>

I assume this series (including the KUnit test changes) will go in via Greg.

Cheers,
-- David

>
> Changes in v3:
> * Add Rafael's Acked-by
>
> 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);
>
> --
> 2.47.1.613.gc27f4b7a9f-goog
>

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