Re: [PATCH v4 1/8] i2c: Add pointer dereference protection to i2c_match_id()

Lee Jones
2015-09-11T09:32:01Z

On Wed, 09 Sep 2015, Kieran Bingham wrote:

> From: Lee Jones <lee.jones@linaro.org>
>
> Here we're providing dereference protection for i2c_match_id(), which
> saves us having to do it each time it's called. We're also stripping
> out the (now) needless checks in i2c_device_match(). This patch paves
> the way for other, similar code trimming.
>
> Acked-by: Grant Likely <grant.likely@linaro.org>
> Signed-off-by: Lee Jones <lee.jones@linaro.org>

SoB?

> ---
> drivers/i2c/i2c-core.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index c83e4d1..30d8a77 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -450,6 +450,9 @@ static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
> static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
> const struct i2c_client *client)
> {
> + if (!(id && client))
> + return NULL;
> +
> while (id->name[0]) {
> if (strcmp(client->name, id->name) == 0)
> return id;
> @@ -463,8 +466,6 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
> struct i2c_client *client = i2c_verify_client(dev);
> struct i2c_driver *driver;
>
> - if (!client)
> - return 0;
>
> /* Attempt an OF style match */
> if (of_driver_match_device(dev, drv))
> @@ -475,9 +476,10 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
> return 1;
>
> driver = to_i2c_driver(drv);
> - /* match on an id table if there is one */
> - if (driver->id_table)
> - return i2c_match_id(driver->id_table, client) != NULL;
> +
> + /* Finally an I2C match */
> + if (i2c_match_id(driver->id_table, client))
> + return 1;
>
> return 0;
> }

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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