Re: [PATCH 2/3] i2c: Add pointer dereference protection to i2c_match_id()

From: Grant Likely
Date: Mon Jun 02 2014 - 12:07:30 EST


On Mon, 2 Jun 2014 14:41:02 +0100, Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> 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 check in i2c_device_match(). This patch paves
> the way for other, similar code trimming.
>
> Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>

Seems reasonable.

Acked-by: Grant Likely <grant.likely@xxxxxxxxxx>

> ---
> drivers/i2c/i2c-core.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 2e47641..d0c7180 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -83,6 +83,9 @@ void i2c_transfer_trace_unreg(void)
> static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
> const struct i2c_client *client)
> {
> + if (!id)
> + return NULL;
> +
> while (id->name[0]) {
> if (strcmp(client->name, id->name) == 0)
> return id;
> @@ -108,9 +111,10 @@ 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;
> }
> --
> 1.8.3.2
>

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