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

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Submitter Lee Jones
Date June 2, 2014, 1:41 p.m.
Message ID <1401716463-23457-3-git-send-email-lee.jones@linaro.org>
Download mbox | patch
Permalink /patch/354887/
State Superseded
Headers show

Comments

Lee Jones - June 2, 2014, 1:41 p.m.
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@linaro.org>
---
 drivers/i2c/i2c-core.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
Grant Likely - June 2, 2014, 4:07 p.m.
On Mon,  2 Jun 2014 14:41:02 +0100, Lee Jones <lee.jones@linaro.org> 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@linaro.org>

Seems reasonable.

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

> ---
>  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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Patch

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;
 }