diff mbox

backlight: adp88x0: fix uninitialized variable use

Message ID 3850346.cL1ocQLBvP@wuerfel (mailing list archive)
State New, archived
Headers show

Commit Message

Arnd Bergmann Nov. 23, 2015, 1:44 p.m. UTC 
gcc correctly warns about both the adp8860 and adp8870 backlight
drivers using an uninitialized variable in their error handling
path:

drivers/video/backlight/adp8870_bl.c: In function 'adp8870_bl_ambient_light_zone_store':
drivers/video/backlight/adp8870_bl.c:811:11: warning: 'reg_val' may be used uninitialized in this function

This changes the code to only write back the data if it was
correctly read to start with.

As a side-note, the drivers are mostly identical, so I think they
should really be merged into one file to avoid having to fix every
bug twice.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Comments

Hennerich, Michael Nov. 23, 2015, 1:53 p.m. UTC | #1 
On 11/23/2015 02:44 PM, Arnd Bergmann wrote:
> gcc correctly warns about both the adp8860 and adp8870 backlight
> drivers using an uninitialized variable in their error handling
> path:
>
> drivers/video/backlight/adp8870_bl.c: In function 'adp8870_bl_ambient_light_zone_store':
> drivers/video/backlight/adp8870_bl.c:811:11: warning: 'reg_val' may be used uninitialized in this function
>
> This changes the code to only write back the data if it was
> correctly read to start with.
>
> As a side-note, the drivers are mostly identical, so I think they
> should really be merged into one file to avoid having to fix every
> bug twice.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Acked-by: Michael Hennerich <michael.hennerich@analog.com>

>
> diff --git a/drivers/video/backlight/adp8860_bl.c b/drivers/video/backlight/adp8860_bl.c
> index 98ffe71e8af2..f0d4c0324580 100644
> --- a/drivers/video/backlight/adp8860_bl.c
> +++ b/drivers/video/backlight/adp8860_bl.c
> @@ -621,10 +621,12 @@ static ssize_t adp8860_bl_ambient_light_zone_store(struct device *dev,
>
>   		/* Set user supplied ambient light zone */
>   		mutex_lock(&data->lock);
> -		adp8860_read(data->client, ADP8860_CFGR, &reg_val);
> -		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> -		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> -		adp8860_write(data->client, ADP8860_CFGR, reg_val);
> +		ret = adp8860_read(data->client, ADP8860_CFGR, &reg_val);
> +		if (!ret) {
> +			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> +			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> +			adp8860_write(data->client, ADP8860_CFGR, reg_val);
> +		}
>   		mutex_unlock(&data->lock);
>   	}
>
> diff --git a/drivers/video/backlight/adp8870_bl.c b/drivers/video/backlight/adp8870_bl.c
> index 9d738352d7d4..21acac90fd77 100644
> --- a/drivers/video/backlight/adp8870_bl.c
> +++ b/drivers/video/backlight/adp8870_bl.c
> @@ -807,10 +807,12 @@ static ssize_t adp8870_bl_ambient_light_zone_store(struct device *dev,
>
>   		/* Set user supplied ambient light zone */
>   		mutex_lock(&data->lock);
> -		adp8870_read(data->client, ADP8870_CFGR, &reg_val);
> -		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> -		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> -		adp8870_write(data->client, ADP8870_CFGR, reg_val);
> +		ret = adp8870_read(data->client, ADP8870_CFGR, &reg_val);
> +		if (!ret) {
> +			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> +			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> +			adp8870_write(data->client, ADP8870_CFGR, reg_val);
> +		}
>   		mutex_unlock(&data->lock);
>   	}
>
>
Lee Jones Nov. 23, 2015, 2:39 p.m. UTC | #2 
On Mon, 23 Nov 2015, Arnd Bergmann wrote:

> gcc correctly warns about both the adp8860 and adp8870 backlight
> drivers using an uninitialized variable in their error handling
> path:
> 
> drivers/video/backlight/adp8870_bl.c: In function 'adp8870_bl_ambient_light_zone_store':
> drivers/video/backlight/adp8870_bl.c:811:11: warning: 'reg_val' may be used uninitialized in this function
> 
> This changes the code to only write back the data if it was
> correctly read to start with.
> 
> As a side-note, the drivers are mostly identical, so I think they
> should really be merged into one file to avoid having to fix every
> bug twice.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Applied, thanks.

> diff --git a/drivers/video/backlight/adp8860_bl.c b/drivers/video/backlight/adp8860_bl.c
> index 98ffe71e8af2..f0d4c0324580 100644
> --- a/drivers/video/backlight/adp8860_bl.c
> +++ b/drivers/video/backlight/adp8860_bl.c
> @@ -621,10 +621,12 @@ static ssize_t adp8860_bl_ambient_light_zone_store(struct device *dev,
>  
>  		/* Set user supplied ambient light zone */
>  		mutex_lock(&data->lock);
> -		adp8860_read(data->client, ADP8860_CFGR, &reg_val);
> -		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> -		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> -		adp8860_write(data->client, ADP8860_CFGR, reg_val);
> +		ret = adp8860_read(data->client, ADP8860_CFGR, &reg_val);
> +		if (!ret) {
> +			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> +			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> +			adp8860_write(data->client, ADP8860_CFGR, reg_val);
> +		}
>  		mutex_unlock(&data->lock);
>  	}
>  
> diff --git a/drivers/video/backlight/adp8870_bl.c b/drivers/video/backlight/adp8870_bl.c
> index 9d738352d7d4..21acac90fd77 100644
> --- a/drivers/video/backlight/adp8870_bl.c
> +++ b/drivers/video/backlight/adp8870_bl.c
> @@ -807,10 +807,12 @@ static ssize_t adp8870_bl_ambient_light_zone_store(struct device *dev,
>  
>  		/* Set user supplied ambient light zone */
>  		mutex_lock(&data->lock);
> -		adp8870_read(data->client, ADP8870_CFGR, &reg_val);
> -		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> -		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> -		adp8870_write(data->client, ADP8870_CFGR, reg_val);
> +		ret = adp8870_read(data->client, ADP8870_CFGR, &reg_val);
> +		if (!ret) {
> +			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> +			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> +			adp8870_write(data->client, ADP8870_CFGR, reg_val);
> +		}
>  		mutex_unlock(&data->lock);
>  	}
>  
>
Lee Jones Nov. 23, 2015, 4:22 p.m. UTC | #3 
On Mon, 23 Nov 2015, Arnd Bergmann wrote:

> gcc correctly warns about both the adp8860 and adp8870 backlight
> drivers using an uninitialized variable in their error handling
> path:
> 
> drivers/video/backlight/adp8870_bl.c: In function 'adp8870_bl_ambient_light_zone_store':
> drivers/video/backlight/adp8870_bl.c:811:11: warning: 'reg_val' may be used uninitialized in this function
> 
> This changes the code to only write back the data if it was
> correctly read to start with.
> 
> As a side-note, the drivers are mostly identical, so I think they
> should really be merged into one file to avoid having to fix every
> bug twice.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Applied with the $SUBJECT line fixed.

> diff --git a/drivers/video/backlight/adp8860_bl.c b/drivers/video/backlight/adp8860_bl.c
> index 98ffe71e8af2..f0d4c0324580 100644
> --- a/drivers/video/backlight/adp8860_bl.c
> +++ b/drivers/video/backlight/adp8860_bl.c
> @@ -621,10 +621,12 @@ static ssize_t adp8860_bl_ambient_light_zone_store(struct device *dev,
>  
>  		/* Set user supplied ambient light zone */
>  		mutex_lock(&data->lock);
> -		adp8860_read(data->client, ADP8860_CFGR, &reg_val);
> -		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> -		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> -		adp8860_write(data->client, ADP8860_CFGR, reg_val);
> +		ret = adp8860_read(data->client, ADP8860_CFGR, &reg_val);
> +		if (!ret) {
> +			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> +			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> +			adp8860_write(data->client, ADP8860_CFGR, reg_val);
> +		}
>  		mutex_unlock(&data->lock);
>  	}
>  
> diff --git a/drivers/video/backlight/adp8870_bl.c b/drivers/video/backlight/adp8870_bl.c
> index 9d738352d7d4..21acac90fd77 100644
> --- a/drivers/video/backlight/adp8870_bl.c
> +++ b/drivers/video/backlight/adp8870_bl.c
> @@ -807,10 +807,12 @@ static ssize_t adp8870_bl_ambient_light_zone_store(struct device *dev,
>  
>  		/* Set user supplied ambient light zone */
>  		mutex_lock(&data->lock);
> -		adp8870_read(data->client, ADP8870_CFGR, &reg_val);
> -		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> -		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> -		adp8870_write(data->client, ADP8870_CFGR, reg_val);
> +		ret = adp8870_read(data->client, ADP8870_CFGR, &reg_val);
> +		if (!ret) {
> +			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
> +			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
> +			adp8870_write(data->client, ADP8870_CFGR, reg_val);
> +		}
>  		mutex_unlock(&data->lock);
>  	}
>  
>
diff mbox

Patch

diff --git a/drivers/video/backlight/adp8860_bl.c b/drivers/video/backlight/adp8860_bl.c
index 98ffe71e8af2..f0d4c0324580 100644
--- a/drivers/video/backlight/adp8860_bl.c
+++ b/drivers/video/backlight/adp8860_bl.c
@@ -621,10 +621,12 @@  static ssize_t adp8860_bl_ambient_light_zone_store(struct device *dev,
 
 		/* Set user supplied ambient light zone */
 		mutex_lock(&data->lock);
-		adp8860_read(data->client, ADP8860_CFGR, &reg_val);
-		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
-		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
-		adp8860_write(data->client, ADP8860_CFGR, reg_val);
+		ret = adp8860_read(data->client, ADP8860_CFGR, &reg_val);
+		if (!ret) {
+			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
+			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
+			adp8860_write(data->client, ADP8860_CFGR, reg_val);
+		}
 		mutex_unlock(&data->lock);
 	}
 
diff --git a/drivers/video/backlight/adp8870_bl.c b/drivers/video/backlight/adp8870_bl.c
index 9d738352d7d4..21acac90fd77 100644
--- a/drivers/video/backlight/adp8870_bl.c
+++ b/drivers/video/backlight/adp8870_bl.c
@@ -807,10 +807,12 @@  static ssize_t adp8870_bl_ambient_light_zone_store(struct device *dev,
 
 		/* Set user supplied ambient light zone */
 		mutex_lock(&data->lock);
-		adp8870_read(data->client, ADP8870_CFGR, &reg_val);
-		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
-		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
-		adp8870_write(data->client, ADP8870_CFGR, reg_val);
+		ret = adp8870_read(data->client, ADP8870_CFGR, &reg_val);
+		if (!ret) {
+			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
+			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
+			adp8870_write(data->client, ADP8870_CFGR, reg_val);
+		}
 		mutex_unlock(&data->lock);
 	}