[PATCH] gpu/drm/bridge/sii9234: Use common error handling code in sii9234_writebm()

[PATCH] gpu/drm/bridge/sii9234: Use common error handling code in sii9234_writebm()

[SF Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 22 Oct 2017 21:21:44 +0200

* Add a jump target so that a bit of exception handling can be better
  reused at the end of this function.

  This issue was detected by using the Coccinelle software.

* Adjust condition checks.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 drivers/gpu/drm/bridge/sii9234.c | 28 ++++++++++------------------
 1 file changed, 10 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/bridge/sii9234.c b/drivers/gpu/drm/bridge/sii9234.c
index c77000626c22..fbdacdaf485c 100644
--- a/drivers/gpu/drm/bridge/sii9234.c
+++ b/drivers/gpu/drm/bridge/sii9234.c
@@ -231,30 +231,22 @@ static int sii9234_writebm(struct sii9234 *ctx, int id, int offset,
 		return ctx->i2c_error;
 
 	ret = i2c_smbus_write_byte(client, offset);
-	if (ret < 0) {
-		dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
-			sii9234_client_name[id], offset, value);
-		ctx->i2c_error = ret;
-		return ret;
-	}
+	if (ret)
+		goto report_failure;
 
 	ret = i2c_smbus_read_byte(client);
-	if (ret < 0) {
-		dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
-			sii9234_client_name[id], offset, value);
-		ctx->i2c_error = ret;
-		return ret;
-	}
+	if (ret)
+		goto report_failure;
 
 	value = (value & mask) | (ret & ~mask);
-
 	ret = i2c_smbus_write_byte_data(client, offset, value);
-	if (ret < 0) {
-		dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
-			sii9234_client_name[id], offset, value);
-		ctx->i2c_error = ret;
-	}
+	if (!ret)
+		return 0;
 
+report_failure:
+	dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
+		sii9234_client_name[id], offset, value);
+	ctx->i2c_error = ret;
 	return ret;
 }
 
-- 
2.14.2

[PATCH v2] gpu/drm/bridge/sii9234: Use common error handling code in sii9234_writebm()

[SF Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 22 Oct 2017 21:50:51 +0200

* Add a jump target so that a bit of exception handling can be better
  reused at the end of this function.

  This issue was detected by using the Coccinelle software.

* Adjust condition checks.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---

v2:
The check for a negative error code was preserved after a call
of the function "i2c_smbus_read_byte".

 drivers/gpu/drm/bridge/sii9234.c | 28 ++++++++++------------------
 1 file changed, 10 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/bridge/sii9234.c b/drivers/gpu/drm/bridge/sii9234.c
index c77000626c22..4d8b2cc29378 100644
--- a/drivers/gpu/drm/bridge/sii9234.c
+++ b/drivers/gpu/drm/bridge/sii9234.c
@@ -231,30 +231,22 @@ static int sii9234_writebm(struct sii9234 *ctx, int id, int offset,
 		return ctx->i2c_error;
 
 	ret = i2c_smbus_write_byte(client, offset);
-	if (ret < 0) {
-		dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
-			sii9234_client_name[id], offset, value);
-		ctx->i2c_error = ret;
-		return ret;
-	}
+	if (ret)
+		goto report_failure;
 
 	ret = i2c_smbus_read_byte(client);
-	if (ret < 0) {
-		dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
-			sii9234_client_name[id], offset, value);
-		ctx->i2c_error = ret;
-		return ret;
-	}
+	if (ret < 0)
+		goto report_failure;
 
 	value = (value & mask) | (ret & ~mask);
-
 	ret = i2c_smbus_write_byte_data(client, offset, value);
-	if (ret < 0) {
-		dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
-			sii9234_client_name[id], offset, value);
-		ctx->i2c_error = ret;
-	}
+	if (!ret)
+		return 0;
 
+report_failure:
+	dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
+		sii9234_client_name[id], offset, value);
+	ctx->i2c_error = ret;
 	return ret;
 }
 
-- 
2.14.2

Re: [PATCH] gpu/drm/bridge/sii9234: Use common error handling code in sii9234_writebm()

[Dan Carpenter]

On Sun, Oct 22, 2017 at 09:32:46PM +0200, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sun, 22 Oct 2017 21:21:44 +0200
> 
> * Add a jump target so that a bit of exception handling can be better
>   reused at the end of this function.
> 
>   This issue was detected by using the Coccinelle software.
> 
> * Adjust condition checks.
> 
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>  drivers/gpu/drm/bridge/sii9234.c | 28 ++++++++++------------------
>  1 file changed, 10 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/sii9234.c b/drivers/gpu/drm/bridge/sii9234.c
> index c77000626c22..fbdacdaf485c 100644
> --- a/drivers/gpu/drm/bridge/sii9234.c
> +++ b/drivers/gpu/drm/bridge/sii9234.c
> @@ -231,30 +231,22 @@ static int sii9234_writebm(struct sii9234 *ctx, int id, int offset,
>  		return ctx->i2c_error;
>  
>  	ret = i2c_smbus_write_byte(client, offset);
> -	if (ret < 0) {
> -		dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
> -			sii9234_client_name[id], offset, value);
> -		ctx->i2c_error = ret;
> -		return ret;
> -	}
> +	if (ret)
> +		goto report_failure;
>  
>  	ret = i2c_smbus_read_byte(client);
> -	if (ret < 0) {
> -		dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
> -			sii9234_client_name[id], offset, value);
> -		ctx->i2c_error = ret;
> -		return ret;
> -	}
> +	if (ret)
> +		goto report_failure;
>  
>  	value = (value & mask) | (ret & ~mask);
> -
>  	ret = i2c_smbus_write_byte_data(client, offset, value);
> -	if (ret < 0) {
> -		dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
> -			sii9234_client_name[id], offset, value);
> -		ctx->i2c_error = ret;
> -	}
> +	if (!ret)
> +		return 0;

Ugh.  No.  Don't do success handling on the last if statement.  Also
while I personally prefer testing for non-zero, the ALSA people got
annoyed at you for changing tests for < 0 but you're doing it again.
And it introduces a bug, although I see now that you fixed it in v2.

I can't get excited about these sort of risky low value patches.

>  
> +report_failure:
> +	dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
> +		sii9234_client_name[id], offset, value);
> +	ctx->i2c_error = ret;
>  	return ret;
>  }

regards,
dan carpenter

Re: [PATCH] gpu/drm/bridge/sii9234: Use common error handling code in sii9234_writebm()

[SF Markus Elfring]

>>  	ret = i2c_smbus_write_byte_data(client, offset, value);
>> -	if (ret < 0) {
>> -		dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
>> -			sii9234_client_name[id], offset, value);
>> -		ctx->i2c_error = ret;
>> -	}
>> +	if (!ret)
>> +		return 0;
> 
> Ugh.  No.  Don't do success handling on the last if statement.

I find my approach useful in this case.


> Also while I personally prefer testing for non-zero,

I got used to this checking style to some degree.


> the ALSA people got annoyed at you for changing tests for < 0

It seems that involved software developers have got special preferences there.


> but you're doing it again.

I dared to propose such an adjustment once more.
Would you like discuss corresponding reasons any further?


> And it introduces a bug,

Unfortunately, a hiccup in my software development attention …


> although I see now that you fixed it in v2.

Thanks that you noticed also this small update.

https://patchwork.kernel.org/patch/10021767/
https://lkml.kernel.org/r/<2ecf0bb7-7129-40e4-cefc-0bc2d0f7ee8b@users.sourceforge.net>


> I can't get excited about these sort of risky low value patches.

I try again to point special software improvement opportunities out.


>> +report_failure:
>> +	dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
>> +		sii9234_client_name[id], offset, value);
>> +	ctx->i2c_error = ret;
>>  	return ret;
>>  }

How do you think about to move this source code to the end of
this function implementation?

Regards,
Markus