diff mbox

[1/1] PM-wakeup: Deletion of an unnecessary check before the function call "wakeup_source_unregister"

Message ID 546C7E75.9080301@users.sourceforge.net (mailing list archive)
State Rejected, archived
Headers show

Commit Message

SF Markus Elfring Nov. 19, 2014, 11:26 a.m. UTC 
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Wed, 19 Nov 2014 12:21:24 +0100

The wakeup_source_unregister() function tests whether its argument is NULL
and then returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 drivers/base/power/wakeup.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

Dan Carpenter Nov. 19, 2014, 12:09 p.m. UTC | #1 
On Wed, Nov 19, 2014 at 12:26:45PM +0100, SF Markus Elfring wrote:
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -267,8 +267,7 @@ int device_wakeup_disable(struct device *dev)
>  		return -EINVAL;
>  
>  	ws = device_wakeup_detach(dev);
> -	if (ws)
> -		wakeup_source_unregister(ws);
> +	wakeup_source_unregister(ws);

In the original code, it's clear that the programmer thought about what
happens when the device_wakeup_detach() returns NULL but in the new code
that's not clear.

I guess the information is still there in the git archive, but why hide
the good code by covering it with confusing code?

regards,
dan carpenter

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Walter Harms Nov. 19, 2014, 12:54 p.m. UTC | #2 
Am 19.11.2014 13:09, schrieb Dan Carpenter:
> On Wed, Nov 19, 2014 at 12:26:45PM +0100, SF Markus Elfring wrote:
>> --- a/drivers/base/power/wakeup.c
>> +++ b/drivers/base/power/wakeup.c
>> @@ -267,8 +267,7 @@ int device_wakeup_disable(struct device *dev)
>>  		return -EINVAL;
>>  
>>  	ws = device_wakeup_detach(dev);
>> -	if (ws)
>> -		wakeup_source_unregister(ws);
>> +	wakeup_source_unregister(ws);
> 
> In the original code, it's clear that the programmer thought about what
> happens when the device_wakeup_detach() returns NULL but in the new code
> that's not clear.
> 
> I guess the information is still there in the git archive, but why hide
> the good code by covering it with confusing code?
> 

hi,
just to add an other point of view ...

device_wakeup_detach returns dev->power.wakeup what is never NULL in this case.
(not visible here but a few line before exactly this is checked)

so this code can be compacted to:
wakeup_source_unregister(device_wakeup_detach(dev));

--readability

let the maintainer decide this byte-saving vs readability

re,
 wh
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Dan Carpenter Nov. 19, 2014, 1:05 p.m. UTC | #3 
On Wed, Nov 19, 2014 at 01:54:49PM +0100, walter harms wrote:
> device_wakeup_detach returns dev->power.wakeup what is never NULL in this case.
> (not visible here but a few line before exactly this is checked)

Huh?  I don't see a NULL check.

I think you may be confusing "dev->power.can_wakeup" with
"dev->power.wakeup"?

regards,
dan carpenter


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Walter Harms Nov. 19, 2014, 1:39 p.m. UTC | #4 
Am 19.11.2014 14:05, schrieb Dan Carpenter:
> On Wed, Nov 19, 2014 at 01:54:49PM +0100, walter harms wrote:
>> device_wakeup_detach returns dev->power.wakeup what is never NULL in this case.
>> (not visible here but a few line before exactly this is checked)
> 
> Huh?  I don't see a NULL check.
> 
> I think you may be confusing "dev->power.can_wakeup" with
> "dev->power.wakeup"?
> 
>

mea culpa,
you are right  dev->power.can_wakeup != dev->power.wakeup

therefore device_wakeup_detach(dev) CAN return NULL

re,
 wh
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diff mbox

Patch

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index eb1bd2e..87dfc1d 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -267,8 +267,7 @@  int device_wakeup_disable(struct device *dev)
 		return -EINVAL;
 
 	ws = device_wakeup_detach(dev);
-	if (ws)
-		wakeup_source_unregister(ws);
+	wakeup_source_unregister(ws);
 
 	return 0;
 }