linux-kernel - Re: s390/net: Deletion of unnecessary checks before two function calls

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Date:	Mon, 03 Nov 2014 17:50:48 +0100
From:	SF Markus Elfring <elfring@...rs.sourceforge.net>
To:	Dan Carpenter <dan.carpenter@...cle.com>
CC:	Ursula Braun <ursula.braun@...ibm.com>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	Frank Blaschka <blaschka@...ux.vnet.ibm.com>,
	linux390@...ibm.com, linux-s390@...r.kernel.org,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
	trivial@...nel.org, Coccinelle <cocci@...teme.lip6.fr>
Subject: Re: s390/net: Deletion of unnecessary checks before two function
 calls

> After your patch then it will print warning messages.

To which messages do you refer to?


> The truth is I think that all these patches are bad and they make the
> code harder to read.
> 
> Before:  The code is clear and there is no NULL dereference.

Where do you stumble on a null pointer access?


>  After:  You have to remember that rtw_free_netdev() accepts NULL
> 	 pointers but free_netdev() does not accept NULL pointers.

Are any improvements needed for the corresponding documentation to make it
better accessible besides the source code?


> The if statements are there for *human* readers to understand and you are
> making it harder for humans to understand the code.

Is there a target conflict between source code understandability
and software efficiency?


> Even for kfree(), just removing the if statement is not really the right
> fix.  We do it because everyone knows kfree(), but what Julia Lawall
> said is the real correct way change the code and make it simpler for
> people to understand:
> 
> https://lkml.org/lkml/2014/10/31/452

You refer to another update suggestion for the software area
"staging: rtl8188eu".
Do you find adjustments for jump labels easier to accept than the simple
deletion of specific null pointer checks?


> I know it's fun to send automated patches but these make the code worse
> and they waste reviewer time.

I hope that small automated changes can also help to improve affected
source files.

Regards,
Markus
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