linux-kernel - Re: [Cocci] [PATCH 1/1] kprobes: Deletion of an unnecessary check before the function call "module

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Date:	Sun, 16 Nov 2014 15:26:05 +0100
From:	SF Markus Elfring <elfring@...rs.sourceforge.net>
To:	Julia Lawall <julia.lawall@...6.fr>
CC:	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>,
	"David S. Miller" <davem@...emloft.net>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org,
	Coccinelle <cocci@...teme.lip6.fr>
Subject: Re: [Cocci] [PATCH 1/1] kprobes: Deletion of an unnecessary check
 before the function call "module_put"

>> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
>> index 3995f54..f1e7d45 100644
>> --- a/kernel/kprobes.c
>> +++ b/kernel/kprobes.c
>> @@ -1527,8 +1527,7 @@ int register_kprobe(struct kprobe *p)
>>  out:
>>  	mutex_unlock(&kprobe_mutex);
>>
>> -	if (probed_mod)
>> -		module_put(probed_mod);
>> +	module_put(probed_mod);
> 
> There is an out label, so please check whether the labels could not be
> better positioned to avoid calling module_put when it is not needed.

I do not see refactoring opportunities around jump labels in this use case
for the implementation of the register_kprobe() function so far because
the mutex_unlock() function must be called.
Would you like to suggest any other source code fine-tuning?

Regards,
Markus
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