Question on checpatch.pl warning -- possible unnecessary 'out of memory' message.

Question on checpatch.pl warning -- possible unnecessary 'out of memory' message.

[Bas Peters]

Dear all,

I'm fixing up my first driver (drivers/isdn/gigaset) to get some
experience submitting patches. When I run checkpatch.pl on some of the
code, I get the following warning:
	
./drivers/isdn/gigaset/capi.c:337: WARNING: Possible unnecessary 'out of memory' message

The corresponding code is:

        cskb = alloc_skb(CAPI_DATA_B3_CONF_LEN, GFP_ATOMIC);
	        if (!cskb) {
		                dev_err(cs->dev, "%s: out of memory\n",
				__func__);
				                return;
			}

All instances of this warning refer to usage of alloc_skb using the
GFP_ATOMIC flag. Why does checkpatch show this warning? Is it not good
practice to _always_ check whether allocation succeeded or not?

I hope someone can explain the nature of this warning and, if right,
what it should look like.

With kind regards,

Bas Peters

Question on checpatch.pl warning -- possible unnecessary 'out of memory' message.

[Bruno Guedes Souto]

Bas Peters <baspeters93 <at> gmail.com> writes:

> 
> I hope someone can explain the nature of this warning and, if right,
> what it should look like.
> 
> With kind regards,
> 
> Bas Peters
> 


Have you googled this particular checkpath error?

You should use a preprocessor macro.

Regards

BGS

Question on checpatch.pl warning -- possible unnecessary 'out of memory' message.

[Leon Romanovsky]

Hi Bas,

> All instances of this warning refer to usage of alloc_skb using the
> GFP_ATOMIC flag. Why does checkpatch show this warning? Is it not good
> practice to _always_ check whether allocation succeeded or not?
>
> I hope someone can explain the nature of this warning and, if right,
> what it should look like.
I suggest you to take a look at the following thread
https://lkml.org/lkml/2014/6/10/382
As a short summary to that discussion:
1. You should check the NULL pointer.
2. You shouldn't print the error.


>
> With kind regards,
>
> Bas Peters
>
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
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-- 
Leon Romanovsky | Independent Linux Consultant
        www.leon.nu | leon at leon.nu