linux-kernel - Re: [PATCH v2 3/7] kmod: split call to call_usermodehelper

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Date:	Sat, 9 Mar 2013 20:54:10 -0300
From:	Lucas De Marchi <lucas.demarchi@...fusion.mobi>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	lucas.de.marchi@...il.com, David Howells <dhowells@...hat.com>,
	James Morris <james.l.morris@...cle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/7] kmod: split call to call_usermodehelper_fns()

On Sat, Mar 9, 2013 at 5:23 PM, Oleg Nesterov <oleg@...hat.com> wrote:
> On 03/08, Lucas De Marchi wrote:
>>
>> Use call_usermodehelper_setup() + call_usermodehelper_exec() instead of
>> calling call_usermodehelper_fns(). In case the latter returns -ENOMEM
>> the cleanup function may had not been called - in this case we would
>> not free argv and module_name.
>>
>> Signed-off-by: Lucas De Marchi <lucas.demarchi@...fusion.mobi>
>
> Thanks!
>
> looks correct, but...
>
>> @@ -98,8 +100,17 @@ static int call_modprobe(char *module_name, int wait)
>>       argv[3] = module_name;  /* check free_modprobe_argv() */
>>       argv[4] = NULL;
>>
>> -     return call_usermodehelper_fns(modprobe_path, argv, envp,
>> -             wait | UMH_KILLABLE, NULL, free_modprobe_argv, NULL);
>> +     gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
>
> Why? it is never called with UMH_NO_WAIT,
>
>> +     info = call_usermodehelper_setup(modprobe_path, argv, envp,
>> +                                      gfp_mask, NULL, free_modprobe_argv,
>
> can't we simply use GFP_KERNEL?

True... I was preserving the previous behavior and didn't check the
callers of this function.
I'm going to send a v3.

Thanks
Lucas De Marchi
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