linux-kernel - Re: [PATCH 02/12] nvmem: mtk-efuse: use stack for nvmem

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Date:   Fri, 20 Oct 2017 22:59:45 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 02/12] nvmem: mtk-efuse: use stack for nvmem_config
 instead of malloc'ing it

2017-10-20 22:54 GMT+09:00 Greg KH <gregkh@...uxfoundation.org>:
> On Fri, Oct 20, 2017 at 10:47:28PM +0900, Masahiro Yamada wrote:
>> 2017-10-20 22:34 GMT+09:00 Greg KH <gregkh@...uxfoundation.org>:
>> > On Mon, Oct 09, 2017 at 03:26:31PM +0200, srinivas.kandagatla@...aro.org wrote:
>> >> From: Masahiro Yamada <yamada.masahiro@...ionext.com>
>> >>
>> >> nvmem_register() copies all the members of nvmem_config to
>> >> nvmem_device.  So, nvmem_config is one-time use data during
>> >> probing.  There is no point to keep it until the driver detach.
>> >> Using stack should be no problem because nvmem_config is pretty
>> >> small.
>> >
>> > Same objection as previous patch, what is wrong with it as-is?
>> >
>>
>> It is wasting memory.
>
> The memory is freed again, after the call, right?
>

I assume your "as-is" meant devm_kzalloc().

The memory is freed when the driver is detached.

It is generally quite long time
that this struct occupies the memory for no good reason.



-- 
Best Regards
Masahiro Yamada