linux-kernel - Re: [PATCH 01/12] nvmem: imx-iim: use stack for nvmem

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Date:   Sat, 21 Oct 2017 01:18:14 +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 01/12] nvmem: imx-iim: use stack for nvmem_config instead
 of malloc'ing it

2017-10-20 23:47 GMT+09:00 Greg KH <gregkh@...uxfoundation.org>:
> On Fri, Oct 20, 2017 at 11:26:16PM +0900, Masahiro Yamada wrote:
>> 2017-10-20 22:54 GMT+09:00 Greg KH <gregkh@...uxfoundation.org>:
>> > On Fri, Oct 20, 2017 at 10:47:16PM +0900, Masahiro Yamada wrote:
>> >> Hi Greg,
>> >>
>> >> 2017-10-20 22:32 GMT+09:00 Greg KH <gregkh@...uxfoundation.org>:
>> >> > On Mon, Oct 09, 2017 at 03:26:30PM +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.
>> >> >>
>> >> >> Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
>> >> >> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
>> >> >> ---
>> >> >>  drivers/nvmem/imx-iim.c | 27 ++++++++++++---------------
>> >> >>  1 file changed, 12 insertions(+), 15 deletions(-)
>> >> >>
>> >> >> diff --git a/drivers/nvmem/imx-iim.c b/drivers/nvmem/imx-iim.c
>> >> >> index 52ff65e0673f..a5992602709a 100644
>> >> >> --- a/drivers/nvmem/imx-iim.c
>> >> >> +++ b/drivers/nvmem/imx-iim.c
>> >> >> @@ -34,7 +34,6 @@ struct imx_iim_drvdata {
>> >> >>  struct iim_priv {
>> >> >>       void __iomem *base;
>> >> >>       struct clk *clk;
>> >> >> -     struct nvmem_config nvmem;
>> >> >>  };
>> >> >>
>> >> >>  static int imx_iim_read(void *context, unsigned int offset,
>> >> >> @@ -108,7 +107,7 @@ static int imx_iim_probe(struct platform_device *pdev)
>> >> >>       struct resource *res;
>> >> >>       struct iim_priv *iim;
>> >> >>       struct nvmem_device *nvmem;
>> >> >> -     struct nvmem_config *cfg;
>> >> >> +     struct nvmem_config cfg = {};
>> >> >
>> >> > You do realize you are now not zeroing out this structure, and have to
>> >> > explicitly initialize all of the fields, right?
>> >>
>> >> Why?
>> >>
>> >> I am surely zeroing out the structure.
>> >>
>> >> Did you miss "= {};" in my code?
>> >
>> > Are you sure that does zero it out?  I know we have had issues with this
>> > in the past...
>>
>> Do you have a reference for that?
>>
>> All members that are not specified in the initializer
>> are set to 0 (or NULL).
>>
>> "git show c7836d1593b87cb813c58cf64e08b052ebbe2a78"
>> and do you agree that this is correct?
>
> Ugh, you are right, that's what I get for reviewing 250+ patches at a
> time, my fault, sorry for the noise.
>
> Can you resend these?
>
> thanks,
>
> greg k-h


For what?

Srinivas said he based the series on char-misc,
and this is the first patch of the series.

It should be applied cleanly to char-misc.
(and 05/12 too, if you obey the patch order)


If you are in trouble, please let me know
the base commit it should be rebased on.


-- 
Best Regards
Masahiro Yamada