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

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Date:   Fri, 20 Oct 2017 18:26:46 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
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

On Sat, Oct 21, 2017 at 01:18:14AM +0900, Masahiro Yamada wrote:
> 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.

Please resend the patches that I didn't apply, rebased against the
char-misc-testing branch of the char-misc.git tree.

thanks,

greg k-h