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Subject: Re: [PATCH V4 1/3] mtd: add new fields to nand_flash_dev{}
From: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
To: Huang Shijie <shijie8@gmail.com>
Date: Wed, 13 Mar 2013 15:13:15 +0200
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On Wed, 2013-03-13 at 21:04 +0800, Huang Shijie wrote:
> On Wed, Mar 13, 2013 at 6:54 PM, Artem Bityutskiy
> <artem.bityutskiy@linux.intel.com> wrote:
> > On Thu, 2013-03-07 at 18:49 +0800, Huang Shijie wrote:
> >> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
> >> index 591eeeb..f0a9d93 100644
> >> --- a/include/linux/mtd/nand.h
> >> +++ b/include/linux/mtd/nand.h
> >> @@ -578,6 +578,8 @@ struct nand_chip {
> >>   * @erasesize: eraseblock size in bytes (determined from the extended ID if 0)
> >>   * @chipsize: total chip size in MiB
> >>   * @options: stores various chip bit options
> >> + * @id_len: The valid length of the @id.
> >> + * @oobsize: OOB size
> >>   */
> >>  struct nand_flash_dev {
> >>       char *name;
> >> @@ -592,6 +594,8 @@ struct nand_flash_dev {
> >>       unsigned long chipsize;
> >>       unsigned long erasesize;
> >>       unsigned long options;
> >> +     unsigned long id_len;
> >> +     unsigned long oobsize;
> >>  };
> >
> > Why are these of type 'long', which is 64 bits in 64-bit architectures,
> > which seems to be unnecessarily big. Wouldn't 'unsigned int' be enough?
> >
> Frankly speaking, "uint16_t" is enough.
> "unsigned int" is too long for both the fields.

Adding a single uint16_t is useless because GCC will pad it to 32 bits
anyway. I send a patch which turns all the longs to ints. Just add
another int. And yes, do not add id_len unless you need it. Thanks!

-- 
Best Regards,
Artem Bityutskiy