RE: [PATCH 2/3 v4] P4080/mtd: Only make elbc nand driver detect nand flash partitions

[Zang Roy-R61911 <r61911@freescale.com>]

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Monday, October 04, 2010 23:38 PM
> To: Zang Roy-R61911
> Cc: Anton Vorontsov; linux-mtd@lists.infradead.org;
dwmw2@infradead.org;
> dedekind1@gmail.com; akpm@linux-foundation.org; Lan Chunhe-B25806;
Wood Scott-
> B07421; Gala Kumar-B11780; linuxppc-dev@ozlabs.org
> Subject: Re: [PATCH 2/3 v4] P4080/mtd: Only make elbc nand driver
detect nand
> flash partitions
>=20
> On Sat, 2 Oct 2010 05:36:27 -0700
> "Zang Roy-R61911" <r61911@freescale.com> wrote:
>=20
> >
> >
> > > -----Original Message-----
> > > From: Anton Vorontsov [mailto:cbouatmailru@gmail.com]
> > > Sent: Monday, September 20, 2010 21:19 PM
> > > To: Zang Roy-R61911
> > > Cc: linux-mtd@lists.infradead.org; dwmw2@infradead.org;
> dedekind1@gmail.com;
> > > akpm@linux-foundation.org; Lan Chunhe-B25806; Wood Scott-B07421;
Gala
> Kumar-
> > > B11780; linuxppc-dev@ozlabs.org
> > > Subject: Re: [PATCH 2/3 v4] P4080/mtd: Only make elbc nand driver
detect
> nand
> > > flash partitions
> > >
> > > On Fri, Sep 17, 2010 at 03:01:08PM +0800, Roy Zang wrote:
> > > [...]
> > > > +static struct mutex fsl_elbc_nand_mutex;
> > > > +
> > > > +static int __devinit fsl_elbc_nand_probe(struct platform_device
*dev)
> > > >  {
> > > > -	struct fsl_lbc_regs __iomem *lbc =3D ctrl->regs;
> > > > +	struct fsl_lbc_regs __iomem *lbc;
> > > >  	struct fsl_elbc_mtd *priv;
> > > >  	struct resource res;
> > > > +	struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl =3D NULL;
> > >
> > > No need for =3D NULL.
> > Any harm? Or just personal habit or style? Can you explain about
why?
>=20
> Besides not wanting superfluous code on general principle, it could
> hide a bug if in the future the real initialization is missing on some
> code path.  It would become a runtime NULL dereference rather than a
> compiler warning.

Not exactly.
Per my understand, if the pointer will definitely be assigned in code
path,
it is not necessary to init it when define. for example,

char c;
char b;
char *a;
if (condition)
	a =3D &c;
else
	a =3D &b;
...

for other case, if the path will not ensure the pointer assignment, it
will be inited
when define to avoid warning. for example,

char c;
char *a =3D NULL;
if (condition)
	a =3D &c;
...

Thanks.
Roy