linux-kernel - Re: [PATCH] Fix pointer cast for 32 bits arch

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Date:	Mon, 13 Apr 2015 12:21:53 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Peter Senna Tschudin <peter.senna@...il.com>
Cc:	driverdevel <devel@...verdev.osuosl.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jun Tian <jun.j.tian@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Garret Kelly <garret.kelly@...il.com>,
	Octavian Purdila <octavian.purdila@...el.com>,
	Nick Kralevich <nnk@...gle.com>, Alan <alan@...ux.intel.com>
Subject: Re: [PATCH] Fix pointer cast for 32 bits arch

On Mon, Apr 13, 2015 at 11:16:49AM +0200, Peter Senna Tschudin wrote:
> On Mon, Apr 13, 2015 at 11:10 AM, Dan Carpenter
> <dan.carpenter@...cle.com> wrote:
> > On Sun, Apr 12, 2015 at 11:26:43AM +0200, Peter Senna Tschudin wrote:
> >> Sparse compalins about casting void * to u64 on i386.
> >> Change the cast to resource_size_t.
> >>
> >> Signed-off-by: Peter Senna Tschudin <peter.senna@...il.com>
> >> ---
> >>
> >> Tested by compilation only. Tested for x86 and x86_64.
> >>
> >>  drivers/staging/goldfish/goldfish_nand.c | 3 ++-
> >>  include/linux/goldfish.h                 | 2 +-
> >>  2 files changed, 3 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/staging/goldfish/goldfish_nand.c b/drivers/staging/goldfish/goldfish_nand.c
> >> index d68f216..738fdc4 100644
> >> --- a/drivers/staging/goldfish/goldfish_nand.c
> >> +++ b/drivers/staging/goldfish/goldfish_nand.c
> >> @@ -87,7 +87,8 @@ static u32 goldfish_nand_cmd(struct mtd_info *mtd, enum nand_cmd cmd,
> >>               writel((u32)(addr >> 32), base + NAND_ADDR_HIGH);
> >>               writel((u32)addr, base + NAND_ADDR_LOW);
> >>               writel(len, base + NAND_TRANSFER_SIZE);
> >> -             gf_write64((u64)ptr, base + NAND_DATA, base + NAND_DATA_HIGH);
> >> +             gf_write64((resource_size_t)ptr, base + NAND_DATA,
> >> +                        base + NAND_DATA_HIGH);
> >
> > write64 is a misleading name because it only writes 32 bits on 32 bit
> > systems.
> >
> > Are you sure it's a resource_size_t?  If that's really true then this
> > code needs a lot more work.  The ifdef in gf_write64() should be
> > CONFIG_PHYS_ADDR_T_64BIT and ops->datbuf needs to updated.  It would be
> > a lot of changes...
> >
> > I *think* but I'm not positive that gf_write64 should just take a void
> > pointer like this:
> >
> > diff --git a/drivers/staging/goldfish/goldfish_nand.c b/drivers/staging/goldfish/goldfish_nand.c
> > index 213877a..92d6479 100644
> > --- a/drivers/staging/goldfish/goldfish_nand.c
> > +++ b/drivers/staging/goldfish/goldfish_nand.c
> > @@ -87,7 +87,7 @@ static u32 goldfish_nand_cmd(struct mtd_info *mtd, enum nand_cmd cmd,
> >                 writel((u32)(addr >> 32), base + NAND_ADDR_HIGH);
> >                 writel((u32)addr, base + NAND_ADDR_LOW);
> >                 writel(len, base + NAND_TRANSFER_SIZE);
> > -               gf_write64((u64)ptr, base + NAND_DATA, base + NAND_DATA_HIGH);
> > +               gf_write64(ptr, base + NAND_DATA, base + NAND_DATA_HIGH);
> >                 writel(cmd, base + NAND_COMMAND);
> >                 rv = readl(base + NAND_RESULT);
> >         }
> > diff --git a/include/linux/goldfish.h b/include/linux/goldfish.h
> > index 569236e..4cdb913 100644
> > --- a/include/linux/goldfish.h
> > +++ b/include/linux/goldfish.h
> > @@ -3,12 +3,12 @@
> >
> >  /* Helpers for Goldfish virtual platform */
> >
> > -static inline void gf_write64(unsigned long data,
> > +static inline void gf_write64(void *data,
> >                 void __iomem *portl, void __iomem *porth)
> >  {
> > -       writel((u32)data, portl);
> > +       writel((u32)(unsigned long)data, portl);
> >  #ifdef CONFIG_64BIT
> > -       writel(data>>32, porth);
> > +       writel((unsigned long)data >> 32, porth);
> >  #endif
> >  }
> >
> 
> I like this solution. Should I send a single patch changing
> gf_write64() and removing all casts when calling the gf_write64(), or
> if to split, how to split the patch?

Single patch, please.  Maybe rename the function to gf_write_ptr() or
something similar.

regards,
dan carpenter

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