Re: [PATCH] mtdoops: fix the oops_page_used array size

[Roman Tereshonkov <roman.tereshonkov@nokia.com>]

On Sun, Dec 04, 2011 at 03:44:57PM +0200, Artem Bityutskiy wrote:
> On Tue, 2011-11-29 at 12:49 +0200, Roman Tereshonkov wrote:
> > The array of unsigned long pointed by oops_page_used is allocated
> > by vmalloc which requires the size to be in bytes.
> > 
> > Signed-off-by: Roman Tereshonkov <roman.tereshonkov at nokia.com>
> > ---
> >  drivers/mtd/mtdoops.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
> > index 1e2fa62..0782b31 100644
> > --- a/drivers/mtd/mtdoops.c
> > +++ b/drivers/mtd/mtdoops.c
> > @@ -369,7 +369,7 @@ static void mtdoops_notify_add(struct mtd_info *mtd)
> >  
> >  	/* oops_page_used is a bit field */
> >  	cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages,
> > -			BITS_PER_LONG));
> > +			BITS_PER_LONG) * sizeof(unsigned long));
> 
> But it is already in bytes. I do not understand which problem this patch
> fixes - it looks incorrect to me.

BITS_PER_LONG is equal to 32.
If we want to allocate memory for 32 pages with one bit per page then
32 / BITS_PER_LONG  is equal to 1 byte that is 8 bits.
To fix it we need to multiply the result by sizeof(unsigned long) equal to 4.



Regards
Roman Tereshonkov
> 
> -- 
> Best Regards,
> Artem Bityutskiy
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