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Message-ID: <20200108204307.GC14503@yury-thinkpad>
Date: Wed, 8 Jan 2020 12:43:07 -0800
From: Yury Norov <yury.norov@...il.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Rasmus Villemoes <linux@...musvillemoes.dk>,
linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>,
Guenter Roeck <linux@...ck-us.net>
Subject: Re: [PATCH v1 1/2] lib/test_bitmap: Correct test data offsets for
32-bit
On Wed, Jan 08, 2020 at 10:26:54PM +0200, Andy Shevchenko wrote:
> On Wed, Jan 08, 2020 at 11:24:37AM -0800, Yury Norov wrote:
> > On Wed, Jan 08, 2020 at 08:46:10PM +0200, Andy Shevchenko wrote:
> > > On 32-bit platform the size of long is only 32 bits which makes wrong offset
> > > in the array of 64 bit size.
> > >
> > > Calculate offset based on BITS_PER_LONG.
> > >
> > > Fixes: 30544ed5de43 ("lib/bitmap: introduce bitmap_replace() helper")
> > > Reported-by: Guenter Roeck <linux@...ck-us.net>
> > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
>
> > > unsigned int nbits = 64;
> > > + unsigned int step = DIV_ROUND_UP(nbits, BITS_PER_LONG);
> >
> > Step is already defined in this file:
> > #define step (sizeof(u64) / sizeof(unsigned long))
>
> ...and later undefined.
>
> > to avoid the same problem in other test cases. Introducing another variant of
> > it looks messy.
>
> I don't see any problem.
The problem is that you reimplement the functionality instead of
reuse.
> > > DECLARE_BITMAP(bmap, 1024);
> > >
> > > bitmap_zero(bmap, 1024);
> > > - bitmap_replace(bmap, &exp2[0], &exp2[1], exp2_to_exp3_mask, nbits);
> > > + bitmap_replace(bmap, &exp2[0 * step], &exp2[1 * step], exp2_to_exp3_mask, nbits);
> > > expect_eq_bitmap(bmap, exp3_0_1, nbits);
> >
> > If nbits is always 64, why don't you pass 64 directly?
>
> We may use any setting. For now it's 64, but nothing prevents us to extend to,
> let's say, 75.
>
> --
> With Best Regards,
> Andy Shevchenko
>
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