linux-kernel - Re: [PATCH 2/6] lib/test_bitmap.c: Add for_each_set

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Message-ID: <CACG_h5oNkRbusS9Qa-KR35Q=LppQxx+ah7wHpkC1FvjLQ1wHgQ@mail.gmail.com>
Date:   Fri, 24 Apr 2020 23:56:11 +0530
From:   Syed Nayyar Waris <syednwaris@...il.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        William Breathitt Gray <vilhelm.gray@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/6] lib/test_bitmap.c: Add for_each_set_clump test cases

On Fri, Apr 24, 2020 at 6:41 PM Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
>
> On Fri, Apr 24, 2020 at 3:29 PM Syed Nayyar Waris <syednwaris@...il.com> wrote:
> >
> > The introduction of the generic for_each_set_clump macro need test
> > cases to verify the implementation. This patch adds test cases for
> > scenarios in which clump sizes are 8 bits, 24 bits, 30 bits and 6 bits.
> > The cases contain situations where clump is getting split at the word
> > boundary and also when zeroes are present in the start and middle of
> > bitmap.
>
> ...
>
> >  #define expect_eq_clump8(...)          __expect_eq(clump8, ##__VA_ARGS__)
> > +#define expect_eq_clump(...)           __expect_eq(clump, ##__VA_ARGS__)
>
> What the difference with clump8() ? Can either of them use another?
>

The difference is that generic (Non-8 version) expect_eq_clump(...)
expands to __check_eq_clump(...), which further uses clump_size
variable to check for the tests. Now this clump_size can have any
value signifying number of bits (less than or equal to BITS_PER_LONG).

While the clump8 version uses a fixed (hardcoded) value '8' for clump size.

I don't think either of them can use another.

> ...
>
> >  #define CLUMP_EXP_NUMBITS 64
>
> > +static void __init test_for_each_set_clump_8(void)  /* 8 bit clumps test using
> > +                                                 new for_each_set_clump */
> > +{
>
> > +#define CLUMP_EXP_NUMBITS 64
>
> Isn't it a redefinition? Shouldn't we undef all local definitions
> above and below?
>
> Also, can we derive it's size based on ARRAY_SIZE() and clump size?

Actually this macro is to create bitmap having a particular size. The
size doesn't need to be related to or derived from clump_size
necessarily.  I believe I should hardcode it - as it is just a test
value. I will submit this change in next version. Let me know if you
think otherwise.

>
> > +       DECLARE_BITMAP(bits, CLUMP_EXP_NUMBITS);
> > +       unsigned long start, clump, clump_size = 8;
> > +
> > +       /* set bitmap to test case */
> > +       bitmap_zero(bits, CLUMP_EXP_NUMBITS);
> > +       bitmap_set_value(bits, 0x38000201, 0, 32);
> > +       bitmap_set_value(bits, 0x05ff0f38, 32, 32);
> > +
> > +       for_each_set_clump(start, clump, bits, CLUMP_EXP_NUMBITS, clump_size)
> > +               expect_eq_clump(start, CLUMP_EXP_NUMBITS, clump_exp1, &clump, clump_size);
> > +}
> > +
> > +static void __init test_for_each_set_clump_24(void)  /* 24 bit clumps */
> > +{
> > +#define CLUMP_EXP_NUMBITS_2 256
> > +       DECLARE_BITMAP(bits, CLUMP_EXP_NUMBITS_2);
> > +       unsigned long start, clump, clump_size = 24;
> > +       unsigned long size = clump_size * 10;
> > +
> > +       /* set bitmap to test case */
> > +       bitmap_zero(bits, CLUMP_EXP_NUMBITS_2);
> > +       bitmap_set_value(bits, 0xeffedcba, 0, 32);
> > +       bitmap_set_value(bits, 0xbbbbabcd, 32, 32);
> > +       bitmap_set_value(bits, 0x000000aa, 64, 32);
> > +       bitmap_set_value(bits, 0x000000aa, 96, 32);
> > +       bitmap_set_value(bits, 0x00ff0000, 128, 32);
> > +       bitmap_set_value(bits, 0xaaaaaa00, 160, 32);
> > +       bitmap_set_value(bits, 0xff000000, 192, 32);
> > +       bitmap_set_value(bits, 0x00aa0000, 224, 32);
> > +
> > +       for_each_set_clump(start, clump, bits, size, clump_size)
> > +               expect_eq_clump(start, size, clump_exp2, &clump, clump_size);
> > +}
> > +
> > +static void __init test_for_each_set_clump_30(void)   /* 30 bit clumps */
> > +{
> > +#define CLUMP_EXP_NUMBITS_2 256
> > +       DECLARE_BITMAP(bits, CLUMP_EXP_NUMBITS_2);
> > +       unsigned long start, clump, clump_size = 30;
> > +       unsigned long size = clump_size * 8;
> > +
> > +       /* set bitmap to test case */
> > +       bitmap_zero(bits, CLUMP_EXP_NUMBITS_2);
> > +       bitmap_set_value(bits, 0x00000000, 0, 32);
> > +       bitmap_set_value(bits, 0x00000000, 32, 32);
> > +       bitmap_set_value(bits, 0x00000000, 64, 32);
> > +       bitmap_set_value(bits, 0x0f000000, 96, 32);
> > +       bitmap_set_value(bits, 0x00ff0000, 128, 32);
> > +       bitmap_set_value(bits, 0xaaaaaa00, 160, 32);
> > +       bitmap_set_value(bits, 0xff000000, 192, 32);
> > +       bitmap_set_value(bits, 0x00aa0000, 224, 32);
> > +
> > +       for_each_set_clump(start, clump, bits, size, clump_size)
> > +               expect_eq_clump(start, size, clump_exp3, &clump, clump_size);
> > +}
> > +
> > +static void __init test_for_each_set_clump_6(void)   /* 6 bit clumps */
> > +{
> > +#define CLUMP_EXP_NUMBITS_2 256
> > +       DECLARE_BITMAP(bits, CLUMP_EXP_NUMBITS_2);
> > +       unsigned long start, clump, clump_size = 6;
> > +       unsigned long size = clump_size * 3;
> > +
> > +       /* set bitmap to test case */
> > +       bitmap_zero(bits, CLUMP_EXP_NUMBITS_2);
> > +       bitmap_set_value(bits, 0x00000ac0, 0, 32);
> > +       bitmap_set_value(bits, 0x00000000, 32, 32);
> > +       bitmap_set_value(bits, 0x00000000, 64, 32);
> > +       bitmap_set_value(bits, 0x0f000000, 96, 32);
> > +       bitmap_set_value(bits, 0x00ff0000, 128, 32);
> > +       bitmap_set_value(bits, 0xaaaaaa00, 160, 32);
> > +       bitmap_set_value(bits, 0xff000000, 192, 32);
> > +       bitmap_set_value(bits, 0x00aa0000, 224, 32);
> > +
> > +       for_each_set_clump(start, clump, bits, size, clump_size)
> > +               expect_eq_clump(start, size, clump_exp4, &clump, clump_size);
> > +}
>
> Can we unify all above and provide simple two test data sets:
> expected, input, clump size and other information as function
> parameter?

Yes I can do that. I will try it out in next version (v2).

>
> --
> With Best Regards,
> Andy Shevchenko

Thank You!
Syed Nayyar Waris