Re: [PATCH v16 01/14] bitops: Introduce the for_each_set_clump8 macro

From: Andy Shevchenko <andriy.shevchenko@linux•intel.com>
To: William Breathitt Gray <vilhelm.gray@gmail•com>
Cc: linux-arch@vger•kernel.org, Arnd Bergmann <arnd@arndb•de>,
	linux-gpio@vger•kernel.org, yamada.masahiro@socionext•com,
	linus.walleij@linaro•org, linux-pm@vger•kernel.org,
	linux@rasmusvillemoes•dk, linux-kernel@vger•kernel.org,
	morten.tiljeset@prevas•dk, sean.nyekjaer@prevas•dk,
	bgolaszewski@baylibre•com, lukas@wunner•de, geert@linux-m68k•org,
	akpm@linux-foundation•org, preid@electromag•com.au,
	linux-arm-kernel@lists•infradead.org
Subject: Re: [PATCH v16 01/14] bitops: Introduce the for_each_set_clump8 macro
Date: Mon, 7 Oct 2019 11:21:56 +0300	[thread overview]
Message-ID: <20191007082156.GL32742@smile.fi.intel.com> (raw)
In-Reply-To: <c0830858f19c852f6d124395a32410bc645ecd15.1570374078.git.vilhelm.gray@gmail.com>

On Sun, Oct 06, 2019 at 11:10:58AM -0400, William Breathitt Gray wrote:
> This macro iterates for each 8-bit group of bits (clump) with set bits,
> within a bitmap memory region. For each iteration, "start" is set to the
> bit offset of the found clump, while the respective clump value is
> stored to the location pointed by "clump". Additionally, the
> bitmap_get_value8 and bitmap_set_value8 functions are introduced to
> respectively get and set an 8-bit value in a bitmap memory region.

Very much thank you for an update!
I have comments below.

> +/**
> + * bitmap_get_value8 - get an 8-bit value within a memory region

Since it's in find.h I would not collide with bitmap namespace.
How about

	find_and_get_value8()

> + * @addr: address to the bitmap memory region
> + * @start: bit offset of the 8-bit value; must be a multiple of 8
> + *
> + * Returns the 8-bit value located at the @start bit offset within the @addr
> + * memory region.
> + */
> +static inline unsigned long bitmap_get_value8(const unsigned long *addr,
> +					      unsigned long start)
> +{
> +	const size_t index = BIT_WORD(start);
> +	const unsigned long offset = start % BITS_PER_LONG;
> +
> +	return (addr[index] >> offset) & 0xFF;
> +}
> +
> +/**
> + * bitmap_set_value8 - set an 8-bit value within a memory region

	find_and_set_value8()

?

> + * @addr: address to the bitmap memory region
> + * @value: the 8-bit value; values wider than 8 bits may clobber bitmap
> + * @start: bit offset of the 8-bit value; must be a multiple of 8
> + */
> +static inline void bitmap_set_value8(unsigned long *addr, unsigned long value,
> +				     unsigned long start)
> +{
> +	const size_t index = BIT_WORD(start);
> +	const unsigned long offset = start % BITS_PER_LONG;
> +
> +	addr[index] &= ~(0xFF << offset);
> +	addr[index] |= value << offset;
> +}

-- 
With Best Regards,
Andy Shevchenko

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