Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 3 Oct 2018 14:48:04 +0300
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc:     William Breathitt Gray <vilhelm.gray@gmail.com>,
        linus.walleij@linaro.org, akpm@linux-foundation.org,
        linux-gpio@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [RESEND PATCH v4 1/8] bitops: Introduce the for_each_set_clump
 macro
Message-ID: <20181003114804.GE15943@smile.fi.intel.com>
References: <cover.1538441919.git.vilhelm.gray@gmail.com>
 <f5250b9c78377e476667be1b616c86cf573b57dc.1538441919.git.vilhelm.gray@gmail.com>
 <40ecad49-2797-0d30-b52d-a2e6838dc1ab@rasmusvillemoes.dk>
 <20181002082142.GC15943@smile.fi.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20181002082142.GC15943@smile.fi.intel.com>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Oct 02, 2018 at 11:21:42AM +0300, Andy Shevchenko wrote:

> I would rather go with two prototypes to get()/set() a clump in the bitmap
> in a way when it's aligned and BITS_PER_LONG % clump_size == 0.

To make things much easier, restrict clump_size to the one
from the following set:

1, 2, 4, 8, 16, 32 even on 64-bit platforms.

If it would be simpler solution to add 64 here (implying 32-bit platform),
I would vote for that.

For the generic case we might need something like:

unsigned long bitmap_get_bits(unsigned long *src, unsigned int start, unsigned int nbits)
{
	assert(nbits > BITS_PER_LONG);

	/* Something like Rasmus proposed earlier */
}

And similar to setter.


-- 
With Best Regards,
Andy Shevchenko