From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mga11.intel.com ([192.55.52.93]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qLNrD-0043MZ-0f for linux-arm-kernel@lists.infradead.org; Mon, 17 Jul 2023 13:03:40 +0000 Date: Mon, 17 Jul 2023 16:01:14 +0300 From: Andy Shevchenko Subject: Re: [PATCH v3 1/5] lib/bitmap: add bitmap_{set,get}_value() Message-ID: References: <20230717113709.328671-1-glider@google.com> <20230717113709.328671-2-glider@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230717113709.328671-2-glider@google.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+lwn-linux-arm-kernel=archive.lwn.net@lists.infradead.org List-Archive: To: Alexander Potapenko Cc: catalin.marinas@arm.com, will@kernel.org, pcc@google.com, andreyknvl@gmail.com, linux@rasmusvillemoes.dk, yury.norov@gmail.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, eugenis@google.com, syednwaris@gmail.com, william.gray@linaro.org, Arnd Bergmann On Mon, Jul 17, 2023 at 01:37:04PM +0200, Alexander Potapenko wrote: > The two new functions allow setting/getting values of length up to > BITS_PER_LONG bits at arbitrary position in the bitmap. > > The code was taken from "bitops: Introduce the for_each_set_clump macro" > by Syed Nayyar Waris with a couple of minor changes: Since changes are minor, please make sure that the authorship is kept untouched. > - instead of using roundup(), which adds an unnecessary dependency > on , we calculate space as BITS_PER_LONG-offset; > - indentation is reduced by not using else-clauses (suggested by > checkpatch for bitmap_get_value()) > Cc: Arnd Bergmann You can use --cc to `git send-email` instead of polluting the commit message. > Signed-off-by: Syed Nayyar Waris > Signed-off-by: William Breathitt Gray > Link: https://lore.kernel.org/lkml/fe12eedf3666f4af5138de0e70b67a07c7f40338.1592224129.git.syednwaris@gmail.com/ > Suggested-by: Yury Norov > Signed-off-by: Alexander Potapenko With above, I think you can also add Co-developed-by (as the changes were made). ... > +static inline void bitmap_set_value(unsigned long *map, > + unsigned long value, > + unsigned long start, unsigned long nbits) > +{ > + const size_t index = BIT_WORD(start); > + const unsigned long offset = start % BITS_PER_LONG; > + const unsigned long space = BITS_PER_LONG - offset; > + > + value &= GENMASK(nbits - 1, 0); > + > + if (space >= nbits) { > + map[index] &= ~(GENMASK(nbits + offset - 1, offset)); I remember that this construction may bring horrible code on some architectures with some version(s) of the compiler (*). To fix that I found an easy refactoring: map[index] &= ~(GENMASK(nbits, 0) << offset)); (*) don't remember the actual versions, though, but anyway... > + map[index] |= value << offset; > + return; > + } > + map[index] &= ~BITMAP_FIRST_WORD_MASK(start); > + map[index] |= value << offset; > + map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + nbits); > + map[index + 1] |= (value >> space); > +} -- With Best Regards, Andy Shevchenko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel