From mboxrd@z Thu Jan 1 00:00:00 1970 From: William Breathitt Gray Subject: Re: [PATCH v16 01/14] bitops: Introduce the for_each_set_clump8 macro Date: Mon, 7 Oct 2019 11:18:51 -0400 Message-ID: <20191007151851.GA3494@icarus> References: <20191007082156.GL32742@smile.fi.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20191007082156.GL32742@smile.fi.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Andy Shevchenko Cc: linus.walleij@linaro.org, bgolaszewski@baylibre.com, akpm@linux-foundation.org, linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux@rasmusvillemoes.dk, yamada.masahiro@socionext.com, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, geert@linux-m68k.org, preid@electromag.com.au, lukas@wunner.de, sean.nyekjaer@prevas.dk, morten.tiljeset@prevas.dk, Arnd Bergmann List-Id: linux-arch.vger.kernel.org On Mon, Oct 07, 2019 at 11:21:56AM +0300, Andy Shevchenko wrote: > 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() We modeled the interface for these on the existing bitmap functions, so perhaps it would be better to move bitmap_get_value8 and bitmap_set_value8 to include/linux/bitmap.h so that they are with the rest of the bitmap functions -- afterall, they are operating on bitmaps. > > + * @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 The find_next_clump8 function can remain exposed via include/linux/find.h since it fits in with the rest of the functions there. The reason I moved the definition to lib/find_bit.c is due to the circular dependency that arose from the round_down macro. Should I try to move the definition back to include/linux/find.h and reimplement it without the round_down macro; or is it best to keep this simpler implementation here in lib/find_bit.c? William Breathitt Gray From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw1-f66.google.com ([209.85.161.66]:46340 "EHLO mail-yw1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727745AbfJGPTK (ORCPT ); Mon, 7 Oct 2019 11:19:10 -0400 Date: Mon, 7 Oct 2019 11:18:51 -0400 From: William Breathitt Gray Subject: Re: [PATCH v16 01/14] bitops: Introduce the for_each_set_clump8 macro Message-ID: <20191007151851.GA3494@icarus> References: <20191007082156.GL32742@smile.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191007082156.GL32742@smile.fi.intel.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Andy Shevchenko Cc: linus.walleij@linaro.org, bgolaszewski@baylibre.com, akpm@linux-foundation.org, linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux@rasmusvillemoes.dk, yamada.masahiro@socionext.com, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, geert@linux-m68k.org, preid@electromag.com.au, lukas@wunner.de, sean.nyekjaer@prevas.dk, morten.tiljeset@prevas.dk, Arnd Bergmann Message-ID: <20191007151851.0ZHNWO_qxEtPVZP6Vxm7e-DBz61UzyiygzEixF2OMW8@z> On Mon, Oct 07, 2019 at 11:21:56AM +0300, Andy Shevchenko wrote: > 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() We modeled the interface for these on the existing bitmap functions, so perhaps it would be better to move bitmap_get_value8 and bitmap_set_value8 to include/linux/bitmap.h so that they are with the rest of the bitmap functions -- afterall, they are operating on bitmaps. > > + * @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 The find_next_clump8 function can remain exposed via include/linux/find.h since it fits in with the rest of the functions there. The reason I moved the definition to lib/find_bit.c is due to the circular dependency that arose from the round_down macro. Should I try to move the definition back to include/linux/find.h and reimplement it without the round_down macro; or is it best to keep this simpler implementation here in lib/find_bit.c? William Breathitt Gray