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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 39F17C369A4 for ; Wed, 9 Apr 2025 15:44:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=sG8K4R/Cb7pj1avNyOUDGqzkRMg79U1oYgYnAz/irc4=; b=jZTCUXyUtpBAgb /AezIXgMqUhpC/oX2dCftNEkUHzeKrnomGh8RassnzDRSf1VsRton55zn65gRtOrRx1GyXyxhXi7H SLI49DRFEjLv+8LmXl7gespJp7E7+W7CsFobkodgyBpgP7uVDpi1ZpCy9awqzlY9URJ6IblOEM10b lPD4wUi78kbEf+jhRqUIN6k7ohPoFy0r4Xw5JNiv+eC93KYtE9+HeofVjX2JR9Ke0QQaYS/VXfEKJ VtRgUnpMg+peep2hzLtu2ekU5MyNmSAF4oXLXy0zc8RlkgLpyo6J4xpsdajOK4yh9NKkWoRbXWwh2 KNxxridXUTqZEr9yWX2A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u2XbO-00000007jyk-2QUc; Wed, 09 Apr 2025 15:44:34 +0000 Received: from mail-pj1-x102b.google.com ([2607:f8b0:4864:20::102b]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u2XbM-00000007jxc-24vP; Wed, 09 Apr 2025 15:44:33 +0000 Received: by mail-pj1-x102b.google.com with SMTP id 98e67ed59e1d1-3014678689aso5917240a91.0; Wed, 09 Apr 2025 08:44:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1744213471; x=1744818271; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=MUUuTxOiF/e6pFbiGJ55Vd+VaZOP/yQaXFZJe/XlPzE=; b=MLXtz02Yl34CC2ck/6nWhqDMOuhcz/QPrfoz4fMA1jNDtxxZS/9mmTQEg6qPd/XJFr yIyw+YqaovTj/JygnuGGeRS8le/Oo9GZeQk/dyhpzOSAmiK4dGUwVb6YE79rfaV7rTOy DVaresiODQOJuVdPygKHqmkTTFj731CvNCcJk1QXyXGS+r+b4AiNw0+pTLfNWudW2zVB wrv3Cv3J52skjfzjM7mlI8DEcrUrAuntUgdfN1kob1i3NTA18tA+FgNN9yuDSTAbJefQ /NTkcxt0LBbvigs492mKMlrxtrfUyKS3RPfEPnywqt7v3l7x4bbIYvq/rzl1gNVn+BTS mUGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744213471; x=1744818271; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=MUUuTxOiF/e6pFbiGJ55Vd+VaZOP/yQaXFZJe/XlPzE=; b=DwcNrICQaz8VqpbcSqYUq2paRybwgyuT3z/T8zDzlzew8g/VgDq4IrsNAu+Jmx/k2a I4d/dGoZpcTNjgdbaVjX7s1eevjhPJyyx1Vuz3EH7TBgehK0F+82f4Wh5JZmQWMP48J2 JHhYmL+fu3VOVhT1zKEAmyZIEyH0oJkRzH01InFZOGeSlXtkKMENlXquSMr2KJKXVlj1 7GrAZoEYiUEOodKu+s/y75K7/+9eVhaj3W75U93+AwYcXy/O5UqnZ9qstGWSiR5s3SK/ 3fJIxOFI6gohJYtGwMzh/vsSIGRwrT6ScTPIQyBOVRwVLzDci4vG9boGTY5dgwG9m2+t wsEQ== X-Forwarded-Encrypted: i=1; AJvYcCUUMrt9RmBBOhh4PYvETxNqauyu0zX9BwmFHAp5Gwak0gDLDVyhntPLfNiJzMBwkRtjsO5mYVD1K74=@lists.infradead.org, AJvYcCVeklpr/8rzvoBNMvfS5DvKX33mZNZjsSg28U32CgNq8H7F6pc+SL5ul6spjZfok+CTKJ6tFhDPncLb@lists.infradead.org X-Gm-Message-State: AOJu0YzfFvZR4nNqZMLTOdSWAN9p5odKjBvp3KSJN8kD0SWlAlGRYQWn QGF63kxVJCGjxGDIeuCzQnFNklx8srN9PAplun6j4wC7T/GDPyqu X-Gm-Gg: ASbGnctj/MN3E2V5h34Pdm399w57HdQHCSMgrrW0ka41Q4wDrLiodnkG5xh4ixSwLtE ry2JdVKJJmSVChc4l+vkmhnAfBmeC9YiJRiS5vaSgZekE61GcLNIe3AqLzB5kOQPKJF44Kp2jb3 naEJlDoWYBQ0VG0fk5CjKBogexIPZLTLgcgLnWMCImGHZw3U71Y0EbAsPP6pRxjh2VMJqohRB95 OUz5L14Qx/vXjOvONGH1h0OZxzZQeeix/Yef02dRiNlz1+OL6T1MXvCOEaSteEXjISXix0zY0uq AUO9QSknaGMTcNeOrKyV39uwYIlte6C6YDA/7dAz8UW746tJn7n5KZZi51adDqIYXBCu7yk= X-Google-Smtp-Source: AGHT+IGnoEozOknyoC6We3L6wSu5LW5c8+l3K2S+PrKsnw7nWoi0Lt21fMnvhITP0Puz6RwfcrL34g== X-Received: by 2002:a17:90a:d884:b0:2f9:cf97:56ac with SMTP id 98e67ed59e1d1-306dd1719cfmr5116718a91.0.1744213470998; Wed, 09 Apr 2025 08:44:30 -0700 (PDT) Received: from visitorckw-System-Product-Name.. ([140.113.216.168]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-306dd171991sm1952304a91.37.2025.04.09.08.44.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Apr 2025 08:44:30 -0700 (PDT) From: Kuan-Wei Chiu To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, jk@ozlabs.org, joel@jms.id.au, eajames@linux.ibm.com, andrzej.hajda@intel.com, neil.armstrong@linaro.org, rfoss@kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch, dmitry.torokhov@gmail.com, mchehab@kernel.org, awalls@md.metrocast.net, hverkuil@xs4all.nl, miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com, louis.peens@corigine.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, parthiban.veerasooran@microchip.com, arend.vanspriel@broadcom.com, johannes@sipsolutions.net, gregkh@linuxfoundation.org, jirislaby@kernel.org, yury.norov@gmail.com, akpm@linux-foundation.org, jdelvare@suse.com, linux@roeck-us.net, alexandre.belloni@bootlin.com, pgaj@cadence.com Cc: hpa@zytor.com, alistair@popple.id.au, linux@rasmusvillemoes.dk, Laurent.pinchart@ideasonboard.com, jonas@kwiboo.se, jernej.skrabec@gmail.com, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-fsi@lists.ozlabs.org, dri-devel@lists.freedesktop.org, linux-input@vger.kernel.org, linux-media@vger.kernel.org, linux-mtd@lists.infradead.org, oss-drivers@corigine.com, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, brcm80211@lists.linux.dev, brcm80211-dev-list.pdl@broadcom.com, linux-serial@vger.kernel.org, bpf@vger.kernel.org, jserv@ccns.ncku.edu.tw, Frank.Li@nxp.com, linux-hwmon@vger.kernel.org, linux-i3c@lists.infradead.org, david.laight.linux@gmail.com, andrew.cooper3@citrix.com, Kuan-Wei Chiu , Yu-Chun Lin Subject: [PATCH v4 00/13] Introduce parity_odd() and refactor redundant parity code Date: Wed, 9 Apr 2025 23:43:43 +0800 Message-Id: <20250409154356.423512-1-visitorckw@gmail.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250409_084432_534455_909EF233 X-CRM114-Status: GOOD ( 13.94 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org Several parts of the kernel contain open-coded and redundant implementations of parity calculation. This patch series introduces a unified helper, parity_odd(), to simplify and standardize these cases. The first patch renames parity8() to parity_odd(), changes its argument type from u8 to u64 for broader applicability, and updates its return type from int to bool to make its usage and return semantics more intuitive-returning true for odd parity and false for even parity. It also adds __attribute_const__ to enable compiler optimizations. While more efficient implementations may exist, further optimization is postponed until a use case in performance-critical paths arises. Subsequent patches refactor various kernel components to replace open-coded parity logic with the new helper, reducing code duplication and improving consistency. Co-developed-by: Yu-Chun Lin Signed-off-by: Yu-Chun Lin Signed-off-by: Kuan-Wei Chiu --- To H. Peter: I understand your preference for a parity8/16/32/64() style interface, and I agree that such a design would better accommodate potential arch-specific implementations. However, I suspect there are very few, if any, users who care about the performance of parity calculations enough to warrant such optimizations. So my inclination is to defer any arch-specific or optimized implementations until we see parity_odd() being used in hot paths. Changes in v4: - Rename parity8() to parity_odd(). - Change the argument type from u8 to u64. - Use a single parity_odd() function. Changes in v3: - Avoid using __builtin_parity. - Change return type to bool. - Drop parity() macro. - Change parityXX() << y to !!parityXX() << y. Changes in v2: - Provide fallback functions for __builtin_parity() when the compiler decides not to inline it - Use __builtin_parity() when no architecture-specific implementation is available - Optimize for constant folding when val is a compile-time constant - Add a generic parity() macro - Drop the x86 bootflag conversion patch since it has been merged into the tip tree v3: https://lore.kernel.org/lkml/20250306162541.2633025-1-visitorckw@gmail.com/ v1: https://lore.kernel.org/lkml/20250223164217.2139331-1-visitorckw@gmail.com/ v2: https://lore.kernel.org/lkml/20250301142409.2513835-1-visitorckw@gmail.com/ Kuan-Wei Chiu (13): bitops: Change parity8() to parity_odd() with u64 input and bool return type media: media/test_drivers: Replace open-coded parity calculation with parity_odd() media: pci: cx18-av-vbi: Replace open-coded parity calculation with parity_odd() media: saa7115: Replace open-coded parity calculation with parity_odd() serial: max3100: Replace open-coded parity calculation with parity_odd() lib/bch: Replace open-coded parity calculation with parity_odd() Input: joystick - Replace open-coded parity calculation with parity_odd() net: ethernet: oa_tc6: Replace open-coded parity calculation with parity_odd() wifi: brcm80211: Replace open-coded parity calculation with parity_odd() drm/bridge: dw-hdmi: Replace open-coded parity calculation with parity_odd() mtd: ssfdc: Replace open-coded parity calculation with parity_odd() fsi: i2cr: Replace open-coded parity calculation with parity_odd() nfp: bpf: Replace open-coded parity calculation with parity_odd() arch/x86/kernel/bootflag.c | 4 +-- drivers/fsi/fsi-master-i2cr.c | 20 +++------------ .../drm/bridge/synopsys/dw-hdmi-ahb-audio.c | 8 ++---- drivers/hwmon/spd5118.c | 2 +- drivers/i3c/master/dw-i3c-master.c | 2 +- drivers/i3c/master/i3c-master-cdns.c | 2 +- drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 2 +- drivers/input/joystick/grip_mp.c | 17 ++----------- drivers/input/joystick/sidewinder.c | 25 ++++--------------- drivers/media/i2c/saa7115.c | 12 ++------- drivers/media/pci/cx18/cx18-av-vbi.c | 12 ++------- .../media/test-drivers/vivid/vivid-vbi-gen.c | 8 ++---- drivers/mtd/ssfdc.c | 20 +++------------ drivers/net/ethernet/netronome/nfp/nfp_asm.c | 7 +----- drivers/net/ethernet/oa_tc6.c | 19 +++----------- .../broadcom/brcm80211/brcmsmac/dma.c | 18 ++----------- drivers/tty/serial/max3100.c | 3 ++- include/linux/bitops.h | 19 ++++++++------ lib/bch.c | 14 +---------- 19 files changed, 49 insertions(+), 165 deletions(-) -- 2.34.1 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/