From patchwork Wed Apr 21 09:54:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johan Hovold X-Patchwork-Id: 426128 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56C08C43461 for ; Wed, 21 Apr 2021 09:55:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 23C5261456 for ; Wed, 21 Apr 2021 09:55:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238627AbhDUJ4K (ORCPT ); Wed, 21 Apr 2021 05:56:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:52318 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238563AbhDUJ4J (ORCPT ); Wed, 21 Apr 2021 05:56:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 134C86144B; Wed, 21 Apr 2021 09:55:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618998936; bh=D3CiZX5cVcDl+OdheHA4iQdvFSnetaDLj4pdQr4SlmI=; h=From:To:Cc:Subject:Date:From; b=ITKL0SF+lC1Kq/ARs1TaBsjht6azC17JSZBAkLXqYAjp2IyFZwhmvFyysvzxQr0hv spgu8aCxi6opSChVFrKNI/mly72VrGVdAGeWwjeo5AV/PsQRUUkDEiELMOxa8/ExUp OiBqcHcoC/CHlVI4vs4CUPMqYFRhAZihjBMjSFrYqsB5ewj8ol+OPlbu68LPVsT1oM wqhLhJHGYwMHRa4eORehaOkNT7C75ogKLb2ecZcn2QSGwLRsgVRxmHcrWTGZgAvRsW UcE2rqRNt5noA8Dp7/OrzdA63E+zP8QmuF9RF5fkrP2Mb98lOgavU+ZaVkzOlznB9m 6oV8MrvIjy8aA== Received: from johan by xi.lan with local (Exim 4.93.0.4) (envelope-from ) id 1lZ9a6-0000oI-Lo; Wed, 21 Apr 2021 11:55:38 +0200 From: Johan Hovold To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold Subject: [PATCH 00/26] tty: drop low-latency workarounds Date: Wed, 21 Apr 2021 11:54:43 +0200 Message-Id: <20210421095509.3024-1-johan@kernel.org> X-Mailer: git-send-email 2.26.3 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org The infamous low_latency behaviour of tty_flip_buffer_push(), which meant that data could be pushed to the line discipline immediately instead of being deferred to a work queue, was finally removed in 2014. Since then there's no need for drivers to keep hacks to temporarily drop the port lock during receive processing but this pattern has been reproduced in later added drivers nonetheless. Note that several of these workarounds were added by a series posted in 2013, which ended up being merged despite having completely nonsensical commit messages. As it turned out, it was just the RT patch set which effectively enabled the low_latency flag for serial drivers that did not handle it. There's of course nothing wrong releasing the port lock before calling tty_flip_buffer_push(), and some drivers still do after this series, but let's get rid of the completely unnecessary unlock-and-reacquire pattern. Johan Johan Hovold (26): tty: mxser: drop low-latency workaround serial: altera_jtaguart: drop low-latency workaround serial: altera_uart: drop low-latency workaround serial: amba-pl010: drop low-latency workaround serial: amba-pl011: drop low-latency workaround serial: apbuart: drop low-latency workaround serial: ar933x: drop low-latency workaround serial: arc_uart: drop low-latency workaround serial: atmel_serial: drop low-latency workaround serial: bcm63xx: drop low-latency workaround serial: icom: drop low-latency workaround serial: lpc32xx_hs: drop low-latency workaround serial: mcf: drop low-latency workaround serial: meson: drop low-latency workaround serial: mpc52xx_uart: drop low-latency workaround serial: msm_serial: drop low-latency workaround serial: owl: drop low-latency workaround serial: rda: drop low-latency workaround serial: rp2: drop low-latency workaround serial: sa1100: drop low-latency workaround serial: txx9: drop low-latency workaround serial: sifive: drop low-latency workaround serial: sunsu: drop low-latency workaround serial: timbuart: drop low-latency workaround serial: vt8500: drop low-latency workaround serial: xilinx_uartps: drop low-latency workaround drivers/tty/mxser.c | 7 ------- drivers/tty/serial/altera_jtaguart.c | 2 -- drivers/tty/serial/altera_uart.c | 2 -- drivers/tty/serial/amba-pl010.c | 2 -- drivers/tty/serial/amba-pl011.c | 2 -- drivers/tty/serial/apbuart.c | 2 -- drivers/tty/serial/ar933x_uart.c | 2 -- drivers/tty/serial/arc_uart.c | 2 -- drivers/tty/serial/atmel_serial.c | 18 ------------------ drivers/tty/serial/bcm63xx_uart.c | 2 -- drivers/tty/serial/icom.c | 2 -- drivers/tty/serial/lpc32xx_hs.c | 2 -- drivers/tty/serial/mcf.c | 2 -- drivers/tty/serial/meson_uart.c | 2 -- drivers/tty/serial/mpc52xx_uart.c | 2 -- drivers/tty/serial/msm_serial.c | 4 ---- drivers/tty/serial/owl-uart.c | 2 -- drivers/tty/serial/rda-uart.c | 2 -- drivers/tty/serial/rp2.c | 2 -- drivers/tty/serial/sa1100.c | 2 -- drivers/tty/serial/serial_txx9.c | 4 ++-- drivers/tty/serial/sifive.c | 2 -- drivers/tty/serial/sunsu.c | 4 ---- drivers/tty/serial/timbuart.c | 2 -- drivers/tty/serial/vt8500_serial.c | 2 -- drivers/tty/serial/xilinx_uartps.c | 3 +-- 26 files changed, 3 insertions(+), 77 deletions(-)