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 X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 57A33C433E0 for ; Thu, 25 Feb 2021 20:26:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E9ED64F1B for ; Thu, 25 Feb 2021 20:26:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233644AbhBYU0G (ORCPT ); Thu, 25 Feb 2021 15:26:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232290AbhBYUZY (ORCPT ); Thu, 25 Feb 2021 15:25:24 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3388C06174A; Thu, 25 Feb 2021 12:24:43 -0800 (PST) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1614284679; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=qDVKAKnnfPFs0Dxv5+kX2VVyNzrYE33K+BDYTVeJME8=; b=Itg1HgnAQey3puEfZXpKRRf1RkHbrPWXsodppd3f9/agHLs59mQxmZvHrDVfXhn7TF2e+X YgctQb8llo4ek4IXOH40pHKrSlSJUv+qmqSuRbNPlwERu5vmF3/VXIexN4FpY+8WHM5d4n 3zHVITkWvbjhosz0zzfOytwQyTccmRTsG9uKDQ/PoVKslKdevkHeAS8FY/vBbTk7ZYAmwx j9C6lcv4wUAstQLOYdbQOINDWx2UjXbjMRmTNEt/9KnzbRIvSmj2EXQuCLrXAd5jyQHGnB 6degQSHuHB1F0v3eFX0HxngBtbRJympKrqQjrUQzvVBIk1MNI805LQYIDMpUAg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1614284679; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=qDVKAKnnfPFs0Dxv5+kX2VVyNzrYE33K+BDYTVeJME8=; b=R+fgiTn80NtyboUkoI+34S01BUhJK8k4MSy2VNzuYCNOKjN83g0YvSMQCLvesqnrTwxeYZ t+PogSzB5duz2fCg== To: Petr Mladek Cc: Sergey Senozhatsky , Sergey Senozhatsky , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, Jeff Dike , Richard Weinberger , Anton Ivanov , Thomas Meyer , Andy Shevchenko , linux-um@lists.infradead.org, Miquel Raynal , Vignesh Raghavendra , linux-mtd@lists.infradead.org, Pavel Tatashin , Kees Cook , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Jason Wessel , Daniel Thompson , Douglas Anderson , Jordan Niethe , Alistair Popple , Ravi Bangoria , Nicholas Piggin , Madhavan Srinivasan , Mike Rapoport , Sumit Garg , Davidlohr Bueso , Wei Li , linuxppc-dev@lists.ozlabs.org, kgdb-bugreport@lists.sourceforge.net, "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Wei Liu , Anton Vorontsov , Colin Cross , Tony Luck , Joel Stanley , Christophe Leroy , Oleg Nesterov , Michael Kelley , linux-hyperv@vger.kernel.org Subject: [PATCH next v3 00/15] printk: remove logbuf_lock Date: Thu, 25 Feb 2021 21:24:23 +0100 Message-Id: <20210225202438.28985-1-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Here is v3 of a series to remove @logbuf_lock, exposing the ringbuffer locklessly to both readers and writers. v2 is here [0]. Since @logbuf_lock was protecting much more than just the ringbuffer, this series clarifies and cleans up the various protections using comments, lockless accessors, atomic types, and a new finer-grained @syslog_lock. Removing @logbuf_lock required changing the semantics of the kmsg_dumper callback in order to work locklessly. Since this involved touching all the kmsg_dump users, we also decided [1] to use this opportunity to clean up and clarify the kmsg_dump semantics in general. This series is based on next-20210225. Changes since v2: - use get_maintainer.pl to get the full list of developers that should at least see the changes in their respective areas - do not disable interrupts in arch/um kmsg_dumper (because there is no need to) - protect the mtd/mtdoops kmsg_dumper buffer against concurrent dumps - update kerneldoc for kmsg_dump_get_line() (@len_out) - remove ksmg_dump's @active flag - change kmsg_dumper callback to: void (*dump)(enum kmsg_dump_reason reason); - rename kmsg_dumper_iter to kmsg_dump_iter - update kmsg_dumpers to use their own kmsg_dump_iter (and initialize it with kmsg_dump_rewind() if necessary) John Ogness [0] https://lkml.kernel.org/r/20210218081817.28849-1-john.ogness@linutronix.de [1] https://lkml.kernel.org/r/YDeZAA08NKCHa4s%2F@alley John Ogness (15): um: synchronize kmsg_dumper mtd: mtdoops: synchronize kmsg_dumper printk: limit second loop of syslog_print_all printk: kmsg_dump: remove unused fields printk: refactor kmsg_dump_get_buffer() printk: consolidate kmsg_dump_get_buffer/syslog_print_all code printk: introduce CONSOLE_LOG_MAX for improved multi-line support printk: use seqcount_latch for clear_seq printk: use atomic64_t for devkmsg_user.seq printk: add syslog_lock printk: kmsg_dumper: remove @active field printk: introduce a kmsg_dump iterator printk: remove logbuf_lock printk: kmsg_dump: remove _nolock() variants printk: console: remove unnecessary safe buffer usage arch/powerpc/kernel/nvram_64.c | 14 +- arch/powerpc/platforms/powernv/opal-kmsg.c | 3 +- arch/powerpc/xmon/xmon.c | 6 +- arch/um/kernel/kmsg_dump.c | 15 +- drivers/hv/vmbus_drv.c | 7 +- drivers/mtd/mtdoops.c | 20 +- fs/pstore/platform.c | 8 +- include/linux/kmsg_dump.h | 49 +-- kernel/debug/kdb/kdb_main.c | 10 +- kernel/printk/internal.h | 4 +- kernel/printk/printk.c | 456 ++++++++++----------- kernel/printk/printk_safe.c | 27 +- 12 files changed, 309 insertions(+), 310 deletions(-) -- 2.20.1