From patchwork Tue May 9 19:03:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Bara X-Patchwork-Id: 680765 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A98B9C7EE2E for ; Tue, 9 May 2023 19:03:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234934AbjEITDp (ORCPT ); Tue, 9 May 2023 15:03:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234635AbjEITDk (ORCPT ); Tue, 9 May 2023 15:03:40 -0400 Received: from mail-ej1-x633.google.com (mail-ej1-x633.google.com [IPv6:2a00:1450:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F27649EE; Tue, 9 May 2023 12:03:39 -0700 (PDT) Received: by mail-ej1-x633.google.com with SMTP id a640c23a62f3a-9661047f8b8so733150266b.0; Tue, 09 May 2023 12:03:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1683659017; x=1686251017; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=WbgVQUp/vUincJRkcsp/7lCVaCrW8ZOrNJHo4G9adBQ=; b=Afvjm2OnP/cD1G79QHO+6f/98CFgsDJipiNhtGgCLQ163WD/TgRIJOCoPI/htLTnM/ mvr/x3KmOS6hUNe2fRTGk+QZUyM5UdwnuHndH0eaaLvqqQxWHo7Nc9RM62YhrKaL67zz kG/Ie8OqEwT4yGD320fK8tpLWgWZulX2hZDCpphgltCOXrmoGuYym6dYM7mh84PGvLrb Y8/Te5E31rPgn0BpzH+2DbpV3T+dFATJXgeS+lANmT3i3+NPQ9EI0QeTZEUlH1BTSnwE Oomukj7VUTvhJ8Rw0y0xyHcHA4Dh7BC8BZRtm+0UCmNHwx8oSX8OtPCiIYhAKp3ZnHqo ywIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683659017; x=1686251017; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=WbgVQUp/vUincJRkcsp/7lCVaCrW8ZOrNJHo4G9adBQ=; b=QFGy5AFP3WRuY/JfA8tv4PWIekrEHLZvD9b2A+HUDk1327RM8w/Z3MHwHEa5FK16xq aORT93GxvYjvJl8oY4d/ceOjIlZLRZSxsIyKnu5lms1wc+3y8+JBcf5GFue+Q/c7kJJV qw1c+J4qoCcBDbOAMfQdn1OsUmY1o3/GnmZBr3SFav5b5H3tvt+P2mkWfhECOceCPpei TTdu+US5mm4KZliZ0xlH2mC/+0tqsuNGpQoU7dWruWgKSIAHxkCGnR6vGjnbogqtHd1t zBhpmKLjav9/M4nCOG3nzqj8bUwPPIujp65Y3p0nHXGge07DqjJDkJRSdfJ2y9HWYfG0 FcRg== X-Gm-Message-State: AC+VfDzA/+aPnppaLI9/pqkEMr2/PEnqt3A5+ttONbH7+P+EG6P6bGH3 QEtYGwtQqwIYU60wNd+hIGyqxKuauNxqWvoh X-Google-Smtp-Source: ACHHUZ7SZPJq43m1vkwSM8OY9Jp1q+dUpgBMGulzGUFY6gKuPbX9x/U6HHzFHCtZEHrXxbptHT4TqQ== X-Received: by 2002:a17:907:3e05:b0:94e:988d:acc5 with SMTP id hp5-20020a1709073e0500b0094e988dacc5mr14025282ejc.46.1683659017415; Tue, 09 May 2023 12:03:37 -0700 (PDT) Received: from [127.0.1.1] ([91.230.2.244]) by smtp.gmail.com with ESMTPSA id e2-20020a170906c00200b009697aa5acfcsm1640232ejz.122.2023.05.09.12.03.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 May 2023 12:03:37 -0700 (PDT) From: Benjamin Bara Date: Tue, 09 May 2023 21:03:00 +0200 Subject: [PATCH v6 2/5] i2c: core: run atomic i2c xfer when !preemptible MIME-Version: 1.0 Message-Id: <20230327-tegra-pmic-reboot-v6-2-af44a4cd82e9@skidata.com> References: <20230327-tegra-pmic-reboot-v6-0-af44a4cd82e9@skidata.com> In-Reply-To: <20230327-tegra-pmic-reboot-v6-0-af44a4cd82e9@skidata.com> To: Wolfram Sang , Lee Jones , rafael.j.wysocki@intel.com Cc: dmitry.osipenko@collabora.com, peterz@infradead.org, jonathanh@nvidia.com, richard.leitner@linux.dev, treding@nvidia.com, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, linux-tegra@vger.kernel.org, Benjamin Bara , stable@vger.kernel.org X-Mailer: b4 0.12.2 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Benjamin Bara Since bae1d3a05a8b, i2c transfers are non-atomic if preemption is disabled. However, non-atomic i2c transfers require preemption (e.g. in wait_for_completion() while waiting for the DMA). panic() calls preempt_disable_notrace() before calling emergency_restart(). Therefore, if an i2c device is used for the restart, the xfer should be atomic. This avoids warnings like: [ 12.667612] WARNING: CPU: 1 PID: 1 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x33c/0x6b0 [ 12.676926] Voluntary context switch within RCU read-side critical section! ... [ 12.742376] schedule_timeout from wait_for_completion_timeout+0x90/0x114 [ 12.749179] wait_for_completion_timeout from tegra_i2c_wait_completion+0x40/0x70 ... [ 12.994527] atomic_notifier_call_chain from machine_restart+0x34/0x58 [ 13.001050] machine_restart from panic+0x2a8/0x32c Use !preemptible() instead, which is basically the same check as pre-v5.2. Fixes: bae1d3a05a8b ("i2c: core: remove use of in_atomic()") Cc: stable@vger.kernel.org # v5.2+ Suggested-by: Dmitry Osipenko Acked-by: Wolfram Sang Signed-off-by: Benjamin Bara Reviewed-by: Dmitry Osipenko --- drivers/i2c/i2c-core.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h index 1247e6e6e975..05b8b8dfa9bd 100644 --- a/drivers/i2c/i2c-core.h +++ b/drivers/i2c/i2c-core.h @@ -29,7 +29,7 @@ int i2c_dev_irq_from_resources(const struct resource *resources, */ static inline bool i2c_in_atomic_xfer_mode(void) { - return system_state > SYSTEM_RUNNING && irqs_disabled(); + return system_state > SYSTEM_RUNNING && !preemptible(); } static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap)