From patchwork Tue Apr 18 11:10:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Bara X-Patchwork-Id: 1770072 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=linux-tegra-owner@vger.kernel.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20221208 header.b=WHN88Vc9; dkim-atps=neutral Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by legolas.ozlabs.org (Postfix) with ESMTP id 4Q11SD6kqCz1ybC for ; Tue, 18 Apr 2023 21:10:52 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229721AbjDRLKv (ORCPT ); Tue, 18 Apr 2023 07:10:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231209AbjDRLKl (ORCPT ); Tue, 18 Apr 2023 07:10:41 -0400 Received: from mail-ej1-x62e.google.com (mail-ej1-x62e.google.com [IPv6:2a00:1450:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 903D38A45; Tue, 18 Apr 2023 04:10:27 -0700 (PDT) Received: by mail-ej1-x62e.google.com with SMTP id ud9so71931986ejc.7; Tue, 18 Apr 2023 04:10:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1681816226; x=1684408226; 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=WHN88Vc9KjwSakLtGnGRxSGwAb5hfpAeWjrK647q2A6PsNe5izO5GzkcJPGI6sW6uj jB3D7Irqtyf8vjBNUGd/V5iWbc33CbakCySOYjxTRlG2vwGY74x31/Nrsu/rKr9/4xFT 92cYgR8Bh9Ety6g/cq9dARHDFOqjXBmeFGqwQdzNsTNwlv44D/61gPvXcw9MEUeIPOBS wmNeAvp4LasaHVBPseGpSDFceiHLT9vSdnbCtPtgmuDbOGE0vV4l0Ns3FXceRcZY8k9u WFml/gABit3ZGZtcXwQK9BvXEA+W1gI15Hf6JETIxj6FWY9QezjNL7mcKmYdE5zXwBEd 30ww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681816226; x=1684408226; 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=LE/WloCH2Wq6UpxrwpBwpbVT9GjDzoIQA1LkdBGl3MHIIZoiERHioZI843jkUp7ctp U6QirwDGMN87AX0p//k7Y5E42FT00cwU2Xqsn+UpEOAoD5enL5D8hv9tP/pPXMBKmc8+ 2s2/BrT04GwS5H6hC24GJ7rN0nVR/qCpdvnQJQwDyH60pFN5EVgUlYs8xL1m7FA7fSR9 PYzzycwYW+3d6Kns7WB6OckL1xAxtOtG+PgwwsgOrTuW6cRP9R+4KESQwGF7LyS+OSEE A76zsn4j1wq62XUo4tM6xnmZGwgk7A9kSm6rSRZ2wzmrI1ORcTMU2pat8PSlmzmHQopz 0XSA== X-Gm-Message-State: AAQBX9doFR5taJzWOrrj5VECH8i9ZUAQGwqTj5h+qi1rD8EBYdXerspc 1fa8uNemTJwK/liJSD+VgsC2zsYT3BV/Mr4a X-Google-Smtp-Source: AKy350ZuIdjnhggkyP+eOiGXyizYmsnDJvuabPw9yGecpbmmPdEmaRx0JM48/q9ZC1e4KuZrdXMHYA== X-Received: by 2002:a17:906:240f:b0:94f:1a11:e08b with SMTP id z15-20020a170906240f00b0094f1a11e08bmr9336774eja.20.1681816225496; Tue, 18 Apr 2023 04:10:25 -0700 (PDT) Received: from [127.0.1.1] ([91.230.2.244]) by smtp.gmail.com with ESMTPSA id n26-20020a170906379a00b0094eef800850sm5954554ejc.204.2023.04.18.04.10.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Apr 2023 04:10:25 -0700 (PDT) From: Benjamin Bara Date: Tue, 18 Apr 2023 13:10:01 +0200 Subject: [PATCH v5 2/6] i2c: core: run atomic i2c xfer when !preemptible MIME-Version: 1.0 Message-Id: <20230327-tegra-pmic-reboot-v5-2-ab090e03284d@skidata.com> References: <20230327-tegra-pmic-reboot-v5-0-ab090e03284d@skidata.com> In-Reply-To: <20230327-tegra-pmic-reboot-v5-0-ab090e03284d@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 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-tegra@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 --- 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)