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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67AF6C433F5 for ; Mon, 3 Oct 2022 21:45:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229643AbiJCVpW (ORCPT ); Mon, 3 Oct 2022 17:45:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229639AbiJCVpM (ORCPT ); Mon, 3 Oct 2022 17:45:12 -0400 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ED64114D16 for ; Mon, 3 Oct 2022 14:45:10 -0700 (PDT) Received: by mail-pj1-x1049.google.com with SMTP id o91-20020a17090a0a6400b0020a72db3b87so2361053pjo.5 for ; Mon, 03 Oct 2022 14:45:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date; bh=PIwBsFUD4Ot2l3U8sW+vVhpIiC7Hv9NlG7rycXRX2po=; b=WsbC16muix309bhmioqs8JVwvNFkkMDaq54hdAngB8qg74k12aNlX6m/jXFMQw68Hz xVdkbG/ox1TVUu9nPM959l5QO3b6uQ6SG8nwNtEsjG+Fba0urh7pfpFBsSr0KQo7UTRv fi9Wxr24Uz0rV/L0Eu0d7tl7xsJG8BEtBIJRQ3yGNjqqgh8GGP6Bh0HQF92m0AET+xEF qG+JSm+fjRRyLHvXxJA7lgMyknnmmpKiApT5nnBiKYGFtKHEHjpH452HGTbr6qeTMVec Q2io8QnU5YKsXKxhaOTV5C4NEKCYPTnWGSwhGS7yt+J3gFr76dMsmQMTnhgx68mtEC6/ 8VeA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date; bh=PIwBsFUD4Ot2l3U8sW+vVhpIiC7Hv9NlG7rycXRX2po=; b=Eg6+zd1NjKp40xNCvLjH0vyavsDzqCbOVbbpjmFzWBJmPlTHTAusAAex5rKSo0AetA kHGZTE36FpTyJqlC+eue5w4drq7PWc0+8uW05Wh1/B63FzcpRJzfKPqX0sQN12QhR5Y7 ZG/cMM37j5P1QHyJ8bvEJFiuUGFuPHr3jxtdc1GlkPUGXCzSwjT0a9ObAlepNQqinrXk PJGsIO3cWdpmQ4UqsQmp9olT3Tg28pRuaeO1Vg/DVnnff6RVe2zu628NGA1eUEMuwobN rFIDUA8BUF7oMg2IhgcyWzEkr4erZvN6JQuyCXJCR10QwI1XTfeQai2Nuc3OdM4Ok12S OnXg== X-Gm-Message-State: ACrzQf02XpNAZpXUKmm3wk7d6aaWWEdOBPRCzE4qnMcAruOziztyNlVP wbmaLRaOjnT/KzesmSFVEX4c2DPG2IHh+JkPkdE2Oa9AZpZm1wkEeRUfawK9ZLNrxTRhfB0Gulp smV3v2b0DvII6HwFnaW30NHlOHJvz4xZfl5eYHmjcrB5Vdt8Md+6yBxSml7sMYo1GnvpsfBsp X-Google-Smtp-Source: AMsMyM6jVzjtgYcqJCYTAYXYgBMFEx+HLsCSl+XDfyDhxM/eLW7+jaVcJDULrhHqZFf4GxgDJ03aimEkdAe1 X-Received: from connoro.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:a99]) (user=connoro job=sendgmr) by 2002:a17:90a:c986:b0:205:f08c:a82b with SMTP id w6-20020a17090ac98600b00205f08ca82bmr65264pjt.1.1664833508580; Mon, 03 Oct 2022 14:45:08 -0700 (PDT) Date: Mon, 3 Oct 2022 21:44:53 +0000 In-Reply-To: <20221003214501.2050087-1-connoro@google.com> Mime-Version: 1.0 References: <20221003214501.2050087-1-connoro@google.com> X-Mailer: git-send-email 2.38.0.rc1.362.ged0d419d3c-goog Message-ID: <20221003214501.2050087-4-connoro@google.com> Subject: [RFC PATCH 03/11] kernel/locking: Add p->blocked_on wrapper From: "Connor O'Brien" To: linux-kernel@vger.kernel.org Cc: kernel-team@android.com, John Stultz , Joel Fernandes , Qais Yousef , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , Will Deacon , Waiman Long , Boqun Feng , "Paul E . McKenney" , "Connor O'Brien" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Valentin Schneider This lets us assert p->blocked_lock is held whenever we access p->blocked_on. XXX: just make a pointer return, so we can also check at get's. Signed-off-by: Valentin Schneider [fix conflicts] Signed-off-by: Connor O'Brien --- include/linux/sched.h | 7 +++++++ kernel/locking/mutex.c | 6 +++--- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index bd995e66d7d6..379e4c052644 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2201,6 +2201,13 @@ static inline int rwlock_needbreak(rwlock_t *lock) #endif } +static inline void set_task_blocked_on(struct task_struct *p, struct mutex *m) +{ + lockdep_assert_held(&p->blocked_lock); + + p->blocked_on = m; +} + static __always_inline bool need_resched(void) { return unlikely(tif_need_resched()); diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index f05cd2d216c7..7800380219db 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -645,7 +645,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas goto err_early_kill; } - current->blocked_on = lock; + set_task_blocked_on(current, lock); set_current_state(state); trace_contention_begin(lock, LCB_F_MUTEX); for (;;) { @@ -686,7 +686,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas /* * Gets reset by ttwu_runnable(). */ - current->blocked_on = lock; + set_task_blocked_on(current, lock); set_current_state(state); /* * Here we order against unlock; we must either see it change @@ -720,7 +720,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas } __mutex_remove_waiter(lock, &waiter); - current->blocked_on = NULL; + set_task_blocked_on(current, NULL); debug_mutex_free_waiter(&waiter); -- 2.38.0.rc1.362.ged0d419d3c-goog