From nobody Sun Feb 8 05:12:23 2026 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 70A39C77B7C for ; Tue, 9 May 2023 16:57:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234850AbjEIQ51 (ORCPT ); Tue, 9 May 2023 12:57:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234704AbjEIQ5R (ORCPT ); Tue, 9 May 2023 12:57:17 -0400 Received: from out-30.mta1.migadu.com (out-30.mta1.migadu.com [IPv6:2001:41d0:203:375::1e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C94B449C for ; Tue, 9 May 2023 09:57:14 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1683651432; 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: in-reply-to:in-reply-to:references:references; bh=7HXn4Ai3HCc0Fe34KxBMMS4Cno5NneBVwyeI+DfOSZ4=; b=aTfDXF9VG6rJ5VBr/J1ipGa3nA3Clu74t98FmSTVJUFgFARXPIpxAfp1Ovgk+6ZiaUeFjD bH5CLS4lIqmGRgG9Baix4APh2l4XUo2b6AeytH8ospRhzCz+fIjSQqKysb/odZULWx+TVC bs/XLATI6OhaENIAq7yonjl8pTvBAKc= From: Kent Overstreet To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-bcachefs@vger.kernel.org Cc: Kent Overstreet , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng Subject: [PATCH 03/32] locking/lockdep: lockdep_set_no_check_recursion() Date: Tue, 9 May 2023 12:56:28 -0400 Message-Id: <20230509165657.1735798-4-kent.overstreet@linux.dev> In-Reply-To: <20230509165657.1735798-1-kent.overstreet@linux.dev> References: <20230509165657.1735798-1-kent.overstreet@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This adds a method to tell lockdep not to check lock ordering within a lock class - but to still check lock ordering w.r.t. other lock types. This is for bcachefs, where for btree node locks we have our own deadlock avoidance strategy w.r.t. other btree node locks (cycle detection), but we still want lockdep to check lock ordering w.r.t. other lock types. Signed-off-by: Kent Overstreet Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Will Deacon Cc: Waiman Long Cc: Boqun Feng --- include/linux/lockdep.h | 6 ++++++ include/linux/lockdep_types.h | 2 +- kernel/locking/lockdep.c | 26 ++++++++++++++++++++++++++ 3 files changed, 33 insertions(+), 1 deletion(-) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index e858c288c7..f6cc8709e2 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -665,4 +665,10 @@ lockdep_rcu_suspicious(const char *file, const int lin= e, const char *s) } #endif =20 +#ifdef CONFIG_DEBUG_LOCK_ALLOC +void lockdep_set_no_check_recursion(struct lockdep_map *map); +#else +static inline void lockdep_set_no_check_recursion(struct lockdep_map *map)= {} +#endif + #endif /* __LINUX_LOCKDEP_H */ diff --git a/include/linux/lockdep_types.h b/include/linux/lockdep_types.h index d22430840b..506e769b4a 100644 --- a/include/linux/lockdep_types.h +++ b/include/linux/lockdep_types.h @@ -128,7 +128,7 @@ struct lock_class { u8 wait_type_inner; u8 wait_type_outer; u8 lock_type; - /* u8 hole; */ + u8 no_check_recursion; =20 #ifdef CONFIG_LOCK_STAT unsigned long contention_point[LOCKSTAT_POINTS]; diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index e631464070..f022b58dfa 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3024,6 +3024,9 @@ check_deadlock(struct task_struct *curr, struct held_= lock *next) if ((next->read =3D=3D 2) && prev->read) continue; =20 + if (hlock_class(next)->no_check_recursion) + continue; + /* * We're holding the nest_lock, which serializes this lock's * nesting behaviour. @@ -3085,6 +3088,10 @@ check_prev_add(struct task_struct *curr, struct held= _lock *prev, return 2; } =20 + if (hlock_class(prev) =3D=3D hlock_class(next) && + hlock_class(prev)->no_check_recursion) + return 2; + /* * Prove that the new -> dependency would not * create a circular dependency in the graph. (We do this by @@ -6620,3 +6627,22 @@ void lockdep_rcu_suspicious(const char *file, const = int line, const char *s) warn_rcu_exit(rcu); } EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +void lockdep_set_no_check_recursion(struct lockdep_map *lock) +{ + struct lock_class *class =3D lock->class_cache[0]; + unsigned long flags; + + raw_local_irq_save(flags); + lockdep_recursion_inc(); + + if (!class) + class =3D register_lock_class(lock, 0, 0); + if (class) + class->no_check_recursion =3D true; + lockdep_recursion_finish(); + raw_local_irq_restore(flags); +} +EXPORT_SYMBOL_GPL(lockdep_set_no_check_recursion); +#endif --=20 2.40.1