From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753846AbeDKNtY (ORCPT ); Wed, 11 Apr 2018 09:49:24 -0400 Received: from mail-wr0-f193.google.com ([209.85.128.193]:45960 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753154AbeDKNr4 (ORCPT ); Wed, 11 Apr 2018 09:47:56 -0400 X-Google-Smtp-Source: AIpwx4+Pthq3NVnQYAxnGlxOeP29zwDEPLkf4cVCjUreJEKeP5D9yfPaK9magsrsjq4ekuiao/OnXA== X-ME-Sender: From: Boqun Feng To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Ingo Molnar , Andrea Parri , "Paul E. McKenney" , Boqun Feng Subject: [RFC tip/locking/lockdep v6 12/20] lockdep: Add recursive read locks into dependency graph Date: Wed, 11 Apr 2018 21:51:02 +0800 Message-Id: <20180411135110.9217-13-boqun.feng@gmail.com> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180411135110.9217-1-boqun.feng@gmail.com> References: <20180411135110.9217-1-boqun.feng@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since we have all the fundamental to handle recursive read locks, we now add them into the dependency graph. Signed-off-by: Boqun Feng --- kernel/locking/lockdep.c | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 18eb76189727..45a370438add 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -2102,16 +2102,6 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, if (!check_prev_add_irq(curr, prev, next)) return 0; - /* - * For recursive read-locks we do all the dependency checks, - * but we dont store read-triggered dependencies (only - * write-triggered dependencies). This ensures that only the - * write-side dependencies matter, and that if for example a - * write-lock never takes any other locks, then the reads are - * equivalent to a NOP. - */ - if (next->read == 2 || prev->read == 2) - return 1; /* * Is the -> dependency already present? * @@ -2243,11 +2233,7 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) u16 distance = curr->lockdep_depth - depth + 1; hlock = curr->held_locks + depth - 1; - /* - * Only non-recursive-read entries get new dependencies - * added: - */ - if (hlock->read != 2 && hlock->check) { + if (hlock->check) { int ret = check_prev_add(curr, hlock, next, distance, &trace, save_trace); if (!ret) return 0; -- 2.16.2