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 X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 154F1C2BB1D for ; Wed, 15 Apr 2020 00:48:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E53C020737 for ; Wed, 15 Apr 2020 00:48:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="i1bpkIty" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2634698AbgDOAsF (ORCPT ); Tue, 14 Apr 2020 20:48:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S2634608AbgDOAoM (ORCPT ); Tue, 14 Apr 2020 20:44:12 -0400 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 628E8C061A0F for ; Tue, 14 Apr 2020 17:44:11 -0700 (PDT) Received: by mail-pg1-x54a.google.com with SMTP id h16so1332455pgb.16 for ; Tue, 14 Apr 2020 17:44:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=UjNERNq8Aq8bZu5IIILXtpvcau9meFsW7FMuBohne+g=; b=i1bpkItyD1E346kP/89xta90B+TuHGZiUbt/x3MIvq+bvW15lb05O4/lQkdPiJ9NGQ 93sLq3bZ0gCmmBs2NzvanaM5+i/dlvyVeSpkp5CAVl26E/vZDbirlDxpFHnFoGt0asff De+h6ZaWm9zwZliT9jPHTLXv7N8vr/JVd3LV7PLjsPYaE5eCL7pyvWG7c/boM6S6SiQ8 DL83Mwca9qPVHPySOD3QPy0y9xpjNuXuzHvASgjvTwBAnYeenWMlqJp7UjOd4mpJU6bD EkyJRDjvpgKhXJbcQIC6wQknfksS4JPa7DaDbZInnGYHQ5aD/8fgByYqhQqtygZa3D/6 Fi5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=UjNERNq8Aq8bZu5IIILXtpvcau9meFsW7FMuBohne+g=; b=W1Za0uKJZZDKAzTOr+B+a2VsCbqA0FO04uhWQnXZ8o4eOxBlXwNkBFrYhazBt+paCp MFgMDNQnhkGh3KrTBzH4UzfVMDw+xKGeAnSYoINT2UmNBxwfdzYSumds+KCl957WvrYa FPgNHr48j44YEawIzNUhr01QGs787dhta9rrMR7PZqU/oMHo1/TxkrksWMqtQKLjMgwC xI20iCQx41lwFjvYulYO5jdKe/el/l0BZDL7+iYfdviFPl7fvLU7t6SabJEXed8TK4yG FUWvVHs9SL4K5rXkEu7QuqfzEAs2vcqpq+EP0ynXMXlz5bHXZh35Drq5vO+HzmQC1nU2 hr5g== X-Gm-Message-State: AGi0Pua9rFuQZqGhP0HMZoqB0dt58K7WuJVowy+G3b0IkROiUsO7aaNm xV4wEcndwEkiryiaHWW5a7W8pM8c9eM= X-Google-Smtp-Source: APiQypJbfrDGo32N0kQWg0rjiAGglPFM6uGFD1dgxEVO66T2nAcht+qTohafqDdYOoPPr9VCwJjI0Buz46A= X-Received: by 2002:a63:4625:: with SMTP id t37mr23188575pga.83.1586911450839; Tue, 14 Apr 2020 17:44:10 -0700 (PDT) Date: Tue, 14 Apr 2020 17:43:49 -0700 In-Reply-To: <20200415004353.130248-1-walken@google.com> Message-Id: <20200415004353.130248-7-walken@google.com> Mime-Version: 1.0 References: <20200415004353.130248-1-walken@google.com> X-Mailer: git-send-email 2.26.0.110.g2183baf09c-goog Subject: [PATCH v4 06/10] mmap locking API: convert nested write lock sites From: Michel Lespinasse To: Andrew Morton , linux-mm Cc: LKML , Peter Zijlstra , Laurent Dufour , Vlastimil Babka , Matthew Wilcox , Liam Howlett , Jerome Glisse , Davidlohr Bueso , David Rientjes , Hugh Dickins , Ying Han , Jason Gunthorpe , Daniel Jordan , Michel Lespinasse Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add API for nested write locks and convert the few call sites doing that. Signed-off-by: Michel Lespinasse --- arch/um/include/asm/mmu_context.h | 3 ++- include/linux/mmap_lock.h | 5 +++++ kernel/fork.c | 2 +- 3 files changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/um/include/asm/mmu_context.h b/arch/um/include/asm/mmu_context.h index 62262c5c7785..07e1cb53a89f 100644 --- a/arch/um/include/asm/mmu_context.h +++ b/arch/um/include/asm/mmu_context.h @@ -8,6 +8,7 @@ #include #include +#include #include @@ -47,7 +48,7 @@ static inline void activate_mm(struct mm_struct *old, struct mm_struct *new) * when the new ->mm is used for the first time. */ __switch_mm(&new->context.id); - down_write_nested(&new->mmap_sem, 1); + mmap_write_lock_nested(new, 1); uml_setup_stubs(new); mmap_write_unlock(new); } diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h index 8b5a3cd56118..9d34b0690403 100644 --- a/include/linux/mmap_lock.h +++ b/include/linux/mmap_lock.h @@ -11,6 +11,11 @@ static inline void mmap_write_lock(struct mm_struct *mm) down_write(&mm->mmap_sem); } +static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass) +{ + down_write_nested(&mm->mmap_sem, subclass); +} + static inline int mmap_write_lock_killable(struct mm_struct *mm) { return down_write_killable(&mm->mmap_sem); diff --git a/kernel/fork.c b/kernel/fork.c index 9a2511a6714f..bdb5ec3574eb 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -499,7 +499,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, /* * Not linked in yet - no deadlock potential: */ - down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); + mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING); /* No ordering required: file already has been exposed. */ RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm)); -- 2.26.0.110.g2183baf09c-goog