Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753332AbeAIVk1 (ORCPT + 1 other); Tue, 9 Jan 2018 16:40:27 -0500 Received: from mail-it0-f65.google.com ([209.85.214.65]:42400 "EHLO mail-it0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752270AbeAIVkZ (ORCPT ); Tue, 9 Jan 2018 16:40:25 -0500 X-Google-Smtp-Source: ACJfBouILGl79wV6SIVuw24eOs3iNsHgT8Tvny2ZMODszQPJsVUMwxngc897My+MQHxute7qRaLzEA== Date: Tue, 9 Jan 2018 13:40:21 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Andrew Morton cc: Michal Hocko , Andrea Arcangeli , Benjamin Herrenschmidt , Paul Mackerras , Oded Gabbay , Alex Deucher , =?UTF-8?Q?Christian_K=C3=B6nig?= , David Airlie , Joerg Roedel , Doug Ledford , Jani Nikula , Mike Marciniszyn , Sean Hefty , Dimitri Sivanich , Boris Ostrovsky , =?UTF-8?Q?J=C3=A9r=C3=B4me_Glisse?= , Paolo Bonzini , =?UTF-8?Q?Radim_Kr=C4=8Dm=C3=A1=C5=99?= , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [patch -mm] mm, mmu_notifier: annotate mmu notifiers with blockable invalidate callbacks fix fix In-Reply-To: <20171215150429.f68862867392337f35a49848@linux-foundation.org> Message-ID: References: <20171215150429.f68862867392337f35a49848@linux-foundation.org> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Fix mmu_notifier.h comments in "mm, mmu_notifier: annotate mmu notifiers with blockable invalidate callbacks". mmu_notifier_invalidate_range_end() can also call the invalidate_range() callback, so it must not block for MMU_INVALIDATE_DOES_NOT_BLOCK to be set. Also remove a bogus comment about invalidate_range() always being called under the ptl spinlock. Signed-off-by: David Rientjes --- include/linux/mmu_notifier.h | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -34,8 +34,8 @@ struct mmu_notifier_ops { * Flags to specify behavior of callbacks for this MMU notifier. * Used to determine which context an operation may be called. * - * MMU_INVALIDATE_DOES_NOT_BLOCK: invalidate_{start,end} does not - * block + * MMU_INVALIDATE_DOES_NOT_BLOCK: invalidate_range_* callbacks do not + * block */ int flags; @@ -151,8 +151,9 @@ struct mmu_notifier_ops { * address space but may still be referenced by sptes until * the last refcount is dropped. * - * If both of these callbacks cannot block, mmu_notifier_ops.flags - * should have MMU_INVALIDATE_DOES_NOT_BLOCK set. + * If both of these callbacks cannot block, and invalidate_range + * cannot block, mmu_notifier_ops.flags should have + * MMU_INVALIDATE_DOES_NOT_BLOCK set. */ void (*invalidate_range_start)(struct mmu_notifier *mn, struct mm_struct *mm, @@ -175,12 +176,13 @@ struct mmu_notifier_ops { * external TLB range needs to be flushed. For more in depth * discussion on this see Documentation/vm/mmu_notifier.txt * - * The invalidate_range() function is called under the ptl - * spin-lock and not allowed to sleep. - * * Note that this function might be called with just a sub-range * of what was passed to invalidate_range_start()/end(), if * called between those functions. + * + * If this callback cannot block, and invalidate_range_{start,end} + * cannot block, mmu_notifier_ops.flags should have + * MMU_INVALIDATE_DOES_NOT_BLOCK set. */ void (*invalidate_range)(struct mmu_notifier *mn, struct mm_struct *mm, unsigned long start, unsigned long end);