From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754068Ab0I3Dut (ORCPT ); Wed, 29 Sep 2010 23:50:49 -0400 Received: from mail-iw0-f174.google.com ([209.85.214.174]:56474 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753997Ab0I3Duq (ORCPT ); Wed, 29 Sep 2010 23:50:46 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; b=rta5HvddJKmlEPh92ve4HldwhowvRAtPHgPi6nK4xljtBc2WJ7eymhRnVYZXoLTayc zNa0YbcipHIcyDJRueRZfOowcSYbNssSMW65XhgEPbKMPULX2jhMZzQ8VVuJ+nyRL9/y VYQ5+poSTACzCU5w3z2Pg+GPdxTAK/3QsP2Ys= From: Namhyung Kim To: Andrew Morton , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH 06/12] rmap: annotate lock context change on page_[un]lock_anon_vma() Date: Thu, 30 Sep 2010 12:50:15 +0900 Message-Id: <1285818621-29890-7-git-send-email-namhyung@gmail.com> X-Mailer: git-send-email 1.7.2.2 In-Reply-To: <1285818621-29890-1-git-send-email-namhyung@gmail.com> References: <1285818621-29890-1-git-send-email-namhyung@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The page_lock_anon_vma() conditionally grabs RCU and anon_vma lock but page_unlock_anon_vma() releases them unconditionally. This leads sparse to complain about context imbalance. Annotate them. Signed-off-by: Namhyung Kim --- include/linux/rmap.h | 15 ++++++++++++++- mm/rmap.c | 4 +++- 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 31b2fd7..0fa7769 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -230,7 +230,20 @@ int try_to_munlock(struct page *); /* * Called by memory-failure.c to kill processes. */ -struct anon_vma *page_lock_anon_vma(struct page *page); +struct anon_vma *__page_lock_anon_vma(struct page *page); + +static inline struct anon_vma *page_lock_anon_vma(struct page *page) +{ + struct anon_vma *anon_vma; + + __cond_lock(RCU, anon_vma = __page_lock_anon_vma(page)); + + /* (void) is needed to make gcc happy */ + (void) __cond_lock(&anon_vma->root->lock, anon_vma); + + return anon_vma; +} + void page_unlock_anon_vma(struct anon_vma *anon_vma); int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma); diff --git a/mm/rmap.c b/mm/rmap.c index 9d2ba01..244ff06 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -314,7 +314,7 @@ void __init anon_vma_init(void) * Getting a lock on a stable anon_vma from a page off the LRU is * tricky: page_lock_anon_vma rely on RCU to guard against the races. */ -struct anon_vma *page_lock_anon_vma(struct page *page) +struct anon_vma *__page_lock_anon_vma(struct page *page) { struct anon_vma *anon_vma, *root_anon_vma; unsigned long anon_mapping; @@ -348,6 +348,8 @@ out: } void page_unlock_anon_vma(struct anon_vma *anon_vma) + __releases(&anon_vma->root->lock) + __releases(RCU) { anon_vma_unlock(anon_vma); rcu_read_unlock(); -- 1.7.2.2