Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755243Ab1EYHKr (ORCPT ); Wed, 25 May 2011 03:10:47 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:41145 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751974Ab1EYHKq (ORCPT ); Wed, 25 May 2011 03:10:46 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Message-ID: <4DDCAB6B.8060804@jp.fujitsu.com> Date: Wed, 25 May 2011 16:10:35 +0900 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; ja; rv:1.9.2.17) Gecko/20110414 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: kosaki.motohiro@jp.fujitsu.com CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org, aarcange@redhat.com, akpm@linux-foundation.org, n-horiguchi@ah.jp.nec.com, kamezawa.hiroyu@jp.fujitsu.com Subject: [PATCH 3/4] pagewalk: add locking-rule commnets References: <4DDCAAC0.20102@jp.fujitsu.com> In-Reply-To: <4DDCAAC0.20102@jp.fujitsu.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1779 Lines: 49 Originally, walk_hugetlb_range() didn't require a caller take any lock. But commit d33b9f45bd (mm: hugetlb: fix hugepage memory leak in walk_page_range) changed its rule. Because it added find_vma() call in walk_hugetlb_range(). Any locking-rule change commit should write a doc too. Signed-off-by: KOSAKI Motohiro --- include/linux/mm.h | 1 + mm/pagewalk.c | 3 +++ 2 files changed, 4 insertions(+), 0 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index dd87a78..7337b66 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -921,6 +921,7 @@ unsigned long unmap_vmas(struct mmu_gather **tlb, * @pte_entry: if set, called for each non-empty PTE (4th-level) entry * @pte_hole: if set, called for each hole at all levels * @hugetlb_entry: if set, called for each hugetlb entry + * *Caution*: The caller must hold mmap_sem() if it's used. * * (see walk_page_range for more details) */ diff --git a/mm/pagewalk.c b/mm/pagewalk.c index ee4ff87..f792940 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -181,6 +181,9 @@ static int walk_hugetlb_range(struct vm_area_struct *vma, * * If any callback returns a non-zero value, the walk is aborted and * the return value is propagated back to the caller. Otherwise 0 is returned. + * + * walk->mm->mmap_sem must be held for at least read if walk->hugetlb_entry + * is !NULL. */ int walk_page_range(unsigned long addr, unsigned long end, struct mm_walk *walk) -- 1.7.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/