From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx194.postini.com [74.125.245.194]) by kanga.kvack.org (Postfix) with SMTP id EBD0E6B0068 for ; Tue, 7 May 2013 20:47:29 -0400 (EDT) Received: by mail-ob0-f171.google.com with SMTP id v19so1199841obq.2 for ; Tue, 07 May 2013 17:47:29 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1367967522-3934-1-git-send-email-j.glisse@gmail.com> References: <1367967522-3934-1-git-send-email-j.glisse@gmail.com> From: KOSAKI Motohiro Date: Tue, 7 May 2013 20:47:08 -0400 Message-ID: Subject: Re: [PATCH] mm: honor FOLL_GET flag in follow_hugetlb_page v2 Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Jerome Glisse Cc: "linux-mm@kvack.org" , LKML , Jerome Glisse On Tue, May 7, 2013 at 6:58 PM, wrote: > From: Jerome Glisse > > Do not increase page count if FOLL_GET is not set. None of the > current user can trigger the issue because none of the current > user call __get_user_pages with both the pages array ptr non > NULL and the FOLL_GET flags non set in other word all caller > of __get_user_pages that don't set the FOLL_GET flags also call > with pages == NULL. Because, __get_user_pages() doesn't allow pages==NULL and FOLL_GET is on. long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, { (snip) VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET)); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org