From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx181.postini.com [74.125.245.181]) by kanga.kvack.org (Postfix) with SMTP id 9BC116B00AE for ; Tue, 7 May 2013 22:41:38 -0400 (EDT) Received: by mail-oa0-f50.google.com with SMTP id l10so1477602oag.23 for ; Tue, 07 May 2013 19:41:37 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1367967522-3934-1-git-send-email-j.glisse@gmail.com> From: KOSAKI Motohiro Date: Tue, 7 May 2013 22:41:17 -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 8:51 PM, Jerome Glisse wrote: > On Tue, May 7, 2013 at 8:47 PM, KOSAKI Motohiro > wrote: >> 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. > > Yes but this allow pages != NULL and FOLL_GET not set and as i said > there is no such user of that yet and this is exactly what i was > trying to use. Why? The following bug_on inhibit both case. >> 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