From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754686AbYJFOhH (ORCPT ); Mon, 6 Oct 2008 10:37:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752664AbYJFOg4 (ORCPT ); Mon, 6 Oct 2008 10:36:56 -0400 Received: from nf-out-0910.google.com ([64.233.182.187]:56098 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752591AbYJFOgz (ORCPT ); Mon, 6 Oct 2008 10:36:55 -0400 From: "Kirill A. Shutemov" To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: "Kirill A. Shutemov" , Andi Kleen , Ingo Molnar , Arjan van de Ven , Andrew Morton Subject: [PATCH, RFC] shmat: introduce flag SHM_MAP_HINT Date: Mon, 6 Oct 2008 17:37:59 +0300 Message-Id: <1223303879-5555-1-git-send-email-kirill@shutemov.name> X-Mailer: git-send-email 1.5.6.5.GIT In-Reply-To: <20081006132651.GG3180@one.firstfloor.org> References: <20081006132651.GG3180@one.firstfloor.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It allows interpret attach address as a hint, not as exact address. Signed-off-by: Kirill A. Shutemov Cc: Andi Kleen Cc: Ingo Molnar Cc: Arjan van de Ven Cc: Andrew Morton --- include/linux/shm.h | 1 + ipc/shm.c | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/include/linux/shm.h b/include/linux/shm.h index eca6235..2a637b8 100644 --- a/include/linux/shm.h +++ b/include/linux/shm.h @@ -55,6 +55,7 @@ struct shmid_ds { #define SHM_RND 020000 /* round attach address to SHMLBA boundary */ #define SHM_REMAP 040000 /* take-over region on attach */ #define SHM_EXEC 0100000 /* execution access */ +#define SHM_MAP_HINT 0200000 /* interpret attach address as a hint */ /* super user shmctl commands */ #define SHM_LOCK 11 diff --git a/ipc/shm.c b/ipc/shm.c index e77ec69..19462bb 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -819,7 +819,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) if (shmid < 0) goto out; else if ((addr = (ulong)shmaddr)) { - if (addr & (SHMLBA-1)) { + if (!(shmflg & SHM_MAP_HINT) && (addr & (SHMLBA-1))) { if (shmflg & SHM_RND) addr &= ~(SHMLBA-1); /* round down */ else @@ -828,7 +828,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) #endif goto out; } - flags = MAP_SHARED | MAP_FIXED; + flags = (shmflg & SHM_MAP_HINT ? 0 : MAP_FIXED) | MAP_SHARED; } else { if ((shmflg & SHM_REMAP)) goto out; -- 1.5.6.5.GIT