From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755467AbZBUBzS (ORCPT ); Fri, 20 Feb 2009 20:55:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752379AbZBUBzE (ORCPT ); Fri, 20 Feb 2009 20:55:04 -0500 Received: from byss.tchmachines.com ([208.76.80.75]:57048 "EHLO byss.tchmachines.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751779AbZBUBzB (ORCPT ); Fri, 20 Feb 2009 20:55:01 -0500 Date: Fri, 20 Feb 2009 17:54:57 -0800 From: Ravikiran G Thirumalai To: akpm@linux-foundation.org Cc: wli@movementarian.org, mel@csn.ul.ie, linux-mm@kvack.org, shai@scalex86.org, linux-kernel@vger.kernel.org Subject: [patch 1/2] mm: Fix SHM_HUGETLB to work with users in hugetlb_shm_group Message-ID: <20090221015457.GA32674@localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.15+20070412 (2007-04-11) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - byss.tchmachines.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - scalex86.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a two patch series to fix a long standing inconsistency with the mechanism to allow non root users allocate hugetlb shm. The patch changelog is self explanatory. Here's a link to the previous discussion as well: http://lkml.org/lkml/2009/2/10/89 --- Fix hugetlb subsystem so that non root users belonging to hugetlb_shm_group can actually allocate hugetlb backed shm. Currently non root users cannot even map one large page using SHM_HUGETLB when they belong to the gid in /proc/sys/vm/hugetlb_shm_group. This is because allocation size is verified against RLIMIT_MEMLOCK resource limit even if the user belongs to hugetlb_shm_group. This patch 1. Fixes hugetlb subsystem so that users with CAP_IPC_LOCK and users belonging to hugetlb_shm_group don't need to be restricted with RLIMIT_MEMLOCK resource limits 2. This patch also disables mlock based rlimit checking (which will be reinstated and marked deprecated in a subsequent patch). Signed-off-by: Ravikiran Thirumalai Cc: Mel Gorman Cc: Wli Index: linux-2.6-tip/fs/hugetlbfs/inode.c =================================================================== --- linux-2.6-tip.orig/fs/hugetlbfs/inode.c 2009-02-10 13:24:56.000000000 -0800 +++ linux-2.6-tip/fs/hugetlbfs/inode.c 2009-02-10 13:30:05.000000000 -0800 @@ -942,9 +942,7 @@ static struct vfsmount *hugetlbfs_vfsmou static int can_do_hugetlb_shm(void) { - return likely(capable(CAP_IPC_LOCK) || - in_group_p(sysctl_hugetlb_shm_group) || - can_do_mlock()); + return (capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group)); } struct file *hugetlb_file_setup(const char *name, size_t size) @@ -962,9 +960,6 @@ struct file *hugetlb_file_setup(const ch if (!can_do_hugetlb_shm()) return ERR_PTR(-EPERM); - if (!user_shm_lock(size, user)) - return ERR_PTR(-ENOMEM); - root = hugetlbfs_vfsmount->mnt_root; quick_string.name = name; quick_string.len = strlen(quick_string.name); @@ -1002,7 +997,6 @@ out_inode: out_dentry: dput(dentry); out_shm_unlock: - user_shm_unlock(size, user); return ERR_PTR(error); }