From 2584e517320bd48dc8d20e38a2621a2dbe58fade Mon Sep 17 00:00:00 2001 From: Ravikiran G Thirumalai Date: Tue, 31 Mar 2009 15:21:26 -0700 Subject: [PATCH] mm: reintroduce and deprecate rlimit based access for SHM_HUGETLB Allow non root users with sufficient mlock rlimits to be able to allocate hugetlb backed shm for now. Deprecate this though. This is being deprecated because the mlock based rlimit checks for SHM_HUGETLB is not consistent with mmap based huge page allocations. Signed-off-by: Ravikiran Thirumalai Reviewed-by: Mel Gorman Cc: William Lee Irwin III Cc: Adam Litke Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/feature-removal-schedule.txt | 12 ++++++++++++ fs/hugetlbfs/inode.c | 13 +++++++++++-- 2 files changed, 23 insertions(+), 2 deletions(-) diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 5e02b83ac12b..ea7d1bdad34d 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -311,6 +311,18 @@ Who: Vlad Yasevich --------------------------- +What: Ability for non root users to shm_get hugetlb pages based on mlock + resource limits +When: 2.6.31 +Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or + have CAP_IPC_LOCK to be able to allocate shm segments backed by + huge pages. The mlock based rlimit check to allow shm hugetlb is + inconsistent with mmap based allocations. Hence it is being + deprecated. +Who: Ravikiran Thirumalai + +--------------------------- + What: CONFIG_THERMAL_HWMON When: January 2009 Why: This option was introduced just to allow older lm-sensors userspace diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index bc56df8ce001..23a3c76711e0 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -949,6 +949,7 @@ static int can_do_hugetlb_shm(void) struct file *hugetlb_file_setup(const char *name, size_t size, int acctflag) { int error = -ENOMEM; + int unlock_shm = 0; struct file *file; struct inode *inode; struct dentry *dentry, *root; @@ -958,8 +959,14 @@ struct file *hugetlb_file_setup(const char *name, size_t size, int acctflag) if (!hugetlbfs_vfsmount) return ERR_PTR(-ENOENT); - if (!can_do_hugetlb_shm()) - return ERR_PTR(-EPERM); + if (!can_do_hugetlb_shm()) { + if (user_shm_lock(size, user)) { + unlock_shm = 1; + WARN_ONCE(1, + "Using mlock ulimits for SHM_HUGETLB deprecated\n"); + } else + return ERR_PTR(-EPERM); + } root = hugetlbfs_vfsmount->mnt_root; quick_string.name = name; @@ -999,6 +1006,8 @@ out_inode: out_dentry: dput(dentry); out_shm_unlock: + if (unlock_shm) + user_shm_unlock(size, user); return ERR_PTR(error); } -- 2.20.1