mm: reintroduce and deprecate rlimit based access for SHM_HUGETLB

---------------------------

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 <kiran@scalex86.org>

---------------------------

What:	CONFIG_THERMAL_HWMON

When:	January 2009

Why:	This option was introduced just to allow older lm-sensors userspace

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;

	if (!hugetlbfs_vfsmount)

		return ERR_PTR(-ENOENT);

	if (!can_do_hugetlb_shm())

	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;

out_dentry:

	dput(dentry);

out_shm_unlock:

	if (unlock_shm)

		user_shm_unlock(size, user);

	return ERR_PTR(error);

}