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authorRavikiran G Thirumalai <kiran@scalex86.org>2009-03-31 15:21:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-01 08:59:12 -0700
commit2584e517320bd48dc8d20e38a2621a2dbe58fade (patch)
tree3b94b6c4cc10ab16ab106464e8d32e2e77ad8634
parent8a0bdec194c21c8fdef840989d0d7b742bb5d4bc (diff)
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 <kiran@scalex86.org> Reviewed-by: Mel Gorman <mel@csn.ul.ie> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Adam Litke <agl@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--Documentation/feature-removal-schedule.txt12
-rw-r--r--fs/hugetlbfs/inode.c13
2 files changed, 23 insertions, 2 deletions
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 5e02b83ac12..ea7d1bdad34 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -311,6 +311,18 @@ Who: Vlad Yasevich <vladislav.yasevich@hp.com>
---------------------------
+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
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index bc56df8ce00..23a3c76711e 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);
}