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Subject[RESEND] [PATCH] hugetlbfs: Do not call user_shm_lock() for MAP_HUGETLB fix
Date
It seems I may have been having relay problems, I am resending this using
my personal account to make sure everyone that needs a copy gets one.

Andrew,

This patch seems to have slipped through the cracks during the discussion
on the MAP_HUGETLB flag, I am sorry for letting it slip. Please fold this
into the indicated patch in -mm.

--- Cut here ---

The patch
hugetlbfs-allow-the-creation-of-files-suitable-for-map_private-on-the-vfs-internal-mount.patch
alters can_do_hugetlb_shm() to check if a file is being created for shared
memory or mmap(). If this returns false, we then unconditionally call
user_shm_lock() triggering a warning. This block should never be entered
for MAP_HUGETLB. This patch partially reverts the problem and fixes the check.

This patch should be considered a fix to
hugetlbfs-allow-the-creation-of-files-suitable-for-map_private-on-the-vfs-internal-mount.patch.

From: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Eric B Munson <ebmunson@us.ibm.com>
---
fs/hugetlbfs/inode.c | 12 +++---------
1 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index e1a4ac4..0bf9d02 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -931,15 +931,9 @@ static struct file_system_type hugetlbfs_fs_type = {

static struct vfsmount *hugetlbfs_vfsmount;

-static int can_do_hugetlb_shm(int creat_flags)
+static int can_do_hugetlb_shm(void)
{
- if (creat_flags != HUGETLBFS_SHMFS_INODE)
- return 0;
- if (capable(CAP_IPC_LOCK))
- return 1;
- if (in_group_p(sysctl_hugetlb_shm_group))
- return 1;
- return 0;
+ return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
}

struct file *hugetlb_file_setup(const char *name, size_t size, int acctflag,
@@ -955,7 +949,7 @@ 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(creat_flags)) {
+ if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
*user = current_user();
if (user_shm_lock(size, *user)) {
WARN_ONCE(1,
--
1.6.3.2


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