shm: fix the filename of hugetlb sysv shared memory

Some user space tools need to identify SYSV shared memory when examining
/proc/<pid>/maps.  To do so they look for a block device with major zero, a
dentry named SYSV<sysv key>, and having the minor of the internal sysv
shared memory kernel mount.

To help these tools and to make it easier for people just browsing
/proc/<pid>/maps this patch modifies hugetlb sysv shared memory to use the
SYSV<key> dentry naming convention.

User space tools will still have to be aware that hugetlb sysv shared
memory lives on a different internal kernel mount and so has a different
block device minor number from the rest of sysv shared memory.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Albert Cahalan <acahalan@gmail.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 5 deletions

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index aa083dd34e92..e6b46b3ac2fe 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -736,15 +736,13 @@ static int can_do_hugetlb_shm(void)
                         can_do_mlock());
 }
 
-struct file *hugetlb_zero_setup(size_t size)
+struct file *hugetlb_file_setup(const char *name, size_t size)
 {
         int error = -ENOMEM;
         struct file *file;
         struct inode *inode;
         struct dentry *dentry, *root;
         struct qstr quick_string;
-        char buf[16];
-        static atomic_t counter;
 
         if (!hugetlbfs_vfsmount)
                 return ERR_PTR(-ENOENT);
@@ -756,8 +754,7 @@ struct file *hugetlb_zero_setup(size_t size)
                 return ERR_PTR(-ENOMEM);
 
         root = hugetlbfs_vfsmount->mnt_root;
-        snprintf(buf, 16, "%u", atomic_inc_return(&counter));
-        quick_string.name = buf;
+        quick_string.name = name;
         quick_string.len = strlen(quick_string.name);
         quick_string.hash = 0;
         dentry = d_alloc(root, &quick_string);