hugetlb: expose hugetlbfs_inode_info in header

hugetlbfs inode information will need to be accessed by code in
mm/shmem.c for file sealing operations.  Move inode information
definition from .c file to header for needed access.

Link: http://lkml.kernel.org/r/20171107122800.25517-4-marcandre.lureau@redhat.comSigned-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/hugetlbfs/inode.c

@@ -55,16 +55,6 @@ struct hugetlbfs_config {
 	umode_t			mode;
 };
 
-struct hugetlbfs_inode_info {
-	struct shared_policy policy;
-	struct inode vfs_inode;
-};
-
-static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
-{
-	return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
-}
-
 int sysctl_hugetlb_shm_group;
 
 enum {

include/linux/hugetlb.h

@@ -270,6 +270,16 @@ static inline struct hugetlbfs_sb_info *HUGETLBFS_SB(struct super_block *sb)
 	return sb->s_fs_info;
 }
 
+struct hugetlbfs_inode_info {
+	struct shared_policy policy;
+	struct inode vfs_inode;
+};
+
+static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
+{
+	return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
+}
+
 extern const struct file_operations hugetlbfs_file_operations;
 extern const struct vm_operations_struct hugetlb_vm_ops;
 struct file *hugetlb_file_setup(const char *name, size_t size, vm_flags_t acct,