const: mark struct vm_struct_operations

* mark struct vm_area_struct::vm_ops as const
* mark vm_ops in AGP code

But leave TTM code alone, something is fishy there with global vm_ops
being used.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/agp_backend.h b/include/linux/agp_backend.h
index 880130f..9101ed64 100644
--- a/include/linux/agp_backend.h
+++ b/include/linux/agp_backend.h
@@ -53,7 +53,7 @@
 	int current_memory;
 	bool cant_use_aperture;
 	unsigned long page_mask;
-	struct vm_operations_struct *vm_ops;
+	const struct vm_operations_struct *vm_ops;
 };
 
 /*
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 1693799..41a59af 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -163,7 +163,7 @@
 }
 
 extern const struct file_operations hugetlbfs_file_operations;
-extern struct vm_operations_struct hugetlb_vm_ops;
+extern const struct vm_operations_struct hugetlb_vm_ops;
 struct file *hugetlb_file_setup(const char *name, size_t size, int acct,
 				struct user_struct **user, int creat_flags);
 int hugetlb_get_quota(struct address_space *mapping, long delta);
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 21d6aa4..84a524a 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -171,7 +171,7 @@
 	struct anon_vma *anon_vma;	/* Serialized by page_table_lock */
 
 	/* Function pointers to deal with this struct. */
-	struct vm_operations_struct * vm_ops;
+	const struct vm_operations_struct *vm_ops;
 
 	/* Information about our backing store: */
 	unsigned long vm_pgoff;		/* Offset (within vm_file) in PAGE_SIZE
diff --git a/include/linux/ramfs.h b/include/linux/ramfs.h
index 37aaf2b..4e768dd 100644
--- a/include/linux/ramfs.h
+++ b/include/linux/ramfs.h
@@ -17,7 +17,7 @@
 #endif
 
 extern const struct file_operations ramfs_file_operations;
-extern struct vm_operations_struct generic_file_vm_ops;
+extern const struct vm_operations_struct generic_file_vm_ops;
 extern int __init init_rootfs(void);
 
 #endif