struct page             **pages;
        unsigned int            nr_pages;
        phys_addr_t             phys_addr;
-       void                    *caller;
+       const void              *caller;
 };
 
 /*
 extern void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot);
 extern void *__vmalloc_node_range(unsigned long size, unsigned long align,
                        unsigned long start, unsigned long end, gfp_t gfp_mask,
-                       pgprot_t prot, int node, void *caller);
+                       pgprot_t prot, int node, const void *caller);
 extern void vfree(const void *addr);
 
 extern void *vmap(struct page **pages, unsigned int count,
 
 extern struct vm_struct *get_vm_area(unsigned long size, unsigned long flags);
 extern struct vm_struct *get_vm_area_caller(unsigned long size,
-                                       unsigned long flags, void *caller);
+                                       unsigned long flags, const void *caller);
 extern struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
                                        unsigned long start, unsigned long end);
 extern struct vm_struct *__get_vm_area_caller(unsigned long size,
                                        unsigned long flags,
                                        unsigned long start, unsigned long end,
-                                       void *caller);
+                                       const void *caller);
 extern struct vm_struct *remove_vm_area(const void *addr);
 
 extern int map_vm_area(struct vm_struct *area, pgprot_t prot,
 
 struct vm_struct *vmlist;
 
 static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
-                             unsigned long flags, void *caller)
+                             unsigned long flags, const void *caller)
 {
        vm->flags = flags;
        vm->addr = (void *)va->va_start;
 }
 
 static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
-                             unsigned long flags, void *caller)
+                             unsigned long flags, const void *caller)
 {
        setup_vmalloc_vm(vm, va, flags, caller);
        insert_vmalloc_vmlist(vm);
 
 static struct vm_struct *__get_vm_area_node(unsigned long size,
                unsigned long align, unsigned long flags, unsigned long start,
-               unsigned long end, int node, gfp_t gfp_mask, void *caller)
+               unsigned long end, int node, gfp_t gfp_mask, const void *caller)
 {
        struct vmap_area *va;
        struct vm_struct *area;
 
 struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
                                       unsigned long start, unsigned long end,
-                                      void *caller)
+                                      const void *caller)
 {
        return __get_vm_area_node(size, 1, flags, start, end, -1, GFP_KERNEL,
                                  caller);
 }
 
 struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
-                               void *caller)
+                               const void *caller)
 {
        return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
                                                -1, GFP_KERNEL, caller);
 
 static void *__vmalloc_node(unsigned long size, unsigned long align,
                            gfp_t gfp_mask, pgprot_t prot,
-                           int node, void *caller);
+                           int node, const void *caller);
 static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
-                                pgprot_t prot, int node, void *caller)
+                                pgprot_t prot, int node, const void *caller)
 {
        const int order = 0;
        struct page **pages;
  */
 void *__vmalloc_node_range(unsigned long size, unsigned long align,
                        unsigned long start, unsigned long end, gfp_t gfp_mask,
-                       pgprot_t prot, int node, void *caller)
+                       pgprot_t prot, int node, const void *caller)
 {
        struct vm_struct *area;
        void *addr;
  */
 static void *__vmalloc_node(unsigned long size, unsigned long align,
                            gfp_t gfp_mask, pgprot_t prot,
-                           int node, void *caller)
+                           int node, const void *caller)
 {
        return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
                                gfp_mask, prot, node, caller);