diff --git a/include/asm-ia64/pgtable.h b/include/asm-ia64/pgtable.h
index e6204f14f6142222cc3b7b06d469ffbf5a1d4a6e..ed70862ea2473ee8e2d2a79a975293a97b2fb550 100644
--- a/include/asm-ia64/pgtable.h
+++ b/include/asm-ia64/pgtable.h
@@ -371,7 +371,7 @@ pgd_index (unsigned long address)
 /* The offset in the 1-level directory is given by the 3 region bits
    (61..63) and the level-1 bits.  */
 static inline pgd_t*
-pgd_offset (struct mm_struct *mm, unsigned long address)
+pgd_offset (const struct mm_struct *mm, unsigned long address)
 {
 	return mm->pgd + pgd_index(address);
 }