mmap: remove the IA64-specific vma expansion implementation

With commit cf8e8658 ("arch: Remove Itanium (IA-64) architecture"),
there is no need to keep the IA64-specific vma expansion.

Clean up the IA64-specific vma expansion implementation.

Link: https://lkml.kernel.org/r/20231113124728.3974-1-lukas.bulwahn@gmail.comSigned-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/mmap.c

@@ -2207,42 +2207,7 @@ struct vm_area_struct *find_extend_vma_locked(struct mm_struct *mm, unsigned lon
 }
 #endif
 
-/*
- * IA64 has some horrid mapping rules: it can expand both up and down,
- * but with various special rules.
- *
- * We'll get rid of this architecture eventually, so the ugliness is
- * temporary.
- */
-#ifdef CONFIG_IA64
-static inline bool vma_expand_ok(struct vm_area_struct *vma, unsigned long addr)
-{
-	return REGION_NUMBER(addr) == REGION_NUMBER(vma->vm_start) &&
-		REGION_OFFSET(addr) < RGN_MAP_LIMIT;
-}
-
-/*
- * IA64 stacks grow down, but there's a special register backing store
- * that can grow up. Only sequentially, though, so the new address must
- * match vm_end.
- */
-static inline int vma_expand_up(struct vm_area_struct *vma, unsigned long addr)
-{
-	if (!vma_expand_ok(vma, addr))
-		return -EFAULT;
-	if (vma->vm_end != (addr & PAGE_MASK))
-		return -EFAULT;
-	return expand_upwards(vma, addr);
-}
-
-static inline bool vma_expand_down(struct vm_area_struct *vma, unsigned long addr)
-{
-	if (!vma_expand_ok(vma, addr))
-		return -EFAULT;
-	return expand_downwards(vma, addr);
-}
-
-#elif defined(CONFIG_STACK_GROWSUP)
+#if defined(CONFIG_STACK_GROWSUP)
 
 #define vma_expand_up(vma,addr) expand_upwards(vma, addr)
 #define vma_expand_down(vma, addr) (-EFAULT)