@@ -130,6 +130,53 @@ static void subpage_prot_clear(unsigned long addr, unsigned long len)
up_write(&mm->mmap_sem);
}
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static int subpage_walk_pmd_entry(pmd_t *pmd, unsigned long addr,
+ unsigned long end, struct mm_walk *walk)
+{
+ struct vm_area_struct *vma = walk->private;
+ split_huge_page_pmd(vma, addr, pmd);
+ return 0;
+}
+
+static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
+ unsigned long len)
+{
+ struct vm_area_struct *vma;
+ struct mm_walk subpage_proto_walk = {
+ .mm = mm,
+ .pmd_entry = subpage_walk_pmd_entry,
+ };
+
+ /*
+ * We don't try too hard, we just mark all the vma in that range
+ * VM_NOHUGEPAGE and split them.
+ */
+ vma = find_vma(mm, addr);
+ /*
+ * If the range is in unmapped range, just return
+ */
+ if (vma && ((addr + len) <= vma->vm_start))
+ return;
+
+ while (vma) {
+ if (vma->vm_start >= (addr + len))
+ break;
+ vma->vm_flags |= VM_NOHUGEPAGE;
+ subpage_proto_walk.private = vma;
+ walk_page_range(vma->vm_start, vma->vm_end,
+ &subpage_proto_walk);
+ vma = vma->vm_next;
+ }
+}
+#else
+static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
+ unsigned long len)
+{
+ return;
+}
+#endif
+
/*
* Copy in a subpage protection map for an address range.
* The map has 2 bits per 4k subpage, so 32 bits per 64k page.
@@ -168,6 +215,7 @@ long sys_subpage_prot(unsigned long addr, unsigned long len, u32 __user *map)
return -EFAULT;
down_write(&mm->mmap_sem);
+ subpage_mark_vma_nohuge(mm, addr, len);
for (limit = addr + len; addr < limit; addr = next) {
next = pmd_addr_end(addr, limit);
err = -ENOMEM;