mm: vm_unmapped_area() lookup function

[linux-block.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index bcaab4e6fe913ac6e3f2ef0a6c83ea24d8972867..4af4f0b1be4cad5cf231d565f5116745aa969a35 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1456,6 +1456,37 @@ extern unsigned long vm_mmap(struct file *, unsigned long,
         unsigned long, unsigned long,
         unsigned long, unsigned long);
 
+struct vm_unmapped_area_info {
+#define VM_UNMAPPED_AREA_TOPDOWN 1
+       unsigned long flags;
+       unsigned long length;
+       unsigned long low_limit;
+       unsigned long high_limit;
+       unsigned long align_mask;
+       unsigned long align_offset;
+};
+
+extern unsigned long unmapped_area(struct vm_unmapped_area_info *info);
+extern unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info);
+
+/*
+ * Search for an unmapped address range.
+ *
+ * We are looking for a range that:
+ * - does not intersect with any VMA;
+ * - is contained within the [low_limit, high_limit) interval;
+ * - is at least the desired size.
+ * - satisfies (begin_addr & align_mask) == (align_offset & align_mask)
+ */
+static inline unsigned long
+vm_unmapped_area(struct vm_unmapped_area_info *info)
+{
+       if (!(info->flags & VM_UNMAPPED_AREA_TOPDOWN))
+               return unmapped_area(info);
+       else
+               return unmapped_area_topdown(info);
+}
+
 /* truncate.c */
 extern void truncate_inode_pages(struct address_space *, loff_t);
 extern void truncate_inode_pages_range(struct address_space *,