[PATCH 08/16] mm: use vm_unmapped_area() in hugetlbfs

[Michel Lespinasse <walken@google.com>]

Update the hugetlb_get_unmapped_area function to make use of
vm_unmapped_area() instead of implementing a brute force search.

Signed-off-by: Michel Lespinasse <walken@google.com>

---
 fs/hugetlbfs/inode.c |   42 ++++++++----------------------------------
 1 files changed, 8 insertions(+), 34 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index c5bc355d8243..14bc0c1fb4fb 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -151,8 +151,8 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long 
addr,
 {
        struct mm_struct *mm = current->mm;
        struct vm_area_struct *vma;
-       unsigned long start_addr;
        struct hstate *h = hstate_file(file);
+       struct vm_unmapped_area_info info;
 
        if (len & ~huge_page_mask(h))
                return -EINVAL;
@@ -173,39 +173,13 @@ hugetlb_get_unmapped_area(struct file *file, unsigned 
long addr,
                        return addr;
        }
 
-       if (len > mm->cached_hole_size)
-               start_addr = mm->free_area_cache;
-       else {
-               start_addr = TASK_UNMAPPED_BASE;
-               mm->cached_hole_size = 0;
-       }
-
-full_search:
-       addr = ALIGN(start_addr, huge_page_size(h));
-
-       for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
-               /* At this point:  (!vma || addr < vma->vm_end). */
-               if (TASK_SIZE - len < addr) {
-                       /*
-                        * Start a new search - just in case we missed
-                        * some holes.
-                        */
-                       if (start_addr != TASK_UNMAPPED_BASE) {
-                               start_addr = TASK_UNMAPPED_BASE;
-                               mm->cached_hole_size = 0;
-                               goto full_search;
-                       }
-                       return -ENOMEM;
-               }
-
-               if (!vma || addr + len <= vma->vm_start) {
-                       mm->free_area_cache = addr + len;
-                       return addr;
-               }
-               if (addr + mm->cached_hole_size < vma->vm_start)
-                       mm->cached_hole_size = vma->vm_start - addr;
-               addr = ALIGN(vma->vm_end, huge_page_size(h));
-       }
+       info.flags = 0;
+       info.length = len;
+       info.low_limit = TASK_UNMAPPED_BASE;
+       info.high_limit = TASK_SIZE;
+       info.align_mask = PAGE_MASK & ~huge_page_mask(h);
+       info.align_offset = 0;
+       return vm_unmapped_area(&info);
 }
 #endif
 
-- 
1.7.7.3