ath9k/htc_drv_main: off by one error

[safe/jmp/linux-2.6] / mm / mremap.c

diff --git a/mm/mremap.c b/mm/mremap.c
index 5f34617..8451908 100644 (file)
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -321,6 +321,7 @@ static unsigned long mremap_to(unsigned long addr,
        struct vm_area_struct *vma;
        unsigned long ret = -EINVAL;
        unsigned long charged = 0;
+       unsigned long map_flags;
 
        if (new_addr & ~PAGE_MASK)
                goto out;
@@ -358,14 +359,39 @@ static unsigned long mremap_to(unsigned long addr,
                goto out;
        }
 
-       ret = move_vma(vma, addr, old_len, new_len, new_addr);
+       map_flags = MAP_FIXED;
+       if (vma->vm_flags & VM_MAYSHARE)
+               map_flags |= MAP_SHARED;
+
+       ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff +
+                               ((addr - vma->vm_start) >> PAGE_SHIFT),
+                               map_flags);
        if (ret & ~PAGE_MASK)
-               vm_unacct_memory(charged);
+               goto out1;
+
+       ret = move_vma(vma, addr, old_len, new_len, new_addr);
+       if (!(ret & ~PAGE_MASK))
+               goto out;
+out1:
+       vm_unacct_memory(charged);
 
 out:
        return ret;
 }
 
+static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
+{
+       unsigned long end = vma->vm_end + delta;
+       if (end < vma->vm_end) /* overflow */
+               return 0;
+       if (vma->vm_next && vma->vm_next->vm_start < end) /* intersection */
+               return 0;
+       if (get_unmapped_area(NULL, vma->vm_start, end - vma->vm_start,
+                             0, MAP_FIXED) & ~PAGE_MASK)
+               return 0;
+       return 1;
+}
+
 /*
  * Expand (or shrink) an existing mapping, potentially moving it at the
  * same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
@@ -430,11 +456,8 @@ unsigned long do_mremap(unsigned long addr,
        /* old_len exactly to the end of the area..
         */
        if (old_len == vma->vm_end - addr) {
-               unsigned long max_addr = TASK_SIZE;
-               if (vma->vm_next)
-                       max_addr = vma->vm_next->vm_start;
                /* can we just expand the current mapping? */
-               if (max_addr - addr >= new_len) {
+               if (vma_expandable(vma, new_len - old_len)) {
                        int pages = (new_len - old_len) >> PAGE_SHIFT;
 
                        vma_adjust(vma, vma->vm_start,
@@ -463,7 +486,9 @@ unsigned long do_mremap(unsigned long addr,
                        map_flags |= MAP_SHARED;
 
                new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
-                                       vma->vm_pgoff, map_flags);
+                                       vma->vm_pgoff +
+                                       ((addr - vma->vm_start) >> PAGE_SHIFT),
+                                       map_flags);
                if (new_addr & ~PAGE_MASK) {
                        ret = new_addr;
                        goto out;