mm/vmalloc.c: fix memory ordering bug

[cascardo/linux.git] / mm / filemap_xip.c

diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index d8d9fe3..0d105ae 100644 (file)
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -155,22 +155,14 @@ xip_file_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
 EXPORT_SYMBOL_GPL(xip_file_read);
 
 /*
- * __xip_unmap is invoked from xip_unmap and
- * xip_write
+ * __xip_unmap is invoked from xip_unmap and xip_write
  *
  * This function walks all vmas of the address_space and unmaps the
  * __xip_sparse_page when found at pgoff.
  */
-static void
-__xip_unmap (struct address_space * mapping,
-                    unsigned long pgoff)
+static void __xip_unmap(struct address_space * mapping, unsigned long pgoff)
 {
        struct vm_area_struct *vma;
-       struct mm_struct *mm;
-       unsigned long address;
-       pte_t *pte;
-       pte_t pteval;
-       spinlock_t *ptl;
        struct page *page;
        unsigned count;
        int locked = 0;
@@ -182,11 +174,14 @@ __xip_unmap (struct address_space * mapping,
                return;
 
 retry:
-       mutex_lock(&mapping->i_mmap_mutex);
+       i_mmap_lock_read(mapping);
        vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
-               mm = vma->vm_mm;
-               address = vma->vm_start +
+               pte_t *pte, pteval;
+               spinlock_t *ptl;
+               struct mm_struct *mm = vma->vm_mm;
+               unsigned long address = vma->vm_start +
                        ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+
                BUG_ON(address < vma->vm_start || address >= vma->vm_end);
                pte = page_check_address(page, mm, address, &ptl, 1);
                if (pte) {
@@ -202,7 +197,7 @@ retry:
                        page_cache_release(page);
                }
        }
-       mutex_unlock(&mapping->i_mmap_mutex);
+       i_mmap_unlock_read(mapping);
 
        if (locked) {
                mutex_unlock(&xip_sparse_mutex);