Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

[sfrench/cifs-2.6.git] / mm / fremap.c

diff --git a/mm/fremap.c b/mm/fremap.c
index 95bcb5641c722b6f4d7eb49801320e0a266f7c83..07a9c82ce1a3fa0e24da2f2da23e9416e3f1819c 100644 (file)
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -5,7 +5,7 @@
  *
  * started by Ingo Molnar, Copyright (C) 2002, 2003
  */
-
+#include <linux/backing-dev.h>
 #include <linux/mm.h>
 #include <linux/swap.h>
 #include <linux/file.h>
@@ -97,26 +97,28 @@ static int populate_range(struct mm_struct *mm, struct vm_area_struct *vma,
 
 }
 
-/***
- * sys_remap_file_pages - remap arbitrary pages of a shared backing store
- *                        file within an existing vma.
+/**
+ * sys_remap_file_pages - remap arbitrary pages of an existing VM_SHARED vma
  * @start: start of the remapped virtual memory range
  * @size: size of the remapped virtual memory range
- * @prot: new protection bits of the range
- * @pgoff: to be mapped page of the backing store file
+ * @prot: new protection bits of the range (see NOTE)
+ * @pgoff: to-be-mapped page of the backing store file
  * @flags: 0 or MAP_NONBLOCKED - the later will cause no IO.
  *
- * this syscall works purely via pagetables, so it's the most efficient
+ * sys_remap_file_pages remaps arbitrary pages of an existing VM_SHARED vma
+ * (shared backing store file).
+ *
+ * This syscall works purely via pagetables, so it's the most efficient
  * way to map the same (large) file into a given virtual window. Unlike
  * mmap()/mremap() it does not create any new vmas. The new mappings are
  * also safe across swapout.
  *
- * NOTE: the 'prot' parameter right now is ignored, and the vma's default
- * protection is used. Arbitrary protections might be implemented in the
- * future.
+ * NOTE: the @prot parameter right now is ignored (but must be zero),
+ * and the vma's default protection is used. Arbitrary protections
+ * might be implemented in the future.
  */
 asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
-       unsigned long __prot, unsigned long pgoff, unsigned long flags)
+       unsigned long prot, unsigned long pgoff, unsigned long flags)
 {
        struct mm_struct *mm = current->mm;
        struct address_space *mapping;
@@ -125,7 +127,7 @@ asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
        int err = -EINVAL;
        int has_write_lock = 0;
 
-       if (__prot)
+       if (prot)
                return err;
        /*
         * Sanitize the syscall parameters:
@@ -188,10 +190,13 @@ asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
                 */
                if (mapping_cap_account_dirty(mapping)) {
                        unsigned long addr;
+                       struct file *file = vma->vm_file;
 
                        flags &= MAP_NONBLOCK;
-                       addr = mmap_region(vma->vm_file, start, size,
+                       get_file(file);
+                       addr = mmap_region(file, start, size,
                                        flags, vma->vm_flags, pgoff, 1);
+                       fput(file);
                        if (IS_ERR_VALUE(addr)) {
                                err = addr;
                        } else {