X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=mm%2Ffremap.c;h=14bd3bf7826edcecd2f61e6465b61078a84b2340;hb=b192541b39ed29ff82f9f2d5427f451e89617f1c;hp=5f50d736a03779dc12606abf99c46031ee45437a;hpb=d0217ac04ca6591841e5665f518e38064f4e65bd;p=linux-2.6-omap-h63xx.git

diff --git a/mm/fremap.c b/mm/fremap.c
index 5f50d736a03..14bd3bf7826 100644
--- 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:
@@ -160,7 +162,7 @@ asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
 	if (vma->vm_private_data && !(vma->vm_flags & VM_NONLINEAR))
 		goto out;
 
-	if (!vma->vm_flags & VM_CAN_NONLINEAR)
+	if (!(vma->vm_flags & VM_CAN_NONLINEAR))
 		goto out;
 
 	if (end <= start || start < vma->vm_start || end > vma->vm_end)
@@ -181,6 +183,25 @@ asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
 			goto retry;
 		}
 		mapping = vma->vm_file->f_mapping;
+		/*
+		 * page_mkclean doesn't work on nonlinear vmas, so if
+		 * dirty pages need to be accounted, emulate with linear
+		 * vmas.
+		 */
+		if (mapping_cap_account_dirty(mapping)) {
+			unsigned long addr;
+
+			flags &= MAP_NONBLOCK;
+			addr = mmap_region(vma->vm_file, start, size,
+					flags, vma->vm_flags, pgoff, 1);
+			if (IS_ERR_VALUE(addr)) {
+				err = addr;
+			} else {
+				BUG_ON(addr != start);
+				err = 0;
+			}
+			goto out;
+		}
 		spin_lock(&mapping->i_mmap_lock);
 		flush_dcache_mmap_lock(mapping);
 		vma->vm_flags |= VM_NONLINEAR;