[PATCH -mm] Revoke core code: fix nommu arch compiling error bug

["Wu, Bryan" <bryan.wu@analog.com>]

Hi folks,

As struct mm_struct vm_mm is hidden in struct vm_area_struct in NOMMU
arch, this is a fixing method when compiling failure on blackfin arch.

Signed-off-by: Bryan Wu <bryan.wu@analog.com> 
---

 fs/revoke.c |   22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

Index: linux-2.6/fs/revoke.c
===================================================================
--- linux-2.6.orig/fs/revoke.c
+++ linux-2.6/fs/revoke.c
@@ -207,13 +207,21 @@
 /*
  *	LOCKING: spin_lock(&mapping->i_mmap_lock)
  */
-static int revoke_mm(struct mm_struct *mm, struct address_space *mapping,
+static int revoke_mm(struct vm_area_struct *vma, struct address_space *mapping,
 		     struct file *to_exclude)
 {
-	struct vm_area_struct *vma;
+#ifdef CONFIG_MMU
+	struct mm_struct *mm = vma->vm_mm;
+#else
+	struct mm_struct *mm = 0;
+#endif
+	struct vm_area_struct *_vma;
 	struct zap_details details;
 	int err = 0;
 
+	if (!mm)
+		return -ENOENT;
+
 	details.i_mmap_lock = &mapping->i_mmap_lock;
 
 	/*
@@ -224,11 +232,11 @@
 		err = -EAGAIN;
 		goto out;
 	}
-	for (vma = mm->mmap; vma != NULL; vma = vma->vm_next) {
-		if (!need_revoke(vma, to_exclude))
+	for (_vma = mm->mmap; _vma != NULL; _vma = _vma->vm_next) {
+		if (!need_revoke(_vma, to_exclude))
 			continue;
 
-		err = revoke_vma(vma, &details);
+		err = revoke_vma(_vma, &details);
 		if (err)
 			break;
 	}
@@ -254,7 +262,7 @@
 		if (likely(!need_revoke(vma, to_exclude)))
 			continue;
 
-		err = revoke_mm(vma->vm_mm, mapping, to_exclude);
+		err = revoke_mm(vma, mapping, to_exclude);
 		if (err == -EAGAIN) {
 			try_again = 1;
 			continue;
@@ -284,7 +292,7 @@
 		if (likely(!need_revoke(vma, to_exclude)))
 			continue;
 
-		err = revoke_mm(vma->vm_mm, mapping, to_exclude);
+		err = revoke_mm(vma, mapping, to_exclude);
 		if (err == -EAGAIN) {
 			try_again = 1;
 			continue;
_

Thanks,
-Bryan Wu