mm: nommu: find vma using the sorted vma list

Now we have the sorted vma list, use it in the find_vma[_exact]() rather
than doing linear search on the rb-tree.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/nommu.c

@@ -804,17 +804,15 @@ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
 {
 	struct vm_area_struct *vma;
-	struct rb_node *n = mm->mm_rb.rb_node;
 
 	/* check the cache first */
 	vma = mm->mmap_cache;
 	if (vma && vma->vm_start <= addr && vma->vm_end > addr)
 		return vma;
 
-	/* trawl the tree (there may be multiple mappings in which addr
+	/* trawl the list (there may be multiple mappings in which addr
 	 * resides) */
-	for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
-		vma = rb_entry(n, struct vm_area_struct, vm_rb);
+	for (vma = mm->mmap; vma; vma = vma->vm_next) {
 		if (vma->vm_start > addr)
 			return NULL;
 		if (vma->vm_end > addr) {
@@ -854,7 +852,6 @@ static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
 					     unsigned long len)
 {
 	struct vm_area_struct *vma;
-	struct rb_node *n = mm->mm_rb.rb_node;
 	unsigned long end = addr + len;
 
 	/* check the cache first */
@@ -862,10 +859,9 @@ static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
 	if (vma && vma->vm_start == addr && vma->vm_end == end)
 		return vma;
 
-	/* trawl the tree (there may be multiple mappings in which addr
+	/* trawl the list (there may be multiple mappings in which addr
 	 * resides) */
-	for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
-		vma = rb_entry(n, struct vm_area_struct, vm_rb);
+	for (vma = mm->mmap; vma; vma = vma->vm_next) {
 		if (vma->vm_start < addr)
 			continue;
 		if (vma->vm_start > addr)