mm/mmap.c: use while instead of if+goto

The creators of the C language gave us the while keyword. Let's use
that instead of synthesizing it from if+goto.

Made possible by 6597d783 ("mm/mmap.c: replace find_vma_prepare()
with clearer find_vma_links()").

[akpm@linux-foundation.org: fix 80-col overflows]
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mmap.c

@@ -1551,11 +1551,10 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 
 	/* Clear old maps */
 	error = -ENOMEM;
-munmap_back:
-	if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) {
+	while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
+			      &rb_parent)) {
 		if (do_munmap(mm, addr, len))
 			return -ENOMEM;
-		goto munmap_back;
 	}
 
 	/*
@@ -1571,7 +1570,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	/*
 	 * Can we just expand an old mapping?
 	 */
-	vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
+	vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff,
+			NULL);
 	if (vma)
 		goto out;
 
@@ -2739,11 +2739,10 @@ static unsigned long do_brk(unsigned long addr, unsigned long len)
 	/*
 	 * Clear old maps.  this also does some error checking for us
 	 */
- munmap_back:
-	if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) {
+	while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
+			      &rb_parent)) {
 		if (do_munmap(mm, addr, len))
 			return -ENOMEM;
-		goto munmap_back;
 	}
 
 	/* Check against address space limits *after* clearing old maps... */