arch/m68k/mm/kmap.c: introduce missing kfree

Error handling code following a kmalloc should free the allocated data.

The semantic match that finds the problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r exists@
local idexpression x;
statement S;
expression E;
identifier f,l;
position p1,p2;
expression *ptr != NULL;
@@

(
if ((x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...)) == NULL) S
|
x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
..
if (x == NULL) S
)
<... when != x
     when != if (...) { <+...x...+> }
x->f = E
..>
(
 return \(0\|<+...x...+>\|ptr\);
|
 return@p2 ...;
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/m68k/mm/kmap.c

@@ -66,8 +66,10 @@ static struct vm_struct *get_io_area(unsigned long size)
 	for (p = &iolist; (tmp = *p) ; p = &tmp->next) {
 		if (size + addr < (unsigned long)tmp->addr)
 			break;
-		if (addr > KMAP_END-size)
+		if (addr > KMAP_END-size) {
+			kfree(area);
 			return NULL;
+		}
 		addr = tmp->size + (unsigned long)tmp->addr;
 	}
 	area->addr = (void *)addr;