mm: memcontrol: remove dead code from memory_max_write()

When the reclaim loop in memory_max_write() is ^C'd or similar, we set err
to -EINTR.  But we don't return err.  Once the limit is set, we always
return success (nbytes).  Delete the dead code.

Link: http://lkml.kernel.org/r/20191022201518.341216-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memcontrol.c

@@ -6139,10 +6139,8 @@ static ssize_t memory_max_write(struct kernfs_open_file *of,
 		if (nr_pages <= max)
 			break;
 
-		if (signal_pending(current)) {
-			err = -EINTR;
+		if (signal_pending(current))
 			break;
-		}
 
 		if (!drained) {
 			drain_all_stock(memcg);