[PATCH] shmem_getpage_locked missing unlock

Dawson Engler's Stanford Checker reported this missing unlock to
LKML 11 July (amongst "56 potential lock/unlock bugs in 2.5.8").

mm/shmem.c

@@ -605,6 +605,7 @@ static struct page * shmem_getpage_locked(struct shmem_inode_info *info, struct
 		}
 		error = move_from_swap_cache(page, idx, mapping);
 		if (error < 0) {
+			spin_unlock(&info->lock);
 			unlock_page(page);
 			page_cache_release(page);
 			return ERR_PTR(error);