lib/lru_cache: fix error free handing in lc_create

When kmem_cache_alloc in function lc_create returns null, we will
free the memory already allocated. The loop of kmem_cache_free
is wrong, especially:
  i = 0  ==> do wrong loop
  i > 0  ==> do not free element[0]

Link: https://lkml.kernel.org/r/20220618082521.7082-1-wuchi.zero@gmail.com
Signed-off-by: wuchi <wuchi.zero@gmail.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Christoph Bhmwalder <christoph.boehmwalder@linbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/lru_cache.c

@@ -147,8 +147,8 @@ struct lru_cache *lc_create(const char *name, struct kmem_cache *cache,
 		return lc;
 
 	/* else: could not allocate all elements, give up */
-	for (i--; i; i--) {
-		void *p = element[i];
+	while (i) {
+		void *p = element[--i];
 		kmem_cache_free(cache, p - e_off);
 	}
 	kfree(lc);