bpf: Use bpf_map_area_free instread of kvfree

bpf_map_area_alloc() should be paired with bpf_map_area_free().
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20220810151840.16394-3-laoar.shao@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

kernel/bpf/ringbuf.c

@@ -116,7 +116,7 @@ static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node)
 err_free_pages:
 	for (i = 0; i < nr_pages; i++)
 		__free_page(pages[i]);
-	kvfree(pages);
+	bpf_map_area_free(pages);
 	return NULL;
 }
 
@@ -190,7 +190,7 @@ static void bpf_ringbuf_free(struct bpf_ringbuf *rb)
 	vunmap(rb);
 	for (i = 0; i < nr_pages; i++)
 		__free_page(pages[i]);
-	kvfree(pages);
+	bpf_map_area_free(pages);
 }
 
 static void ringbuf_map_free(struct bpf_map *map)