Is it a lapsus calami in init_io_cache?

[Mr. Left]

Hi, all
I am reading the source code of mysql 5.6.6-m9, and i found the code below in
function:init_io_cache

/* Clear mutex so that safe_mutex will notice that it's not initialized */   
memset(&info->append_buffer_lock, 0, sizeof(info));

I want to know why use sizeof(info) instead of sizeof(info->append_buffer_lock) ?

Best Regards!