Re: [PATCH] key: Add placeholder arg to Diffie-Hellman syscall

The final version of the syscall that went in to kernel 4.7 added a reserved arg to the KEYCTL_DH_COMPUTE syscall. In the future, this arg will be used to optionally specify a key derivation function. For now, it's needed so the system call doesn't return -1 (errno == EINVAL) every time.