The get_unused_fd() macro was removed upstream by https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f938612dd97d481b8b5bf960c992ae577f081c17 Thus replace get_unused_fd() by get_unused_fd_flags(0) which used to be the definition of the get_unused_fd() macro before it was removed. This fixes cryptodev compilation on kernel 4.0. Signed-off-by: Daniel Golle <daniel@makrotopia.org>