MPTCTL_SYSCALL_DOWN(9) Message-based devices MPTCTL_SYSCALL_DOWN(9)NAMEmptctl_syscall_down - Down the MPT adapter syscall semaphore.SYNOPSISint mptctl_syscall_down(MPT_ADAPTER * ioc, int nonblock);ARGUMENTSioc Pointer to MPT adapter nonblock boolean, non-zero if O_NONBLOCK is setDESCRIPTIONAll of the ioctl commands can potentially sleep, which is illegal with a spinlock held, thus we perform mutual exclusion here. Returns negative errno on error, or zero for success.COPYRIGHTKernel Hackers Manual 3.10 June 2014 MPTCTL_SYSCALL_DOWN(9)