HelenOS sources

futex_down         72 uspace/lib/c/generic/io/kio.c 	futex_down(&kio_buffer.futex);
futex_down         88 uspace/lib/c/generic/private/futex.h #define futex_lock(fut)     (void) futex_down((fut))
futex_down         94 uspace/lib/c/generic/thread/futex.c 	futex_down(futex);