FUTEX_WAIT_SETUP(9)                    Futex API reference                    FUTEX_WAIT_SETUP(9)



NAME
       futex_wait_setup - Prepare to wait on a futex

SYNOPSIS
       int futex_wait_setup(u32 __user * uaddr, u32 val, unsigned int flags, struct futex_q * q,
                            struct futex_hash_bucket ** hb);

ARGUMENTS
       uaddr
           the futex userspace address

       val
           the expected value

       flags
           futex flags (FLAGS_SHARED, etc.)

       q
           the associated futex_q

       hb
           storage for hash_bucket pointer to be returned to caller

DESCRIPTION
       Setup the futex_q and locate the hash_bucket. Get the futex value and compare it with the
       expected value. Handle atomic faults internally. Return with the hb lock held and a q.key
       reference on success, and unlocked with no q.key reference on failure.

RETURN
       0 - uaddr contains val and hb has been locked; <1 - -EFAULT or -EWOULDBLOCK (uaddr does
       not contain val) and hb is unlocked

AUTHOR
       Rusty Russell <rusty AT rustcorp.au>
           Author.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                       FUTEX_WAIT_SETUP(9)