futex_wait_setup (9)

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

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

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.

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

Rusty Russell <[email protected]>

Author.