futex_wait_setup9
Prepare to wait on a futex
Usage
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
Overview
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
Releases
2 releases since Debian 8 (Jessie); the text changed 1 time.