futex_proxy_trylock_atomic (9)

int futex_proxy_trylock_atomic(u32 __user * pifutex, struct futex_hash_bucket * hb1, struct futex_hash_bucket * hb2, union futex_key * key1, union futex_key * key2, struct futex_pi_state ** ps, int set_waiters);

pifutex

the user address of the to futex

hb1

the from futex hash bucket, must be locked by the caller

hb2

the to futex hash bucket, must be locked by the caller

key1

the from futex key

key2

the to futex key

ps

address to store the pi_state pointer

set_waiters

force setting the FUTEX_WAITERS bit (1) or not (0)

Try and get the lock on behalf of the top waiter if we can do it atomically. Wake the top waiter if we succeed. If the caller specified set_waiters, then direct futex_lock_pi_atomic to force setting the FUTEX_WAITERS bit. hb1 and hb2 must be held by the caller.

0 - failed to acquire the lock atomically; >0 - acquired the lock, return value is vpid of the top_waiter <0 - error

Rusty Russell <[email protected]>

Author.