rwlock different behavior on glibc 2.28 then on previous versions

[Florian Weimer]

* David Mozes:

> On the previous version of Glibc (before the commit) We could release
> write lock with different thread as the one that owned the lock (If we
> like) .

Sorry, this misuse of the API has always been undefined according to
POSIX (“Results are undefined if the read-write lock rwlock is not held
by the calling thread.”).

> This is help very much for async program that has a many threads that
> communicate with some target.  And we like to define a call back
> function instead of blocking on aio thread that send the data in order
> to release the rwlock.this improves the performance dramatically .

Could you use a different synchronization object (perhaps a condition
variable)?

Thanks,
Florian