not spinlock_t. Spinlock_t and the associated functions and macros may
require blocking signals in order for async-safe libc functions to behave
appropriately in libthr. This is undesriable for libthr internal locking.
So, this is the first step in completely separating libthr from libc's
locking primitives.
Three new macros should be used for internal libthr locking from now on:
THR_LOCK, THR_TRYLOCK, THR_UNLOCK.
exit function has invalidated the need for _spin[un]lock_pthread().
The _spin[un]lock() functions can now dereference curthread without
the danger that the ldtentry containing the pointer to the thread
has been cleared out from under them.
joined and then the joiner thread. There isn't an easy (sane?) way
to make it use the correct order without introducing races involving
the target thread and finding which (active or dead) list it is on. So,
after locking the canceled thread it will try to lock the joined thread
and if it fails release the first lock and try again from the top.
Introduce a new function, _spintrylock, which is simply a wrapper arround
umtx_trylock(), to help accomplish this.
Approved by: re/blanket libthr
that take the address of a struct pthread as their first argument.
_spin[un]lock() just become wrappers arround these two functions.
These new functions are for use in situations where curthread can't be
used. One example is _thread_retire(), where we invalidate the array index
curthread uses to get its pointer..
Approved by: re/blanket libthr
_get_curthread(). This is similar to the kernel's curthread. Doing
this saves stack overhead and is more convenient to the programmer.
- Pass the pointer to the newly created thread to _thread_init().
- Remove _get_curthread_slow().
