Function k_spin_lock

pub unsafe extern "C" fn k_spin_lock(
    l: *mut k_spinlock,
) -> z_spinlock_key

@brief Lock a spinlock

This routine locks the specified spinlock, returning a key handle representing interrupt state needed at unlock time. Upon returning, the calling thread is guaranteed not to be suspended or interrupted on its current CPU until it calls k_spin_unlock(). The implementation guarantees mutual exclusion: exactly one thread on one CPU will return from k_spin_lock() at a time. Other CPUs trying to acquire a lock already held by another CPU will enter an implementation-defined busy loop (“spinning”) until the lock is released.

Separate spin locks may be nested. It is legal to lock an (unlocked) spin lock while holding a different lock. Spin locks are not recursive, however: an attempt to acquire a spin lock that the CPU already holds will deadlock.

In circumstances where only one CPU exists, the behavior of k_spin_lock() remains as specified above, though obviously no spinning will take place. Implementations may be free to optimize in uniprocessor contexts such that the locking reduces to an interrupt mask operation.

@param l A pointer to the spinlock to lock @return A key value that must be passed to k_spin_unlock() when the lock is released.