Simple spinlock operations

Declare/initialize with:

#include <linux/spinlock.h>

spinlock_t my_lock = SPIN_LOCK_UNLOCKED;
/* ... or (preferred) ... */
spinlock_t my_lock;
spin_lock_init(&my_lock);

Acquisition functions:

void spin_lock(spinlock_t *lock);
void spin_unlock(spinlock_t *lock);

Notes
Spinlock ops are not interruptible
Deadlocks are easy to create