[PATCH 2/5] spinlock: Document memory barrier rules for spin_lock and spin_unlock().

In theory, the memory ordering rules for spinlock() and spin_unlock() are simple: spin_lock is ACQUIRE, spin_unlock is RELEASE. What is missing is a clear documentation for the corner cases: - What is covered by the ACQUIRE during spin_lock: only the lock load or also the lock store? -

[PATCH 2/5] spinlock: Document memory barrier rules for spin_lock and spin_unlock().

In theory, the memory ordering rules for spinlock() and spin_unlock() are simple: spin_lock is ACQUIRE, spin_unlock is RELEASE. What is missing is a clear documentation for the corner cases: - What is covered by the ACQUIRE during spin_lock: only the lock load or also the lock store? -