mac80211: fix some key comments and code

 * keys and per-station keys. Since each station belongs to an interface,

 * each station key also belongs to that interface.

 *

 * Hardware acceleration is done on a best-effort basis, for each key

 * that is eligible the hardware is asked to enable that key but if

 * it cannot do that they key is simply kept for software encryption.

 * There is currently no way of knowing this except by looking into

 * debugfs.

 * Hardware acceleration is done on a best-effort basis for algorithms

 * that are implemented in software,  for each key the hardware is asked

 * to enable that key for offloading but if it cannot do that the key is

 * simply kept for software encryption (unless it is for an algorithm

 * that isn't implemented in software).

 * There is currently no way of knowing whether a key is handled in SW

 * or HW except by looking into debugfs.

 *

 * All key operations are protected internally.

 *

 * Within mac80211, key references are, just as STA structure references,

 * protected by RCU. Note, however, that some things are unprotected,

 * namely the key->sta dereferences within the hardware acceleration

 * functions. This means that sta_info_destroy() must remove the key

 * which waits for an RCU grace period.

 * All key management is internally protected by a mutex. Within all

 * other parts of mac80211, key references are, just as STA structure

 * references, protected by RCU. Note, however, that some things are

 * unprotected, namely the key->sta dereferences within the hardware

 * acceleration functions. This means that sta_info_destroy() must

 * remove the key which waits for an RCU grace period.

 */

static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };

							 new->conf.keyidx);

	}

	if (old) {

		/*

		 * We'll use an empty list to indicate that the key

		 * has already been removed.

		 */

		list_del_init(&old->list);

	}

	if (old)

		list_del(&old->list);

}

struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len,

			struct sta_info *ap;

			/*

			 * We're getting a sta pointer in,

			 * so must be under RCU read lock.

			 * We're getting a sta pointer in, so must be under

			 * appropriate locking for sta_info_get().

			 */

			/* same here, the AP could be using QoS */