mac80211: document RCU requirements for ieee80211_tx_dequeue()

In the iwlwifi conversion, we sometimes call this from outside
of the wake_tx_queue() method, and in those cases must be in an
RCU critical section. Document this requirement.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg 2018-12-15 11:03:08 +02:00
parent 233e98dc9c
commit fca1279f09

View file

@ -6103,6 +6103,14 @@ void ieee80211_unreserve_tid(struct ieee80211_sta *sta, u8 tid);
* @txq: pointer obtained from station or virtual interface
*
* Returns the skb if successful, %NULL if no frame was available.
*
* Note that this must be called in an rcu_read_lock() critical section,
* which can only be released after the SKB was handled. Some pointers in
* skb->cb, e.g. the key pointer, are protected by by RCU and thus the
* critical section must persist not just for the duration of this call
* but for the duration of the frame handling.
* However, also note that while in the wake_tx_queue() method,
* rcu_read_lock() is already held.
*/
struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
struct ieee80211_txq *txq);