mac80211: synchronously reserve TID per station

In TDLS (e.g., TDLS off-channel) there is a requirement for
some drivers to supply an unused TID between the AP and the
device to the FW, to allow sending PTI requests and to allow
the FW to aggregate on a specific TID for better throughput.

To ensure that the allocated TID is indeed unused, this patch
introduces an API for blocking the driver from TXing on that
TID.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 56b7e2114728..59166a115aff 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -5071,6 +5071,43 @@ void ieee80211_tdls_oper_request(struct ieee80211_vif *vif, const u8 *peer,
 				 u16 reason_code, gfp_t gfp);
 
 /**
+ * ieee80211_reserve_tid - request to reserve a specific TID
+ *
+ * There is sometimes a need (such as in TDLS) for blocking the driver from
+ * using a specific TID so that the FW can use it for certain operations such
+ * as sending PTI requests. To make sure that the driver doesn't use that TID,
+ * this function must be called as it flushes out packets on this TID and marks
+ * it as blocked, so that any transmit for the station on this TID will be
+ * redirected to the alternative TID in the same AC.
+ *
+ * Note that this function blocks and may call back into the driver, so it
+ * should be called without driver locks held. Also note this function should
+ * only be called from the driver's @sta_state callback.
+ *
+ * @sta: the station to reserve the TID for
+ * @tid: the TID to reserve
+ *
+ * Returns: 0 on success, else on failure
+ */
+int ieee80211_reserve_tid(struct ieee80211_sta *sta, u8 tid);
+
+/**
+ * ieee80211_unreserve_tid - request to unreserve a specific TID
+ *
+ * Once there is no longer any need for reserving a certain TID, this function
+ * should be called, and no longer will packets have their TID modified for
+ * preventing use of this TID in the driver.
+ *
+ * Note that this function blocks and acquires a lock, so it should be called
+ * without driver locks held. Also note this function should only be called
+ * from the driver's @sta_state callback.
+ *
+ * @sta: the station
+ * @tid: the TID to unreserve
+ */
+void ieee80211_unreserve_tid(struct ieee80211_sta *sta, u8 tid);
+
+/**
  * ieee80211_ie_split - split an IE buffer according to ordering
  *
  * @ies: the IE buffer