mac80211: transmit fragment list to drivers

Drivers can usually handle fragmented packets
much easier when they get the entire list of
fragments at once. The only thing they need to
do is keep enough space on the queues for up
to ten fragments of a single MSDU.

This allows them to implement this with a new
operation tx_frags.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 17 insertions, 5 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 0756049ae76..5b5c8a7e26d 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1760,11 +1760,21 @@ enum ieee80211_frame_release_type {
  *	skb contains the buffer starting from the IEEE 802.11 header.
  *	The low-level driver should send the frame out based on
  *	configuration in the TX control data. This handler should,
- *	preferably, never fail and stop queues appropriately, more
- *	importantly, however, it must never fail for A-MPDU-queues.
- *	This function should return NETDEV_TX_OK except in very
- *	limited cases.
- *	Must be implemented and atomic.
+ *	preferably, never fail and stop queues appropriately.
+ *	This must be implemented if @tx_frags is not.
+ *	Must be atomic.
+ *
+ * @tx_frags: Called to transmit multiple fragments of a single MSDU.
+ *	This handler must consume all fragments, sending out some of
+ *	them only is useless and it can't ask for some of them to be
+ *	queued again. If the frame is not fragmented the queue has a
+ *	single SKB only. To avoid issues with the networking stack
+ *	when TX status is reported the frames should be removed from
+ *	the skb queue.
+ *	If this is used, the tx_info @vif and @sta pointers will be
+ *	invalid -- you must not use them in that case.
+ *	This must be implemented if @tx isn't.
+ *	Must be atomic.
  *
  * @start: Called before the first netdevice attached to the hardware
  *	is enabled. This should turn on the hardware and must turn on
@@ -2101,6 +2111,8 @@ enum ieee80211_frame_release_type {
  */
 struct ieee80211_ops {
 	void (*tx)(struct ieee80211_hw *hw, struct sk_buff *skb);
+	void (*tx_frags)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
+			 struct ieee80211_sta *sta, struct sk_buff_head *skbs);
 	int (*start)(struct ieee80211_hw *hw);
 	void (*stop)(struct ieee80211_hw *hw);
 #ifdef CONFIG_PM