mac80211: push rx status into skb->cb

Within mac80211, we often need to copy the rx status into
skb->cb. This is wasteful, as drivers could be building it
in there to start with. This patch changes the API so that
drivers are expected to pass the RX status in skb->cb, now
accessible as IEEE80211_SKB_RXCB(skb). It also updates all
drivers to pass the rx status in there, but only by making
them memcpy() it into place before the call to the receive
function (ieee80211_rx(_irqsafe)). Each driver can now be
optimised on its own schedule.

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

1 files changed, 14 insertions, 15 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index c06104476973..fe80771d95f1 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -397,6 +397,11 @@ static inline struct ieee80211_tx_info *IEEE80211_SKB_CB(struct sk_buff *skb)
         return (struct ieee80211_tx_info *)skb->cb;
 }
 
+static inline struct ieee80211_rx_status *IEEE80211_SKB_RXCB(struct sk_buff *skb)
+{
+        return (struct ieee80211_rx_status *)skb->cb;
+}
+
 /**
  * ieee80211_tx_info_clear_status - clear TX status
  *
@@ -478,7 +483,7 @@ enum mac80211_rx_flags {
  *
  * The low-level driver should provide this information (the subset
  * supported by hardware) to the 802.11 code with each received
- * frame.
+ * frame, in the skb's control buffer (cb).
  *
  * @mactime: value in microseconds of the 64-bit Time Synchronization Function
  *      (TSF) timer when the first data symbol (MPDU) arrived at the hardware.
@@ -1606,9 +1611,11 @@ void ieee80211_free_hw(struct ieee80211_hw *hw);
  */
 void ieee80211_restart_hw(struct ieee80211_hw *hw);
 
-/* trick to avoid symbol clashes with the ieee80211 subsystem */
-void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
-                    struct ieee80211_rx_status *status);
+/*
+ * trick to avoid symbol clashes with the ieee80211 subsystem,
+ * use the inline below instead
+ */
+void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb);
 
 /**
  * ieee80211_rx - receive frame
@@ -1624,13 +1631,10 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
  *
  * @hw: the hardware this frame came in on
  * @skb: the buffer to receive, owned by mac80211 after this call
- * @status: status of this frame; the status pointer need not be valid
- *      after this function returns
  */
-static inline void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
-                                struct ieee80211_rx_status *status)
+static inline void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
-        __ieee80211_rx(hw, skb, status);
+        __ieee80211_rx(hw, skb);
 }
 
 /**
@@ -1644,13 +1648,8 @@ static inline void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
  *
  * @hw: the hardware this frame came in on
  * @skb: the buffer to receive, owned by mac80211 after this call
- * @status: status of this frame; the status pointer need not be valid
- *      after this function returns and is not freed by mac80211,
- *      it is recommended that it points to a stack area
  */
-void ieee80211_rx_irqsafe(struct ieee80211_hw *hw,
-                          struct sk_buff *skb,
-                          struct ieee80211_rx_status *status);
+void ieee80211_rx_irqsafe(struct ieee80211_hw *hw, struct sk_buff *skb);
 
 /**
  * ieee80211_tx_status - transmit status callback