[Ieee80211-devel] [PATCH 20/29] ieee80211 Return NETDEV_TX_BUSY when QoS buffer full

[James K. <jke...@li...>]

Per the conversations with folks at OLS, the QoS layer in 802.11
drivers can now result in NETDEV_TX_BUSY being returned when the queue
a packet is targetted for is full.

To implement this, ieee80211_xmit will now call the driver's
is_queue_full to determine if the current priority queue is full.  If
so, NETDEV_TX_BUSY is returned to the kernel and no processing is done
on the frame.

Signed-off-by: James Ketrenos <jke...@li...>

---

 net/ieee80211/ieee80211_tx.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

4868637e29922d96e049a8817500477075bb87cc
diff --git a/net/ieee80211/ieee80211_tx.c b/net/ieee80211/ieee80211_tx.c
--- a/net/ieee80211/ieee80211_tx.c
+++ b/net/ieee80211/ieee80211_tx.c
@@ -253,6 +253,9 @@ int ieee80211_xmit(struct sk_buff *skb, 
 	int priority = skb->priority;
 	int snapped = 0;
 
+	if (ieee->is_queue_full && (*ieee->is_queue_full) (dev, priority))
+		return NETDEV_TX_BUSY;
+
 	spin_lock_irqsave(&ieee->lock, flags);
 
 	/* If there is no driver handler to take the TXB, dont' bother
@@ -482,6 +485,14 @@ int ieee80211_xmit(struct sk_buff *skb, 
 			stats->tx_bytes += txb->payload_size;
 			return 0;
 		}
+
+		if (ret == NETDEV_TX_BUSY) {
+			printk(KERN_ERR "%s: NETDEV_TX_BUSY returned; "
+			       "driver should report queue full via "
+			       "ieee_device->is_queue_full.\n",
+			       ieee->dev->name);
+		}
+
 		ieee80211_txb_free(txb);
 	}