[3.5.y.z extended stable] Patch "mac80211: move "bufferable MMPDU" check to fix AP mode scan" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    mac80211: move "bufferable MMPDU" check to fix AP mode scan

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 1ccb4e69309137ca2ce635d2a8ce6315b9e9fc98 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd at openwrt.org>
Date: Mon, 16 Dec 2013 21:39:50 +0100
Subject: mac80211: move "bufferable MMPDU" check to fix AP mode scan

commit 277d916fc2e959c3f106904116bb4f7b1148d47a upstream.

The check needs to apply to both multicast and unicast packets,
otherwise probe requests on AP mode scans are sent through the multicast
buffer queue, which adds long delays (often longer than the scanning
interval).

Signed-off-by: Felix Fietkau <nbd at openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg at intel.com>
[ luis: backported to 3.5: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/mac80211/tx.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 83755a5..79cfca3 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -446,7 +446,6 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
 {
 	struct sta_info *sta = tx->sta;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
-	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
 	struct ieee80211_local *local = tx->local;

 	if (unlikely(!sta))
@@ -457,15 +456,6 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
 		     !(info->flags & IEEE80211_TX_CTL_NO_PS_BUFFER))) {
 		int ac = skb_get_queue_mapping(tx->skb);

-		/* only deauth, disassoc and action are bufferable MMPDUs */
-		if (ieee80211_is_mgmt(hdr->frame_control) &&
-		    !ieee80211_is_deauth(hdr->frame_control) &&
-		    !ieee80211_is_disassoc(hdr->frame_control) &&
-		    !ieee80211_is_action(hdr->frame_control)) {
-			info->flags |= IEEE80211_TX_CTL_NO_PS_BUFFER;
-			return TX_CONTINUE;
-		}
-
 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
 		printk(KERN_DEBUG "STA %pM aid %d: PS buffer for AC %d\n",
 		       sta->sta.addr, sta->sta.aid, ac);
@@ -514,9 +504,22 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
 static ieee80211_tx_result debug_noinline
 ieee80211_tx_h_ps_buf(struct ieee80211_tx_data *tx)
 {
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
+
 	if (unlikely(tx->flags & IEEE80211_TX_PS_BUFFERED))
 		return TX_CONTINUE;

+	/* only deauth, disassoc and action are bufferable MMPDUs */
+	if (ieee80211_is_mgmt(hdr->frame_control) &&
+	    !ieee80211_is_deauth(hdr->frame_control) &&
+	    !ieee80211_is_disassoc(hdr->frame_control) &&
+	    !ieee80211_is_action(hdr->frame_control)) {
+		if (tx->flags & IEEE80211_TX_UNICAST)
+			info->flags |= IEEE80211_TX_CTL_NO_PS_BUFFER;
+		return TX_CONTINUE;
+	}
+
 	if (tx->flags & IEEE80211_TX_UNICAST)
 		return ieee80211_tx_h_unicast_ps_buf(tx);
 	else
--
1.8.3.2