Commit:     2a8a9a88fc1b18f5c45244d0ef8a5352f6cf761f
Parent:     4b6aa59999a3a12dd4740a52299c6c33e85a8747
Author:     Johannes Berg <[EMAIL PROTECTED]>
AuthorDate: Tue Aug 28 17:01:52 2007 -0400
Committer:  David S. Miller <[EMAIL PROTECTED]>
CommitDate: Wed Oct 10 16:48:39 2007 -0700

    [MAC80211]: avoid copying packets to interfaces that are down
    David Woodhouse noticed that under some circumstances the number of slab
    allocations kept growing. After looking a bit, this seemed to happen
    when you had a management mode interface that was *down*.
    The reason for this is that when the device is down, all management
    frames get queued to the in-kernel MLME (via ieee80211_sta_rx_mgmt) but
    then the sta work is invoked but doesn't run when the netif is down.
    When you then bring the interface up, all such frames are freed, but if
    you change the mode all of them are lost because the skb queue is
    reinitialised as soon as you go back to managed mode. The skb queue is
    correctly cleared when the interface is brought down, but the code
    doesn't account for the fact that it may be filled while it is not up.
    This patch should fix the issue by simply ignoring all interfaces that
    are down when going through the RX handlers.
    Signed-off-by: Johannes Berg <[EMAIL PROTECTED]>
    Acked-by: Michael Wu <[EMAIL PROTECTED]>
    Signed-off-by: John W. Linville <[EMAIL PROTECTED]>
    Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
 net/mac80211/ieee80211.c |    9 +++++++++
 net/mac80211/rx.c        |    3 +++
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index 5fc2402..00df2a9 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -493,7 +493,16 @@ static void ieee80211_if_shutdown(struct net_device *dev)
        case IEEE80211_IF_TYPE_IBSS:
                sdata->u.sta.state = IEEE80211_DISABLED;
+               /*
+                * Holding the sub_if_lock for writing here blocks
+                * out the receive path and makes sure it's not
+                * currently processing a packet that may get
+                * added to the queue.
+                */
+               write_lock_bh(&local->sub_if_lock);
+               write_unlock_bh(&local->sub_if_lock);
                if (!local->ops->hw_scan &&
                    local->scan_dev == sdata->dev) {
                        local->sta_scanning = 0;
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 95a00eb..01176ba 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1380,6 +1380,9 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct 
sk_buff *skb,
        list_for_each_entry(sdata, &local->sub_if_list, list) {
                rx.u.rx.ra_match = 1;
+               if (!netif_running(sdata->dev))
+                       continue;
                prepres = prepare_for_handlers(sdata, bssid, &rx, hdr);
                /* prepare_for_handlers can change sta */
                sta = rx.sta;
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