From 3a5be7d4b079f3a9ce1e8ce4a93ba15ae6d00111 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 18 Jun 2008 01:19:51 -0700 Subject: Revert "mac80211: Use skb_header_cloned() on TX path." This reverts commit 608961a5eca8d3c6bd07172febc27b5559408c5d. The problem is that the mac80211 stack not only needs to be able to muck with the link-level headers, it also might need to mangle all of the packet data if doing sw wireless encryption. This fixes kernel bugzilla #10903. Thanks to Didier Raboud (for the bugzilla report), Andrew Prince (for bisecting), Johannes Berg (for bringing this bisection analysis to my attention), and Ilpo (for trying to analyze this purely from the TCP side). In 2.6.27 we can take another stab at this, by using something like skb_cow_data() when the TX path of mac80211 ends up with a non-NULL tx->key. The ESP protocol code in the IPSEC stack can be used as a model for implementation. Signed-off-by: David S. Miller --- net/mac80211/tx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/mac80211') diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 1d7dd54aace..28d8bd53bd3 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1562,13 +1562,13 @@ int ieee80211_subif_start_xmit(struct sk_buff *skb, * be cloned. This could happen, e.g., with Linux bridge code passing * us broadcast frames. */ - if (head_need > 0 || skb_header_cloned(skb)) { + if (head_need > 0 || skb_cloned(skb)) { #if 0 printk(KERN_DEBUG "%s: need to reallocate buffer for %d bytes " "of headroom\n", dev->name, head_need); #endif - if (skb_header_cloned(skb)) + if (skb_cloned(skb)) I802_DEBUG_INC(local->tx_expand_skb_head_cloned); else I802_DEBUG_INC(local->tx_expand_skb_head); -- cgit From ef3a62d272f033989e83eb1f26505f93f93e3e69 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 18 Jun 2008 15:39:48 -0700 Subject: mac80211: detect driver tx bugs When a driver rejects a frame in it's ->tx() callback, it must also stop queues, otherwise mac80211 can go into a loop here. Detect this situation and abort the loop after five retries, warning about the driver bug. Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- net/mac80211/tx.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'net/mac80211') diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 28d8bd53bd3..c80d5899f27 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1132,7 +1132,7 @@ static int ieee80211_tx(struct net_device *dev, struct sk_buff *skb, ieee80211_tx_handler *handler; struct ieee80211_tx_data tx; ieee80211_tx_result res = TX_DROP, res_prepare; - int ret, i; + int ret, i, retries = 0; WARN_ON(__ieee80211_queue_pending(local, control->queue)); @@ -1216,6 +1216,13 @@ retry: if (!__ieee80211_queue_stopped(local, control->queue)) { clear_bit(IEEE80211_LINK_STATE_PENDING, &local->state[control->queue]); + retries++; + /* + * Driver bug, it's rejecting packets but + * not stopping queues. + */ + if (WARN_ON_ONCE(retries > 5)) + goto drop; goto retry; } memcpy(&store->control, control, -- cgit