Re: [PATCH] mac80211: Fix bug in getting rx status for frames pending in reorder buffer

[Vasanthakumar Thiagarajan <vasanth@atheros.com>]

On Wed, Mar 25, 2009 at 04:32:53PM +0530, Johannes Berg wrote:
> On Wed, 2009-03-25 at 16:23 +0530, Vasanthakumar Thiagarajan wrote:
> > Currently rx status for frames which are completed from reorder buffer
> > is taken from it's cb area which is wrong, cb is not holding the rx status.
> > This results in dropping almost all frames from reorder buffer when security
> > is enabled by doing double decryption (first in hw, second in sw because of wrong
> > rx status). This patch copies rx status into cb area before the frame is put
> > into reorder buffer. After this patch, there is a significant improvement in
> > throughput with ath9k + WPA2(AES).
> 
> Interesting. For ieee80211_rx_irqsafe() packets this is already in the
> cb area.

right. I will change the commit log.
> 
> I've been pondering for a while just requiring drivers to put it in
> there to start with -- thoughts?

I'm not seeing any reason fot not doing this in the driver itself.
> 
> What's the case where the Rx status is NULL?

This is while completing reorder buffer on reception of BAR.
> 
> johannes
> 
> > Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
> > ---
> >  net/mac80211/rx.c |   13 +++++++++----
> >  1 files changed, 9 insertions(+), 4 deletions(-)
> > 
> > diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
> > index 64ebe66..5fa7aed 100644
> > --- a/net/mac80211/rx.c
> > +++ b/net/mac80211/rx.c
> > @@ -29,6 +29,7 @@
> >  static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
> >  					   struct tid_ampdu_rx *tid_agg_rx,
> >  					   struct sk_buff *skb,
> > +					   struct ieee80211_rx_status *status,
> >  					   u16 mpdu_seq_num,
> >  					   int bar_req);
> >  /*
> > @@ -1688,7 +1689,7 @@ ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx)
> >  		/* manage reordering buffer according to requested */
> >  		/* sequence number */
> >  		rcu_read_lock();
> > -		ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, NULL,
> > +		ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, NULL, NULL,
> >  						 start_seq_num, 1);
> >  		rcu_read_unlock();
> >  		return RX_DROP_UNUSABLE;
> > @@ -2293,6 +2294,7 @@ static inline u16 seq_sub(u16 sq1, u16 sq2)
> >  static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
> >  					   struct tid_ampdu_rx *tid_agg_rx,
> >  					   struct sk_buff *skb,
> > +					   struct ieee80211_rx_status *rxstatus,
> >  					   u16 mpdu_seq_num,
> >  					   int bar_req)
> >  {
> > @@ -2374,6 +2376,8 @@ static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
> >  
> >  	/* put the frame in the reordering buffer */
> >  	tid_agg_rx->reorder_buf[index] = skb;
> > +	memcpy(tid_agg_rx->reorder_buf[index]->cb, rxstatus,
> > +	       sizeof(*rxstatus));
> >  	tid_agg_rx->stored_mpdu_num++;
> >  	/* release the buffer until next missing frame */
> >  	index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn)
> > @@ -2399,7 +2403,8 @@ static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
> >  }
> >  
> >  static u8 ieee80211_rx_reorder_ampdu(struct ieee80211_local *local,
> > -				     struct sk_buff *skb)
> > +				     struct sk_buff *skb,
> > +				     struct ieee80211_rx_status *status)
> >  {
> >  	struct ieee80211_hw *hw = &local->hw;
> >  	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
> > @@ -2448,7 +2453,7 @@ static u8 ieee80211_rx_reorder_ampdu(struct ieee80211_local *local,
> >  
> >  	/* according to mpdu sequence number deal with reordering buffer */
> >  	mpdu_seq_num = (sc & IEEE80211_SCTL_SEQ) >> 4;
> > -	ret = ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb,
> > +	ret = ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb, status,
> >  						mpdu_seq_num, 0);
> >   end_reorder:
> >  	return ret;
> > @@ -2512,7 +2517,7 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
> >  		return;
> >  	}
> >  
> > -	if (!ieee80211_rx_reorder_ampdu(local, skb))
> > +	if (!ieee80211_rx_reorder_ampdu(local, skb, status))
> >  		__ieee80211_rx_handle_packet(hw, skb, status, rate);
> >  
> >  	rcu_read_unlock();