mac80211: fix RX aggregation locking
The RX aggregation locking documentation was
wrong, which led Christian to also code the
timer timeout handling for it somewhat wrongly.
Fix the documentation, the two places that
need to hold the reorder lock across accesses
to the structure, and the debugfs code that
should just use RCU.
Also, remove acquiring the sta->lock across
reorder timeouts since it isn't necessary, and
change a few places to GFP_KERNEL because the
code path here doesn't need atomic allocations
as I noticed when reviewing all this.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index d2fcd22..fdeabb1 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -538,6 +538,8 @@
{
struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
+ lockdep_assert_held(&tid_agg_rx->reorder_lock);
+
if (!skb)
goto no_frame;
@@ -557,6 +559,8 @@
{
int index;
+ lockdep_assert_held(&tid_agg_rx->reorder_lock);
+
while (seq_less(tid_agg_rx->head_seq_num, head_seq_num)) {
index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
tid_agg_rx->buf_size;
@@ -581,6 +585,8 @@
{
int index, j;
+ lockdep_assert_held(&tid_agg_rx->reorder_lock);
+
/* release the buffer until next missing frame */
index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
tid_agg_rx->buf_size;
@@ -683,10 +689,11 @@
int index;
bool ret = true;
+ spin_lock(&tid_agg_rx->reorder_lock);
+
buf_size = tid_agg_rx->buf_size;
head_seq_num = tid_agg_rx->head_seq_num;
- spin_lock(&tid_agg_rx->reorder_lock);
/* frame with out of date sequence number */
if (seq_less(mpdu_seq_num, head_seq_num)) {
dev_kfree_skb(skb);
@@ -1921,9 +1928,12 @@
mod_timer(&tid_agg_rx->session_timer,
TU_TO_EXP_TIME(tid_agg_rx->timeout));
+ spin_lock(&tid_agg_rx->reorder_lock);
/* release stored frames up to start of BAR */
ieee80211_release_reorder_frames(hw, tid_agg_rx, start_seq_num,
frames);
+ spin_unlock(&tid_agg_rx->reorder_lock);
+
kfree_skb(skb);
return RX_QUEUED;
}
@@ -2515,9 +2525,8 @@
}
/*
- * This function makes calls into the RX path. Therefore the
- * caller must hold the sta_info->lock and everything has to
- * be under rcu_read_lock protection as well.
+ * This function makes calls into the RX path, therefore
+ * it has to be invoked under RCU read lock.
*/
void ieee80211_release_reorder_timeout(struct sta_info *sta, int tid)
{