mac80211: serialize rx path workers
This patch addresses the issue of serialization between
the main rx path and various reorder release timers.
<http://www.spinics.net/lists/linux-wireless/msg57214.html>
It converts the previously local "frames" queue into
a global rx queue [rx_skb_queue]. This way, everyone
(be it the main rx-path or some reorder release timeout)
can add frames to it.
Only one active rx handler worker [ieee80211_rx_handlers]
is needed. All other threads which have lost the race of
"runnning_rx_handler" can now simply "return", knowing that
the thread who had the "edge" will also take care of their
workload.
Signed-off-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 260b48b..12cbb4d 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -533,9 +533,9 @@
static void ieee80211_release_reorder_frame(struct ieee80211_hw *hw,
struct tid_ampdu_rx *tid_agg_rx,
- int index,
- struct sk_buff_head *frames)
+ int index)
{
+ struct ieee80211_local *local = hw_to_local(hw);
struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
struct ieee80211_rx_status *status;
@@ -549,7 +549,7 @@
tid_agg_rx->reorder_buf[index] = NULL;
status = IEEE80211_SKB_RXCB(skb);
status->rx_flags |= IEEE80211_RX_DEFERRED_RELEASE;
- __skb_queue_tail(frames, skb);
+ skb_queue_tail(&local->rx_skb_queue, skb);
no_frame:
tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num);
@@ -557,8 +557,7 @@
static void ieee80211_release_reorder_frames(struct ieee80211_hw *hw,
struct tid_ampdu_rx *tid_agg_rx,
- u16 head_seq_num,
- struct sk_buff_head *frames)
+ u16 head_seq_num)
{
int index;
@@ -567,7 +566,7 @@
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;
- ieee80211_release_reorder_frame(hw, tid_agg_rx, index, frames);
+ ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
}
}
@@ -583,8 +582,7 @@
#define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)
static void ieee80211_sta_reorder_release(struct ieee80211_hw *hw,
- struct tid_ampdu_rx *tid_agg_rx,
- struct sk_buff_head *frames)
+ struct tid_ampdu_rx *tid_agg_rx)
{
int index, j;
@@ -615,8 +613,7 @@
wiphy_debug(hw->wiphy,
"release an RX reorder frame due to timeout on earlier frames\n");
#endif
- ieee80211_release_reorder_frame(hw, tid_agg_rx,
- j, frames);
+ ieee80211_release_reorder_frame(hw, tid_agg_rx, j);
/*
* Increment the head seq# also for the skipped slots.
@@ -626,7 +623,7 @@
skipped = 0;
}
} else while (tid_agg_rx->reorder_buf[index]) {
- ieee80211_release_reorder_frame(hw, tid_agg_rx, index, frames);
+ ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
tid_agg_rx->buf_size;
}
@@ -682,8 +679,7 @@
*/
static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
struct tid_ampdu_rx *tid_agg_rx,
- struct sk_buff *skb,
- struct sk_buff_head *frames)
+ struct sk_buff *skb)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
u16 sc = le16_to_cpu(hdr->seq_ctrl);
@@ -710,8 +706,7 @@
if (!seq_less(mpdu_seq_num, head_seq_num + buf_size)) {
head_seq_num = seq_inc(seq_sub(mpdu_seq_num, buf_size));
/* release stored frames up to new head to stack */
- ieee80211_release_reorder_frames(hw, tid_agg_rx, head_seq_num,
- frames);
+ ieee80211_release_reorder_frames(hw, tid_agg_rx, head_seq_num);
}
/* Now the new frame is always in the range of the reordering buffer */
@@ -739,7 +734,7 @@
tid_agg_rx->reorder_buf[index] = skb;
tid_agg_rx->reorder_time[index] = jiffies;
tid_agg_rx->stored_mpdu_num++;
- ieee80211_sta_reorder_release(hw, tid_agg_rx, frames);
+ ieee80211_sta_reorder_release(hw, tid_agg_rx);
out:
spin_unlock(&tid_agg_rx->reorder_lock);
@@ -750,8 +745,7 @@
* Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
* true if the MPDU was buffered, false if it should be processed.
*/
-static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx,
- struct sk_buff_head *frames)
+static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx)
{
struct sk_buff *skb = rx->skb;
struct ieee80211_local *local = rx->local;
@@ -806,11 +800,11 @@
* sure that we cannot get to it any more before doing
* anything with it.
*/
- if (ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb, frames))
+ if (ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb))
return;
dont_reorder:
- __skb_queue_tail(frames, skb);
+ skb_queue_tail(&local->rx_skb_queue, skb);
}
static ieee80211_rx_result debug_noinline
@@ -1931,7 +1925,7 @@
}
static ieee80211_rx_result debug_noinline
-ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx, struct sk_buff_head *frames)
+ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx)
{
struct ieee80211_local *local = rx->local;
struct ieee80211_hw *hw = &local->hw;
@@ -1971,8 +1965,7 @@
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);
+ ieee80211_release_reorder_frames(hw, tid_agg_rx, start_seq_num);
spin_unlock(&tid_agg_rx->reorder_lock);
kfree_skb(skb);
@@ -2489,8 +2482,7 @@
}
}
-static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx,
- struct sk_buff_head *frames)
+static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx)
{
ieee80211_rx_result res = RX_DROP_MONITOR;
struct sk_buff *skb;
@@ -2502,7 +2494,15 @@
goto rxh_next; \
} while (0);
- while ((skb = __skb_dequeue(frames))) {
+ spin_lock(&rx->local->rx_skb_queue.lock);
+ if (rx->local->running_rx_handler)
+ goto unlock;
+
+ rx->local->running_rx_handler = true;
+
+ while ((skb = __skb_dequeue(&rx->local->rx_skb_queue))) {
+ spin_unlock(&rx->local->rx_skb_queue.lock);
+
/*
* all the other fields are valid across frames
* that belong to an aMPDU since they are on the
@@ -2525,12 +2525,7 @@
CALL_RXH(ieee80211_rx_h_mesh_fwding);
#endif
CALL_RXH(ieee80211_rx_h_data)
-
- /* special treatment -- needs the queue */
- res = ieee80211_rx_h_ctrl(rx, frames);
- if (res != RX_CONTINUE)
- goto rxh_next;
-
+ CALL_RXH(ieee80211_rx_h_ctrl);
CALL_RXH(ieee80211_rx_h_mgmt_check)
CALL_RXH(ieee80211_rx_h_action)
CALL_RXH(ieee80211_rx_h_userspace_mgmt)
@@ -2539,18 +2534,20 @@
rxh_next:
ieee80211_rx_handlers_result(rx, res);
-
+ spin_lock(&rx->local->rx_skb_queue.lock);
#undef CALL_RXH
}
+
+ rx->local->running_rx_handler = false;
+
+ unlock:
+ spin_unlock(&rx->local->rx_skb_queue.lock);
}
static void ieee80211_invoke_rx_handlers(struct ieee80211_rx_data *rx)
{
- struct sk_buff_head reorder_release;
ieee80211_rx_result res = RX_DROP_MONITOR;
- __skb_queue_head_init(&reorder_release);
-
#define CALL_RXH(rxh) \
do { \
res = rxh(rx); \
@@ -2561,9 +2558,9 @@
CALL_RXH(ieee80211_rx_h_passive_scan)
CALL_RXH(ieee80211_rx_h_check)
- ieee80211_rx_reorder_ampdu(rx, &reorder_release);
+ ieee80211_rx_reorder_ampdu(rx);
- ieee80211_rx_handlers(rx, &reorder_release);
+ ieee80211_rx_handlers(rx);
return;
rxh_next:
@@ -2578,7 +2575,6 @@
*/
void ieee80211_release_reorder_timeout(struct sta_info *sta, int tid)
{
- struct sk_buff_head frames;
struct ieee80211_rx_data rx = {
.sta = sta,
.sdata = sta->sdata,
@@ -2591,13 +2587,11 @@
if (!tid_agg_rx)
return;
- __skb_queue_head_init(&frames);
-
spin_lock(&tid_agg_rx->reorder_lock);
- ieee80211_sta_reorder_release(&sta->local->hw, tid_agg_rx, &frames);
+ ieee80211_sta_reorder_release(&sta->local->hw, tid_agg_rx);
spin_unlock(&tid_agg_rx->reorder_lock);
- ieee80211_rx_handlers(&rx, &frames);
+ ieee80211_rx_handlers(&rx);
}
/* main receive path */