From: Ilan Peer <ilan.peer@xxxxxxxxx>
When a remain on channel request from mac80211 is followed by
a request to tx a mgmt frame offchannel, it is possible that
the remain on channel expires before the device reported the
tx status for the frame. This causes a race condition in
mac80211.
To fix this, delay the ROC notification to mac80211 until the
device reported the Tx status for all frames in the aux queue.
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx>
Signed-off-by: Ilan Peer <ilan.peer@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
drivers/net/wireless/iwlwifi/iwl-agn-tx.c | 18 ++++++++++
drivers/net/wireless/iwlwifi/iwl-agn.c | 3 ++
drivers/net/wireless/iwlwifi/iwl-agn.h | 5 +++
drivers/net/wireless/iwlwifi/iwl-dev.h | 1 +
drivers/net/wireless/iwlwifi/iwl-scan.c | 51 +++++++++++++++++++++++------
5 files changed, 68 insertions(+), 10 deletions(-)
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index 3366e2e..ad1d36f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -486,6 +486,9 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
if (sta_priv && sta_priv->client && !is_agg)
atomic_inc(&sta_priv->pending_frames);
+ if (info->flags & IEEE80211_TX_CTL_TX_OFFCHAN)
+ iwl_scan_offchannel_skb(priv);
+
return 0;
drop_unlock_sta:
@@ -1136,6 +1139,7 @@ int iwlagn_rx_reply_tx(struct iwl_priv *priv, struct iwl_rx_cmd_buffer *rxb,
struct sk_buff *skb;
struct iwl_rxon_context *ctx;
bool is_agg = (txq_id >= IWLAGN_FIRST_AMPDU_QUEUE);
+ bool is_offchannel_skb;
tid = (tx_resp->ra_tid & IWLAGN_TX_RES_TID_MSK) >>
IWLAGN_TX_RES_TID_POS;
@@ -1149,6 +1153,8 @@ int iwlagn_rx_reply_tx(struct iwl_priv *priv, struct iwl_rx_cmd_buffer *rxb,
__skb_queue_head_init(&skbs);
+ is_offchannel_skb = false;
+
if (tx_resp->frame_count == 1) {
u16 next_reclaimed = le16_to_cpu(tx_resp->seq_ctl);
next_reclaimed = SEQ_TO_SN(next_reclaimed + 0x10);
@@ -1225,10 +1231,19 @@ int iwlagn_rx_reply_tx(struct iwl_priv *priv, struct iwl_rx_cmd_buffer *rxb,
if (!is_agg)
iwlagn_non_agg_tx_status(priv, ctx, hdr->addr1);
+ is_offchannel_skb =
+ (info->flags & IEEE80211_TX_CTL_TX_OFFCHAN);
freed++;
}
WARN_ON(!is_agg && freed != 1);
+
+ /*
+ * An offchannel frame can be send only on the AUX queue, where
+ * there is no aggregation (and reordering) so it only is single
+ * skb is expected to be processed.
+ */
+ WARN_ON(is_offchannel_skb && freed != 1);
}
iwl_check_abort_status(priv, tx_resp->frame_count, status);
@@ -1239,6 +1254,9 @@ int iwlagn_rx_reply_tx(struct iwl_priv *priv, struct iwl_rx_cmd_buffer *rxb,
ieee80211_tx_status(priv->hw, skb);
}
+ if (is_offchannel_skb)
+ iwl_scan_offchannel_skb_status(priv);
+
return 0;
}
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 5149e6f..cd95a240 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -931,6 +931,9 @@ void iwl_down(struct iwl_priv *priv)
priv->ucode_loaded = false;
iwl_trans_stop_device(priv->trans);
+ /* Set num_aux_in_flight must be done after the transport is stopped */
+ atomic_set(&priv->num_aux_in_flight, 0);
+
/* Clear out all status bits but a few that are stable across reset */
priv->status &= test_bit(STATUS_RF_KILL_HW, &priv->status) <<
STATUS_RF_KILL_HW |
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.h b/drivers/net/wireless/iwlwifi/iwl-agn.h
index 79c0fe0..5c1693f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.h
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.h
@@ -101,6 +101,7 @@ extern struct iwl_lib_ops iwl6030_lib;
#define STATUS_CHANNEL_SWITCH_PENDING 11
#define STATUS_SCAN_COMPLETE 12
#define STATUS_POWER_PMI 13
+#define STATUS_SCAN_ROC_EXPIRED 14
struct iwl_ucode_capabilities;
@@ -255,6 +256,10 @@ int __must_check iwl_scan_initiate(struct iwl_priv *priv,
enum iwl_scan_type scan_type,
enum ieee80211_band band);
+void iwl_scan_roc_expired(struct iwl_priv *priv);
+void iwl_scan_offchannel_skb(struct iwl_priv *priv);
+void iwl_scan_offchannel_skb_status(struct iwl_priv *priv);
+
/* For faster active scanning, scan will move to the next channel if fewer than
* PLCP_QUIET_THRESH packets are heard on this channel within
* ACTIVE_QUIET_TIME after sending probe request. This shortens the dwell
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 7006237..a4936a1 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -846,6 +846,7 @@ struct iwl_priv {
struct iwl_station_entry stations[IWLAGN_STATION_COUNT];
unsigned long ucode_key_table;
struct iwl_tid_data tid_data[IWLAGN_STATION_COUNT][IWL_MAX_TID_COUNT];
+ atomic_t num_aux_in_flight;
u8 mac80211_registered;
diff --git a/drivers/net/wireless/iwlwifi/iwl-scan.c b/drivers/net/wireless/iwlwifi/iwl-scan.c
index 031d8e2..eb0ded7 100644
--- a/drivers/net/wireless/iwlwifi/iwl-scan.c
+++ b/drivers/net/wireless/iwlwifi/iwl-scan.c
@@ -101,11 +101,8 @@ static void iwl_complete_scan(struct iwl_priv *priv, bool aborted)
ieee80211_scan_completed(priv->hw, aborted);
}
- if (priv->scan_type == IWL_SCAN_ROC) {
- ieee80211_remain_on_channel_expired(priv->hw);
- priv->hw_roc_channel = NULL;
- schedule_delayed_work(&priv->hw_roc_disable_work, 10 * HZ);
- }
+ if (priv->scan_type == IWL_SCAN_ROC)
+ iwl_scan_roc_expired(priv);
priv->scan_type = IWL_SCAN_NORMAL;
priv->scan_vif = NULL;
@@ -134,11 +131,8 @@ static void iwl_process_scan_complete(struct iwl_priv *priv)
goto out_settings;
}
- if (priv->scan_type == IWL_SCAN_ROC) {
- ieee80211_remain_on_channel_expired(priv->hw);
- priv->hw_roc_channel = NULL;
- schedule_delayed_work(&priv->hw_roc_disable_work, 10 * HZ);
- }
+ if (priv->scan_type == IWL_SCAN_ROC)
+ iwl_scan_roc_expired(priv);
if (priv->scan_type != IWL_SCAN_NORMAL && !aborted) {
int err;
@@ -1158,3 +1152,40 @@ void iwl_cancel_scan_deferred_work(struct iwl_priv *priv)
mutex_unlock(&priv->mutex);
}
}
+
+void iwl_scan_roc_expired(struct iwl_priv *priv)
+{
+ /*
+ * The status bit should be set here, to prevent a race
+ * where the atomic_read returns 1, but before the execution continues
+ * iwl_scan_offchannel_skb_status() checks if the status bit is set
+ */
+ set_bit(STATUS_SCAN_ROC_EXPIRED, &priv->status);
+
+ if (atomic_read(&priv->num_aux_in_flight) == 0) {
+ ieee80211_remain_on_channel_expired(priv->hw);
+ priv->hw_roc_channel = NULL;
+ schedule_delayed_work(&priv->hw_roc_disable_work,
+ 10 * HZ);
+
+ clear_bit(STATUS_SCAN_ROC_EXPIRED, &priv->status);
+ } else {
+ IWL_DEBUG_SCAN(priv, "ROC done with %d frames in aux\n",
+ atomic_read(&priv->num_aux_in_flight));
+ }
+}
+
+void iwl_scan_offchannel_skb(struct iwl_priv *priv)
+{
+ WARN_ON(!priv->hw_roc_start_notified);
+ atomic_inc(&priv->num_aux_in_flight);
+}
+
+void iwl_scan_offchannel_skb_status(struct iwl_priv *priv)
+{
+ if (atomic_dec_return(&priv->num_aux_in_flight) == 0 &&
+ test_bit(STATUS_SCAN_ROC_EXPIRED, &priv->status)) {
+ IWL_DEBUG_SCAN(priv, "0 aux frames. Calling ROC expired\n");
+ iwl_scan_roc_expired(priv);
+ }
+}
--
1.7.10
--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
