From bca7bafbe2b75ed31cc6943b81218ea0f8a13686 Mon Sep 17 00:00:00 2001 From: Michal Kazior Date: Mon, 26 May 2014 12:46:03 +0300 Subject: [PATCH] ath10k: drain tx before restarting hw This makes sure no further tx requests are submitted to HTT before driver teardown. This should prevent invalid pointer/NULL dereference on htt tx pool in ath10k_htt_tx() in some cases of heavy traffic. kvalo: remove the WARN_ON() if conf_mutex is held Reported-By: Ben Greear Signed-off-by: Michal Kazior Signed-off-by: Kalle Valo --- drivers/net/wireless/ath/ath10k/mac.c | 31 ++++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-) diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c index d73f146..8ad03d5 100644 --- a/drivers/net/wireless/ath/ath10k/mac.c +++ b/drivers/net/wireless/ath/ath10k/mac.c @@ -2289,9 +2289,19 @@ static void ath10k_tx(struct ieee80211_hw *hw, ath10k_tx_htt(ar, skb); } -/* - * Initialize various parameters with default vaules. - */ +/* Must not be called with conf_mutex held as workers can use that also. */ +static void ath10k_drain_tx(struct ath10k *ar) +{ + /* make sure rcu-protected mac80211 tx path itself is drained */ + synchronize_net(); + + ath10k_offchan_tx_purge(ar); + ath10k_mgmt_over_wmi_tx_purge(ar); + + cancel_work_sync(&ar->offchan_tx_work); + cancel_work_sync(&ar->wmi_mgmt_tx_work); +} + void ath10k_halt(struct ath10k *ar) { struct ath10k_vif *arvif; @@ -2307,8 +2317,6 @@ void ath10k_halt(struct ath10k *ar) del_timer_sync(&ar->scan.timeout); ath10k_reset_scan((unsigned long)ar); - ath10k_offchan_tx_purge(ar); - ath10k_mgmt_over_wmi_tx_purge(ar); ath10k_peer_cleanup_all(ar); ath10k_core_stop(ar); ath10k_hif_power_down(ar); @@ -2394,6 +2402,13 @@ static int ath10k_start(struct ieee80211_hw *hw) struct ath10k *ar = hw->priv; int ret = 0; + /* + * This makes sense only when restarting hw. It is harmless to call + * uncoditionally. This is necessary to make sure no HTT/WMI tx + * commands will be submitted while restarting. + */ + ath10k_drain_tx(ar); + mutex_lock(&ar->conf_mutex); switch (ar->state) { @@ -2481,6 +2496,8 @@ static void ath10k_stop(struct ieee80211_hw *hw) { struct ath10k *ar = hw->priv; + ath10k_drain_tx(ar); + mutex_lock(&ar->conf_mutex); if (ar->state != ATH10K_STATE_OFF) { ath10k_halt(ar); @@ -2488,10 +2505,6 @@ static void ath10k_stop(struct ieee80211_hw *hw) } mutex_unlock(&ar->conf_mutex); - ath10k_mgmt_over_wmi_tx_purge(ar); - - cancel_work_sync(&ar->offchan_tx_work); - cancel_work_sync(&ar->wmi_mgmt_tx_work); cancel_work_sync(&ar->restart_work); } -- 2.7.4