From c96f9c17f71213a562ce20d85a7418d5549235cc Mon Sep 17 00:00:00 2001 From: Gabor Juhos Date: Fri, 24 Jul 2009 16:34:37 +0200 Subject: [PATCH 1/2] ath9k: fix race with IEEE80211_CONF_PS checks There is a small window where the mac80211 changes the IEEE80211_CONF_PS flag, and then informs the driver about the change. We have a race condition if we are checking the flag in the same time. Avoid it by introducing a local variable, and using that instead of checking the IEEE80211_CONF_PS flag directly. This fix the problem reported by Luis: http://article.gmane.org/gmane.linux.kernel.wireless.general/34363 Changes-licensed-under: ISC Signed-off-by: Gabor Juhos --- drivers/net/wireless/ath/ath9k/ath9k.h | 1 + drivers/net/wireless/ath/ath9k/hw.c | 17 +++++++---------- drivers/net/wireless/ath/ath9k/hw.h | 1 - drivers/net/wireless/ath/ath9k/main.c | 8 ++++---- 4 files changed, 12 insertions(+), 15 deletions(-) --- a/drivers/net/wireless/ath/ath9k/ath9k.h +++ b/drivers/net/wireless/ath/ath9k/ath9k.h @@ -561,6 +561,7 @@ struct ath_softc { u32 keymax; DECLARE_BITMAP(keymap, ATH_KEYMAX); u8 splitmic; + bool ps_enabled; unsigned long ps_usecount; enum ath9k_int imask; enum ath9k_ht_extprotspacing ht_extprotspacing; --- a/drivers/net/wireless/ath/ath9k/hw.c +++ b/drivers/net/wireless/ath/ath9k/hw.c @@ -2793,10 +2793,8 @@ void ath9k_ps_wakeup(struct ath_softc *s if (++sc->ps_usecount != 1) goto unlock; - if (sc->sc_ah->power_mode != ATH9K_PM_AWAKE) { - sc->sc_ah->restore_mode = sc->sc_ah->power_mode; + if (sc->sc_ah->power_mode != ATH9K_PM_AWAKE) ath9k_hw_setpower_nolock(sc->sc_ah, ATH9K_PM_AWAKE); - } unlock: spin_unlock_irqrestore(&sc->sc_pm_lock, flags); @@ -2810,13 +2808,12 @@ void ath9k_ps_restore(struct ath_softc * if (--sc->ps_usecount != 0) goto unlock; - if ((sc->hw->conf.flags & IEEE80211_CONF_PS) && - !(sc->sc_flags & (SC_OP_WAIT_FOR_BEACON | - SC_OP_WAIT_FOR_CAB | - SC_OP_WAIT_FOR_PSPOLL_DATA | - SC_OP_WAIT_FOR_TX_ACK))) - ath9k_hw_setpower_nolock(sc->sc_ah, - sc->sc_ah->restore_mode); + if (sc->ps_enabled && + !(sc->sc_flags & (SC_OP_WAIT_FOR_BEACON | + SC_OP_WAIT_FOR_CAB | + SC_OP_WAIT_FOR_PSPOLL_DATA | + SC_OP_WAIT_FOR_TX_ACK))) + ath9k_hw_setpower_nolock(sc->sc_ah, ATH9K_PM_NETWORK_SLEEP); unlock: spin_unlock_irqrestore(&sc->sc_pm_lock, flags); --- a/drivers/net/wireless/ath/ath9k/hw.h +++ b/drivers/net/wireless/ath/ath9k/hw.h @@ -418,7 +418,6 @@ struct ath_hw { enum nl80211_iftype opmode; enum ath9k_power_mode power_mode; - enum ath9k_power_mode restore_mode; struct ath9k_nfcal_hist nfCalHist[NUM_NF_READINGS]; struct ar5416Stats stats; --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -496,8 +496,7 @@ static void ath9k_tasklet(unsigned long if (status & ATH9K_INT_TX) ath_tx_tasklet(sc); - if ((status & ATH9K_INT_TSFOOR) && - (sc->hw->conf.flags & IEEE80211_CONF_PS)) { + if ((status & ATH9K_INT_TSFOOR) && sc->ps_enabled) { /* * TSF sync does not look correct; remain awake to sync with * the next Beacon. @@ -2001,7 +2000,7 @@ static int ath9k_tx(struct ieee80211_hw goto exit; } - if (sc->hw->conf.flags & IEEE80211_CONF_PS) { + if (sc->ps_enabled) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; /* * mac80211 does not set PM field for normal data frames, so we @@ -2270,8 +2269,9 @@ static int ath9k_config(struct ieee80211 } ath9k_hw_setrxabort(sc->sc_ah, 1); } - ath9k_hw_setpower(sc->sc_ah, ATH9K_PM_NETWORK_SLEEP); + sc->ps_enabled = true; } else { + sc->ps_enabled = false; ath9k_hw_setpower(sc->sc_ah, ATH9K_PM_AWAKE); if (!(ah->caps.hw_caps & ATH9K_HW_CAP_AUTOSLEEP)) {