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Commit 96148326 authored by Gabor Juhos's avatar Gabor Juhos Committed by John W. Linville
Browse files

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: default avatarGabor Juhos <juhosg@openwrt.org>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent ff8365ca

drivers/net/wireless/ath/ath9k/ath9k.h

+1 −0
Original line number Diff line number Diff line
@@ -573,6 +573,7 @@ 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;

drivers/net/wireless/ath/ath9k/hw.c

+7 −10
Original line number Diff line number Diff line
@@ -2863,10 +2863,8 @@ void ath9k_ps_wakeup(struct ath_softc *sc) 
	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);
@@ -2880,13 +2878,12 @@ void ath9k_ps_restore(struct ath_softc *sc) 
	if (--sc->ps_usecount != 0)

		goto unlock;



	if ((sc->hw->conf.flags & IEEE80211_CONF_PS) &&

	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,

				      sc->sc_ah->restore_mode);

		ath9k_hw_setpower_nolock(sc->sc_ah, ATH9K_PM_NETWORK_SLEEP);



 unlock:

	spin_unlock_irqrestore(&sc->sc_pm_lock, flags);

drivers/net/wireless/ath/ath9k/hw.h

+0 −1
Original line number Diff line number Diff line
@@ -421,7 +421,6 @@ 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;

drivers/net/wireless/ath/ath9k/main.c

+4 −4
Original line number Diff line number Diff line
@@ -499,8 +499,7 @@ static void ath9k_tasklet(unsigned long data) 
	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 *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
@@ -2289,8 +2288,9 @@ static int ath9k_config(struct ieee80211_hw *hw, u32 changed) 
				}

				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)) {