package/mac80211/patches/409-ath9k-fix-race-with-IEEE80211_CONF_PS-checks.patch

   1 From c96f9c17f71213a562ce20d85a7418d5549235cc Mon Sep 17 00:00:00 2001
   2 From: Gabor Juhos <juhosg@openwrt.org>
   3 Date: Fri, 24 Jul 2009 16:34:37 +0200
   4 Subject: [PATCH 1/2] ath9k: fix race with IEEE80211_CONF_PS checks
   5
   6 There is a small window where the mac80211 changes the IEEE80211_CONF_PS
   7 flag, and then informs the driver about the change. We have a race
   8 condition if we are checking the flag in the same time. Avoid it by
   9 introducing a local variable, and using that instead of checking the
  10 IEEE80211_CONF_PS flag directly.
  11
  12 This fix the problem reported by Luis:
  13 http://article.gmane.org/gmane.linux.kernel.wireless.general/34363
  14
  15 Changes-licensed-under: ISC
  16 Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
  17 ---
  18  drivers/net/wireless/ath/ath9k/ath9k.h |    1 +
  19  drivers/net/wireless/ath/ath9k/hw.c    |   17 +++++++----------
  20  drivers/net/wireless/ath/ath9k/hw.h    |    1 -
  21  drivers/net/wireless/ath/ath9k/main.c  |    8 ++++----
  22  4 files changed, 12 insertions(+), 15 deletions(-)
  23
  24 --- a/drivers/net/wireless/ath/ath9k/ath9k.h
  25 +++ b/drivers/net/wireless/ath/ath9k/ath9k.h
  26 @@ -561,6 +561,7 @@ struct ath_softc {
  27         u32 keymax;
  28         DECLARE_BITMAP(keymap, ATH_KEYMAX);
  29         u8 splitmic;
  30 +       bool ps_enabled;
  31         unsigned long ps_usecount;
  32         enum ath9k_int imask;
  33         enum ath9k_ht_extprotspacing ht_extprotspacing;
  34 --- a/drivers/net/wireless/ath/ath9k/hw.c
  35 +++ b/drivers/net/wireless/ath/ath9k/hw.c
  36 @@ -2793,10 +2793,8 @@ void ath9k_ps_wakeup(struct ath_softc *s
  37         if (++sc->ps_usecount != 1)
  38                 goto unlock;
  39
  40 -       if (sc->sc_ah->power_mode != ATH9K_PM_AWAKE) {
  41 -               sc->sc_ah->restore_mode = sc->sc_ah->power_mode;
  42 +       if (sc->sc_ah->power_mode != ATH9K_PM_AWAKE)
  43                 ath9k_hw_setpower_nolock(sc->sc_ah, ATH9K_PM_AWAKE);
  44 -       }
  45
  46   unlock:
  47         spin_unlock_irqrestore(&sc->sc_pm_lock, flags);
  48 @@ -2810,13 +2808,12 @@ void ath9k_ps_restore(struct ath_softc *
  49         if (--sc->ps_usecount != 0)
  50                 goto unlock;
  51
  52 -       if ((sc->hw->conf.flags & IEEE80211_CONF_PS) &&
  53 -               !(sc->sc_flags & (SC_OP_WAIT_FOR_BEACON |
  54 -                               SC_OP_WAIT_FOR_CAB |
  55 -                               SC_OP_WAIT_FOR_PSPOLL_DATA |
  56 -                               SC_OP_WAIT_FOR_TX_ACK)))
  57 -               ath9k_hw_setpower_nolock(sc->sc_ah,
  58 -                                     sc->sc_ah->restore_mode);
  59 +       if (sc->ps_enabled &&
  60 +           !(sc->sc_flags & (SC_OP_WAIT_FOR_BEACON |
  61 +                             SC_OP_WAIT_FOR_CAB |
  62 +                             SC_OP_WAIT_FOR_PSPOLL_DATA |
  63 +                             SC_OP_WAIT_FOR_TX_ACK)))
  64 +               ath9k_hw_setpower_nolock(sc->sc_ah, ATH9K_PM_NETWORK_SLEEP);
  65
  66   unlock:
  67         spin_unlock_irqrestore(&sc->sc_pm_lock, flags);
  68 --- a/drivers/net/wireless/ath/ath9k/hw.h
  69 +++ b/drivers/net/wireless/ath/ath9k/hw.h
  70 @@ -418,7 +418,6 @@ struct ath_hw {
  71
  72         enum nl80211_iftype opmode;
  73         enum ath9k_power_mode power_mode;
  74 -       enum ath9k_power_mode restore_mode;
  75
  76         struct ath9k_nfcal_hist nfCalHist[NUM_NF_READINGS];
  77         struct ar5416Stats stats;
  78 --- a/drivers/net/wireless/ath/ath9k/main.c
  79 +++ b/drivers/net/wireless/ath/ath9k/main.c
  80 @@ -496,8 +496,7 @@ static void ath9k_tasklet(unsigned long
  81         if (status & ATH9K_INT_TX)
  82                 ath_tx_tasklet(sc);
  83
  84 -       if ((status & ATH9K_INT_TSFOOR) &&
  85 -           (sc->hw->conf.flags & IEEE80211_CONF_PS)) {
  86 +       if ((status & ATH9K_INT_TSFOOR) && sc->ps_enabled) {
  87                 /*
  88                  * TSF sync does not look correct; remain awake to sync with
  89                  * the next Beacon.
  90 @@ -2001,7 +2000,7 @@ static int ath9k_tx(struct ieee80211_hw
  91                 goto exit;
  92         }
  93
  94 -       if (sc->hw->conf.flags & IEEE80211_CONF_PS) {
  95 +       if (sc->ps_enabled) {
  96                 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
  97                 /*
  98                  * mac80211 does not set PM field for normal data frames, so we
  99 @@ -2270,8 +2269,9 @@ static int ath9k_config(struct ieee80211
 100                                 }
 101                                 ath9k_hw_setrxabort(sc->sc_ah, 1);
 102                         }
 103 -                       ath9k_hw_setpower(sc->sc_ah, ATH9K_PM_NETWORK_SLEEP);
 104 +                       sc->ps_enabled = true;
 105                 } else {
 106 +                       sc->ps_enabled = false;
 107                         ath9k_hw_setpower(sc->sc_ah, ATH9K_PM_AWAKE);
 108                         if (!(ah->caps.hw_caps &
 109                               ATH9K_HW_CAP_AUTOSLEEP)) {