[PATCH 3.12 12/82] ath9k_htc: make ->sta_rc_update atomic for most calls

Greg Kroah-Hartman
2014-02-21T00:44:24Z

From: Stanislaw Gruszka <sgruszka@redhat.com>

commit 2fa4cb905605c863bf570027233af7afd8149ae4 upstream.

sta_rc_update() callback must be atomic, hence we can not take mutexes
or do other operations, which can sleep in ath9k_htc_sta_rc_update().

I think we can just return from ath9k_htc_sta_rc_update(), if it is
called without IEEE80211_RC_SUPP_RATES_CHANGED bit. That will help
with scheduling while atomic bug for most cases (except mesh and IBSS
modes).

For mesh and IBSS I do not see other solution like creating additional
workqueue, because sending firmware command require us to sleep, but
this can be done in additional patch.

Patch partially fixes bug:
https://bugzilla.redhat.com/show_bug.cgi?id=990955

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/wireless/ath/ath9k/htc_drv_main.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)

--- a/drivers/net/wireless/ath/ath9k/htc_drv_main.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
@@ -1337,21 +1337,22 @@ static void ath9k_htc_sta_rc_update(stru
struct ath_common *common = ath9k_hw_common(priv->ah);
struct ath9k_htc_target_rate trate;

+ if (!(changed & IEEE80211_RC_SUPP_RATES_CHANGED))
+ return;
+
mutex_lock(&priv->mutex);
ath9k_htc_ps_wakeup(priv);

- if (changed & IEEE80211_RC_SUPP_RATES_CHANGED) {
- memset(&trate, 0, sizeof(struct ath9k_htc_target_rate));
- ath9k_htc_setup_rate(priv, sta, &trate);
- if (!ath9k_htc_send_rate_cmd(priv, &trate))
- ath_dbg(common, CONFIG,
- "Supported rates for sta: %pM updated, rate caps: 0x%X\n",
- sta->addr, be32_to_cpu(trate.capflags));
- else
- ath_dbg(common, CONFIG,
- "Unable to update supported rates for sta: %pM\n",
- sta->addr);
- }
+ memset(&trate, 0, sizeof(struct ath9k_htc_target_rate));
+ ath9k_htc_setup_rate(priv, sta, &trate);
+ if (!ath9k_htc_send_rate_cmd(priv, &trate))
+ ath_dbg(common, CONFIG,
+ "Supported rates for sta: %pM updated, rate caps: 0x%X\n",
+ sta->addr, be32_to_cpu(trate.capflags));
+ else
+ ath_dbg(common, CONFIG,
+ "Unable to update supported rates for sta: %pM\n",
+ sta->addr);

ath9k_htc_ps_restore(priv);
mutex_unlock(&priv->mutex);