Re: [PATCH 1/2] iwlagn: fix channel switch locking

Re: [PATCH 1/2] iwlagn: fix channel switch locking

[Guy, Wey-Yi]

Hi Stanislaw,

On Thu, 2011-06-02 at 07:44 -0700, Stanislaw Gruszka wrote:
> We use priv->mutex to avoid race condtions between iwl_chswitch_done()
> and iwlagn_mac_channel_switch(), when marking channel switch in
> progress. But iwl_chswitch_dane() can be called in atomic context
> from iwl_rx_csa() or with mutex already taken from iwlagn_commit_rxon().
> 
> These bugs were introduced by:
> 
> commit 79d07325502e73508f917475bc1617b60979dd94
> Author: Wey-Yi Guy <wey-yi.w.guy@intel.com>
> Date:   Thu May 6 08:54:11 2010 -0700
> 
>     iwlwifi: support channel switch offload in driver
> 
> To fix remove mutex from iwl_chswitch_done() and use atomic bitops for
> marking channel switch pending.
> 
> Cc: stable@kernel.org # 2.6.36+
> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
> ---
>  drivers/net/wireless/iwlwifi/iwl-2000.c     |    2 --
>  drivers/net/wireless/iwlwifi/iwl-5000.c     |    2 --
>  drivers/net/wireless/iwlwifi/iwl-6000.c     |    2 --
>  drivers/net/wireless/iwlwifi/iwl-agn-rxon.c |    6 +++---
>  drivers/net/wireless/iwlwifi/iwl-agn.c      |   19 ++++++++++---------
>  drivers/net/wireless/iwlwifi/iwl-core.c     |    6 +-----
>  drivers/net/wireless/iwlwifi/iwl-core.h     |    1 +
>  drivers/net/wireless/iwlwifi/iwl-dev.h      |   13 +------------
>  drivers/net/wireless/iwlwifi/iwl-rx.c       |   24 ++++++++++++------------
>  9 files changed, 28 insertions(+), 47 deletions(-)
> 
> diff --git a/drivers/net/wireless/iwlwifi/iwl-2000.c b/drivers/net/wireless/iwlwifi/iwl-2000.c
> index a37c41b..33f0ad9 100644
> --- a/drivers/net/wireless/iwlwifi/iwl-2000.c
> +++ b/drivers/net/wireless/iwlwifi/iwl-2000.c
> @@ -244,8 +244,6 @@ static int iwl2030_hw_channel_switch(struct iwl_priv *priv,
>  			ctx->active.channel, ch);
>  		return -EFAULT;
>  	}
> -	priv->switch_rxon.channel = cmd.channel;
> -	priv->switch_rxon.switch_in_progress = true;
>  
>  	return iwl_send_cmd_sync(priv, &hcmd);
>  }
Thank you for fix my mistake.
Could you please remove the channel switch from iwl-2000.c all together.
2000 series are 2.4 GHz only 

Thanks
Wey

Re: [PATCH 2/2] iwlagn: refactor iwlagn_mac_channel_switch

[Guy, Wey-Yi]

On Thu, 2011-06-02 at 07:46 -0700, Stanislaw Gruszka wrote:
> Use less indentions and remove uneeded irq-save flags.
> 
> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

> ---
>  drivers/net/wireless/iwlwifi/iwl-agn.c |  106 ++++++++++++++++----------------
>  1 files changed, 52 insertions(+), 54 deletions(-)
> 

[PATCH 1/2] iwlagn: fix channel switch locking

[Stanislaw Gruszka]

We use priv->mutex to avoid race condtions between iwl_chswitch_done()
and iwlagn_mac_channel_switch(), when marking channel switch in
progress. But iwl_chswitch_dane() can be called in atomic context
from iwl_rx_csa() or with mutex already taken from iwlagn_commit_rxon().

These bugs were introduced by:

commit 79d07325502e73508f917475bc1617b60979dd94
Author: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Date:   Thu May 6 08:54:11 2010 -0700

    iwlwifi: support channel switch offload in driver

To fix remove mutex from iwl_chswitch_done() and use atomic bitops for
marking channel switch pending.

Cc: stable@kernel.org # 2.6.36+
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
---
 drivers/net/wireless/iwlwifi/iwl-2000.c     |    2 --
 drivers/net/wireless/iwlwifi/iwl-5000.c     |    2 --
 drivers/net/wireless/iwlwifi/iwl-6000.c     |    2 --
 drivers/net/wireless/iwlwifi/iwl-agn-rxon.c |    6 +++---
 drivers/net/wireless/iwlwifi/iwl-agn.c      |   19 ++++++++++---------
 drivers/net/wireless/iwlwifi/iwl-core.c     |    6 +-----
 drivers/net/wireless/iwlwifi/iwl-core.h     |    1 +
 drivers/net/wireless/iwlwifi/iwl-dev.h      |   13 +------------
 drivers/net/wireless/iwlwifi/iwl-rx.c       |   24 ++++++++++++------------
 9 files changed, 28 insertions(+), 47 deletions(-)

diff --git a/drivers/net/wireless/iwlwifi/iwl-2000.c b/drivers/net/wireless/iwlwifi/iwl-2000.c
index a37c41b..33f0ad9 100644
--- a/drivers/net/wireless/iwlwifi/iwl-2000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-2000.c
@@ -244,8 +244,6 @@ static int iwl2030_hw_channel_switch(struct iwl_priv *priv,
 			ctx->active.channel, ch);
 		return -EFAULT;
 	}
-	priv->switch_rxon.channel = cmd.channel;
-	priv->switch_rxon.switch_in_progress = true;
 
 	return iwl_send_cmd_sync(priv, &hcmd);
 }
diff --git a/drivers/net/wireless/iwlwifi/iwl-5000.c b/drivers/net/wireless/iwlwifi/iwl-5000.c
index a8dbbd0..32028b1 100644
--- a/drivers/net/wireless/iwlwifi/iwl-5000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-5000.c
@@ -331,8 +331,6 @@ static int iwl5000_hw_channel_switch(struct iwl_priv *priv,
 			ctx->active.channel, ch);
 		return -EFAULT;
 	}
-	priv->switch_rxon.channel = cmd.channel;
-	priv->switch_rxon.switch_in_progress = true;
 
 	return iwl_send_cmd_sync(priv, &hcmd);
 }
diff --git a/drivers/net/wireless/iwlwifi/iwl-6000.c b/drivers/net/wireless/iwlwifi/iwl-6000.c
index 0e127a7..6e5ce44 100644
--- a/drivers/net/wireless/iwlwifi/iwl-6000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-6000.c
@@ -270,8 +270,6 @@ static int iwl6000_hw_channel_switch(struct iwl_priv *priv,
 			ctx->active.channel, ch);
 		return -EFAULT;
 	}
-	priv->switch_rxon.channel = cmd.channel;
-	priv->switch_rxon.switch_in_progress = true;
 
 	return iwl_send_cmd_sync(priv, &hcmd);
 }
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c b/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
index afb2f20..c263638 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
@@ -370,10 +370,10 @@ int iwlagn_commit_rxon(struct iwl_priv *priv, struct iwl_rxon_context *ctx)
 	 * receive commit_rxon request
 	 * abort any previous channel switch if still in process
 	 */
-	if (priv->switch_rxon.switch_in_progress &&
-	    (priv->switch_rxon.channel != ctx->staging.channel)) {
+	if (test_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status) &&
+	    (priv->switch_channel != ctx->staging.channel)) {
 		IWL_DEBUG_11H(priv, "abort channel switch on %d\n",
-		      le16_to_cpu(priv->switch_rxon.channel));
+			      le16_to_cpu(priv->switch_channel));
 		iwl_chswitch_done(priv, false);
 	}
 
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 58fd367..1a143b2 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2843,16 +2843,13 @@ static void iwlagn_mac_channel_switch(struct ieee80211_hw *hw,
 		goto out;
 
 	if (test_bit(STATUS_EXIT_PENDING, &priv->status) ||
-	    test_bit(STATUS_SCANNING, &priv->status))
+	    test_bit(STATUS_SCANNING, &priv->status) ||
+	    test_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status))
 		goto out;
 
 	if (!iwl_is_associated_ctx(ctx))
 		goto out;
 
-	/* channel switch in progress */
-	if (priv->switch_rxon.switch_in_progress == true)
-		goto out;
-
 	if (priv->cfg->ops->lib->set_channel_switch) {
 
 		ch = channel->hw_value;
@@ -2901,15 +2898,19 @@ static void iwlagn_mac_channel_switch(struct ieee80211_hw *hw,
 			 * at this point, staging_rxon has the
 			 * configuration for channel switch
 			 */
+			set_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status);
+			priv->switch_channel = cpu_to_le16(ch);
 			if (priv->cfg->ops->lib->set_channel_switch(priv,
-								    ch_switch))
-				priv->switch_rxon.switch_in_progress = false;
+								    ch_switch)) {
+				clear_bit(STATUS_CHANNEL_SWITCH_PENDING,
+					  &priv->status);
+				priv->switch_channel = 0;
+				ieee80211_chswitch_done(ctx->vif, false);
+			}
 		}
 	}
 out:
 	mutex_unlock(&priv->mutex);
-	if (!priv->switch_rxon.switch_in_progress)
-		ieee80211_chswitch_done(ctx->vif, false);
 	IWL_DEBUG_MAC80211(priv, "leave\n");
 }
 
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c b/drivers/net/wireless/iwlwifi/iwl-core.c
index 52e9413..70e6fd1 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.c
+++ b/drivers/net/wireless/iwlwifi/iwl-core.c
@@ -843,12 +843,8 @@ void iwl_chswitch_done(struct iwl_priv *priv, bool is_success)
 	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 		return;
 
-	if (priv->switch_rxon.switch_in_progress) {
+	if (test_and_clear_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status))
 		ieee80211_chswitch_done(ctx->vif, is_success);
-		mutex_lock(&priv->mutex);
-		priv->switch_rxon.switch_in_progress = false;
-		mutex_unlock(&priv->mutex);
-	}
 }
 
 #ifdef CONFIG_IWLWIFI_DEBUG
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.h b/drivers/net/wireless/iwlwifi/iwl-core.h
index a87b54f..36a5097 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -559,6 +559,7 @@ void iwlcore_free_geos(struct iwl_priv *priv);
 #define STATUS_POWER_PMI	16
 #define STATUS_FW_ERROR		17
 #define STATUS_DEVICE_ENABLED	18
+#define STATUS_CHANNEL_SWITCH_PENDING 19
 
 
 static inline int iwl_is_ready(struct iwl_priv *priv)
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 22a6e3e..c8de236 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -982,17 +982,6 @@ struct traffic_stats {
 };
 
 /*
- * iwl_switch_rxon: "channel switch" structure
- *
- * @ switch_in_progress: channel switch in progress
- * @ channel: new channel
- */
-struct iwl_switch_rxon {
-	bool switch_in_progress;
-	__le16 channel;
-};
-
-/*
  * schedule the timer to wake up every UCODE_TRACE_PERIOD milliseconds
  * to perform continuous uCode event logging operation if enabled
  */
@@ -1287,7 +1276,7 @@ struct iwl_priv {
 
 	struct iwl_rxon_context contexts[NUM_IWL_RXON_CTX];
 
-	struct iwl_switch_rxon switch_rxon;
+	__le16 switch_channel;
 
 	struct {
 		u32 error_event_table;
diff --git a/drivers/net/wireless/iwlwifi/iwl-rx.c b/drivers/net/wireless/iwlwifi/iwl-rx.c
index 0053e9e..b774517 100644
--- a/drivers/net/wireless/iwlwifi/iwl-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-rx.c
@@ -250,19 +250,19 @@ static void iwl_rx_csa(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb)
 	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
 	struct iwl_rxon_cmd *rxon = (void *)&ctx->active;
 
-	if (priv->switch_rxon.switch_in_progress) {
-		if (!le32_to_cpu(csa->status) &&
-		    (csa->channel == priv->switch_rxon.channel)) {
-			rxon->channel = csa->channel;
-			ctx->staging.channel = csa->channel;
-			IWL_DEBUG_11H(priv, "CSA notif: channel %d\n",
-			      le16_to_cpu(csa->channel));
-			iwl_chswitch_done(priv, true);
-		} else {
-			IWL_ERR(priv, "CSA notif (fail) : channel %d\n",
+	if (!test_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status))
+		return;
+
+	if (!le32_to_cpu(csa->status) && csa->channel == priv->switch_channel) {
+		rxon->channel = csa->channel;
+		ctx->staging.channel = csa->channel;
+		IWL_DEBUG_11H(priv, "CSA notif: channel %d\n",
 			      le16_to_cpu(csa->channel));
-			iwl_chswitch_done(priv, false);
-		}
+		iwl_chswitch_done(priv, true);
+	} else {
+		IWL_ERR(priv, "CSA notif (fail) : channel %d\n",
+			le16_to_cpu(csa->channel));
+		iwl_chswitch_done(priv, false);
 	}
 }
 
-- 
1.7.1

[PATCH 2/2] iwlagn: refactor iwlagn_mac_channel_switch

[Stanislaw Gruszka]

Use less indentions and remove uneeded irq-save flags.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
---
 drivers/net/wireless/iwlwifi/iwl-agn.c |  106 ++++++++++++++++----------------
 1 files changed, 52 insertions(+), 54 deletions(-)

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 1a143b2..df72cef 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2833,7 +2833,6 @@ static void iwlagn_mac_channel_switch(struct ieee80211_hw *hw,
 	 */
 	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
 	u16 ch;
-	unsigned long flags = 0;
 
 	IWL_DEBUG_MAC80211(priv, "enter\n");
 
@@ -2850,65 +2849,64 @@ static void iwlagn_mac_channel_switch(struct ieee80211_hw *hw,
 	if (!iwl_is_associated_ctx(ctx))
 		goto out;
 
-	if (priv->cfg->ops->lib->set_channel_switch) {
+	if (!priv->cfg->ops->lib->set_channel_switch)
+		goto out;
 
-		ch = channel->hw_value;
-		if (le16_to_cpu(ctx->active.channel) != ch) {
-			ch_info = iwl_get_channel_info(priv,
-						       channel->band,
-						       ch);
-			if (!is_channel_valid(ch_info)) {
-				IWL_DEBUG_MAC80211(priv, "invalid channel\n");
-				goto out;
-			}
-			spin_lock_irqsave(&priv->lock, flags);
-
-			priv->current_ht_config.smps = conf->smps_mode;
-
-			/* Configure HT40 channels */
-			ctx->ht.enabled = conf_is_ht(conf);
-			if (ctx->ht.enabled) {
-				if (conf_is_ht40_minus(conf)) {
-					ctx->ht.extension_chan_offset =
-						IEEE80211_HT_PARAM_CHA_SEC_BELOW;
-					ctx->ht.is_40mhz = true;
-				} else if (conf_is_ht40_plus(conf)) {
-					ctx->ht.extension_chan_offset =
-						IEEE80211_HT_PARAM_CHA_SEC_ABOVE;
-					ctx->ht.is_40mhz = true;
-				} else {
-					ctx->ht.extension_chan_offset =
-						IEEE80211_HT_PARAM_CHA_SEC_NONE;
-					ctx->ht.is_40mhz = false;
-				}
-			} else
-				ctx->ht.is_40mhz = false;
+	ch = channel->hw_value;
+	if (le16_to_cpu(ctx->active.channel) == ch)
+		goto out;
+
+	ch_info = iwl_get_channel_info(priv, channel->band, ch);
+	if (!is_channel_valid(ch_info)) {
+		IWL_DEBUG_MAC80211(priv, "invalid channel\n");
+		goto out;
+	}
 
-			if ((le16_to_cpu(ctx->staging.channel) != ch))
-				ctx->staging.flags = 0;
+	spin_lock_irq(&priv->lock);
 
-			iwl_set_rxon_channel(priv, channel, ctx);
-			iwl_set_rxon_ht(priv, ht_conf);
-			iwl_set_flags_for_band(priv, ctx, channel->band,
-					       ctx->vif);
-			spin_unlock_irqrestore(&priv->lock, flags);
+	priv->current_ht_config.smps = conf->smps_mode;
 
-			iwl_set_rate(priv);
-			/*
-			 * at this point, staging_rxon has the
-			 * configuration for channel switch
-			 */
-			set_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status);
-			priv->switch_channel = cpu_to_le16(ch);
-			if (priv->cfg->ops->lib->set_channel_switch(priv,
-								    ch_switch)) {
-				clear_bit(STATUS_CHANNEL_SWITCH_PENDING,
-					  &priv->status);
-				priv->switch_channel = 0;
-				ieee80211_chswitch_done(ctx->vif, false);
-			}
+	/* Configure HT40 channels */
+	ctx->ht.enabled = conf_is_ht(conf);
+	if (ctx->ht.enabled) {
+		if (conf_is_ht40_minus(conf)) {
+			ctx->ht.extension_chan_offset =
+				IEEE80211_HT_PARAM_CHA_SEC_BELOW;
+			ctx->ht.is_40mhz = true;
+		} else if (conf_is_ht40_plus(conf)) {
+			ctx->ht.extension_chan_offset =
+				IEEE80211_HT_PARAM_CHA_SEC_ABOVE;
+			ctx->ht.is_40mhz = true;
+		} else {
+			ctx->ht.extension_chan_offset =
+				IEEE80211_HT_PARAM_CHA_SEC_NONE;
+			ctx->ht.is_40mhz = false;
 		}
+	} else
+		ctx->ht.is_40mhz = false;
+
+	if ((le16_to_cpu(ctx->staging.channel) != ch))
+		ctx->staging.flags = 0;
+
+	iwl_set_rxon_channel(priv, channel, ctx);
+	iwl_set_rxon_ht(priv, ht_conf);
+	iwl_set_flags_for_band(priv, ctx, channel->band, ctx->vif);
+
+	spin_unlock_irq(&priv->lock);
+
+	iwl_set_rate(priv);
+	/*
+	 * at this point, staging_rxon has the
+	 * configuration for channel switch
+	 */
+	set_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status);
+	priv->switch_channel = cpu_to_le16(ch);
+	if (priv->cfg->ops->lib->set_channel_switch(priv, ch_switch)) {
+		clear_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status);
+		priv->switch_channel = 0;
+		ieee80211_chswitch_done(ctx->vif, false);
 	}
+
 out:
 	mutex_unlock(&priv->mutex);
 	IWL_DEBUG_MAC80211(priv, "leave\n");
-- 
1.7.1

[PATCH 1/2 v2] iwlagn: fix channel switch locking

[Stanislaw Gruszka]

We use priv->mutex to avoid race conditions between iwl_chswitch_done()
and iwlagn_mac_channel_switch(), when marking channel switch in
progress. But iwl_chswitch_done() can be called in atomic context
from iwl_rx_csa() or with mutex already taken from iwlagn_commit_rxon().

These bugs were introduced by:

commit 79d07325502e73508f917475bc1617b60979dd94
Author: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Date:   Thu May 6 08:54:11 2010 -0700

    iwlwifi: support channel switch offload in driver

To fix remove mutex from iwl_chswitch_done() and use atomic bitops for
marking channel switch pending.

Also remove iwl2030_hw_channel_switch() since 2000 series adapters are
2.4GHz only devices.

Cc: stable@kernel.org # 2.6.36+
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
---
 drivers/net/wireless/iwlwifi/iwl-2000.c     |   74 ---------------------------
 drivers/net/wireless/iwlwifi/iwl-5000.c     |    2 -
 drivers/net/wireless/iwlwifi/iwl-6000.c     |    2 -
 drivers/net/wireless/iwlwifi/iwl-agn-rxon.c |    6 +-
 drivers/net/wireless/iwlwifi/iwl-agn.c      |   19 ++++---
 drivers/net/wireless/iwlwifi/iwl-core.c     |    6 +--
 drivers/net/wireless/iwlwifi/iwl-core.h     |    1 +
 drivers/net/wireless/iwlwifi/iwl-dev.h      |   13 +----
 drivers/net/wireless/iwlwifi/iwl-rx.c       |   24 ++++----
 9 files changed, 28 insertions(+), 119 deletions(-)

diff --git a/drivers/net/wireless/iwlwifi/iwl-2000.c b/drivers/net/wireless/iwlwifi/iwl-2000.c
index a37c41b..5484ab7 100644
--- a/drivers/net/wireless/iwlwifi/iwl-2000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-2000.c
@@ -177,79 +177,6 @@ static int iwl2000_hw_set_hw_params(struct iwl_priv *priv)
 	return 0;
 }
 
-static int iwl2030_hw_channel_switch(struct iwl_priv *priv,
-                                    struct ieee80211_channel_switch *ch_switch)
-{
-	/*
-	 * MULTI-FIXME
-	 * See iwl_mac_channel_switch.
-	 */
-	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
-	struct iwl6000_channel_switch_cmd cmd;
-	const struct iwl_channel_info *ch_info;
-	u32 switch_time_in_usec, ucode_switch_time;
-	u16 ch;
-	u32 tsf_low;
-	u8 switch_count;
-	u16 beacon_interval = le16_to_cpu(ctx->timing.beacon_interval);
-	struct ieee80211_vif *vif = ctx->vif;
-	struct iwl_host_cmd hcmd = {
-		.id = REPLY_CHANNEL_SWITCH,
-		.len = { sizeof(cmd), },
-		.flags = CMD_SYNC,
-		.data = { &cmd, },
-	};
-
-	cmd.band = priv->band == IEEE80211_BAND_2GHZ;
-	ch = ch_switch->channel->hw_value;
-	IWL_DEBUG_11H(priv, "channel switch from %u to %u\n",
-		ctx->active.channel, ch);
-	cmd.channel = cpu_to_le16(ch);
-	cmd.rxon_flags = ctx->staging.flags;
-	cmd.rxon_filter_flags = ctx->staging.filter_flags;
-	switch_count = ch_switch->count;
-	tsf_low = ch_switch->timestamp & 0x0ffffffff;
-	/*
-	 * calculate the ucode channel switch time
-	 * adding TSF as one of the factor for when to switch
-	 */
-	if ((priv->ucode_beacon_time > tsf_low) && beacon_interval) {
-		if (switch_count > ((priv->ucode_beacon_time - tsf_low) /
-		    beacon_interval)) {
-			switch_count -= (priv->ucode_beacon_time -
-				tsf_low) / beacon_interval;
-		} else
-			switch_count = 0;
-	}
-	if (switch_count <= 1)
-		cmd.switch_time = cpu_to_le32(priv->ucode_beacon_time);
-	else {
-		switch_time_in_usec =
-			vif->bss_conf.beacon_int * switch_count * TIME_UNIT;
-		ucode_switch_time = iwl_usecs_to_beacons(priv,
-						switch_time_in_usec,
-						beacon_interval);
-		cmd.switch_time = iwl_add_beacon_time(priv,
-						priv->ucode_beacon_time,
-						ucode_switch_time,
-						beacon_interval);
-	}
-	IWL_DEBUG_11H(priv, "uCode time for the switch is 0x%x\n",
-		      cmd.switch_time);
-	ch_info = iwl_get_channel_info(priv, priv->band, ch);
-	if (ch_info)
-		cmd.expect_beacon = is_channel_radar(ch_info);
-	else {
-		IWL_ERR(priv, "invalid channel switch from %u to %u\n",
-			ctx->active.channel, ch);
-		return -EFAULT;
-	}
-	priv->switch_rxon.channel = cmd.channel;
-	priv->switch_rxon.switch_in_progress = true;
-
-	return iwl_send_cmd_sync(priv, &hcmd);
-}
-
 static struct iwl_lib_ops iwl2000_lib = {
 	.set_hw_params = iwl2000_hw_set_hw_params,
 	.rx_handler_setup = iwlagn_rx_handler_setup,
@@ -257,7 +184,6 @@ static struct iwl_lib_ops iwl2000_lib = {
 	.cancel_deferred_work = iwlagn_bt_cancel_deferred_work,
 	.is_valid_rtc_data_addr = iwlagn_hw_valid_rtc_data_addr,
 	.update_chain_flags = iwl_update_chain_flags,
-	.set_channel_switch = iwl2030_hw_channel_switch,
 	.apm_ops = {
 		.init = iwl_apm_init,
 		.config = iwl2000_nic_config,
diff --git a/drivers/net/wireless/iwlwifi/iwl-5000.c b/drivers/net/wireless/iwlwifi/iwl-5000.c
index a8dbbd0..32028b1 100644
--- a/drivers/net/wireless/iwlwifi/iwl-5000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-5000.c
@@ -331,8 +331,6 @@ static int iwl5000_hw_channel_switch(struct iwl_priv *priv,
 			ctx->active.channel, ch);
 		return -EFAULT;
 	}
-	priv->switch_rxon.channel = cmd.channel;
-	priv->switch_rxon.switch_in_progress = true;
 
 	return iwl_send_cmd_sync(priv, &hcmd);
 }
diff --git a/drivers/net/wireless/iwlwifi/iwl-6000.c b/drivers/net/wireless/iwlwifi/iwl-6000.c
index 0e127a7..6e5ce44 100644
--- a/drivers/net/wireless/iwlwifi/iwl-6000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-6000.c
@@ -270,8 +270,6 @@ static int iwl6000_hw_channel_switch(struct iwl_priv *priv,
 			ctx->active.channel, ch);
 		return -EFAULT;
 	}
-	priv->switch_rxon.channel = cmd.channel;
-	priv->switch_rxon.switch_in_progress = true;
 
 	return iwl_send_cmd_sync(priv, &hcmd);
 }
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c b/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
index afb2f20..c263638 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
@@ -370,10 +370,10 @@ int iwlagn_commit_rxon(struct iwl_priv *priv, struct iwl_rxon_context *ctx)
 	 * receive commit_rxon request
 	 * abort any previous channel switch if still in process
 	 */
-	if (priv->switch_rxon.switch_in_progress &&
-	    (priv->switch_rxon.channel != ctx->staging.channel)) {
+	if (test_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status) &&
+	    (priv->switch_channel != ctx->staging.channel)) {
 		IWL_DEBUG_11H(priv, "abort channel switch on %d\n",
-		      le16_to_cpu(priv->switch_rxon.channel));
+			      le16_to_cpu(priv->switch_channel));
 		iwl_chswitch_done(priv, false);
 	}
 
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 88fe755..4239582 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2926,16 +2926,13 @@ static void iwlagn_mac_channel_switch(struct ieee80211_hw *hw,
 		goto out;
 
 	if (test_bit(STATUS_EXIT_PENDING, &priv->status) ||
-	    test_bit(STATUS_SCANNING, &priv->status))
+	    test_bit(STATUS_SCANNING, &priv->status) ||
+	    test_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status))
 		goto out;
 
 	if (!iwl_is_associated_ctx(ctx))
 		goto out;
 
-	/* channel switch in progress */
-	if (priv->switch_rxon.switch_in_progress == true)
-		goto out;
-
 	if (priv->cfg->ops->lib->set_channel_switch) {
 
 		ch = channel->hw_value;
@@ -2984,15 +2981,19 @@ static void iwlagn_mac_channel_switch(struct ieee80211_hw *hw,
 			 * at this point, staging_rxon has the
 			 * configuration for channel switch
 			 */
+			set_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status);
+			priv->switch_channel = cpu_to_le16(ch);
 			if (priv->cfg->ops->lib->set_channel_switch(priv,
-								    ch_switch))
-				priv->switch_rxon.switch_in_progress = false;
+								    ch_switch)) {
+				clear_bit(STATUS_CHANNEL_SWITCH_PENDING,
+					  &priv->status);
+				priv->switch_channel = 0;
+				ieee80211_chswitch_done(ctx->vif, false);
+			}
 		}
 	}
 out:
 	mutex_unlock(&priv->mutex);
-	if (!priv->switch_rxon.switch_in_progress)
-		ieee80211_chswitch_done(ctx->vif, false);
 	IWL_DEBUG_MAC80211(priv, "leave\n");
 }
 
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c b/drivers/net/wireless/iwlwifi/iwl-core.c
index 52e9413..70e6fd1 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.c
+++ b/drivers/net/wireless/iwlwifi/iwl-core.c
@@ -843,12 +843,8 @@ void iwl_chswitch_done(struct iwl_priv *priv, bool is_success)
 	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 		return;
 
-	if (priv->switch_rxon.switch_in_progress) {
+	if (test_and_clear_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status))
 		ieee80211_chswitch_done(ctx->vif, is_success);
-		mutex_lock(&priv->mutex);
-		priv->switch_rxon.switch_in_progress = false;
-		mutex_unlock(&priv->mutex);
-	}
 }
 
 #ifdef CONFIG_IWLWIFI_DEBUG
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.h b/drivers/net/wireless/iwlwifi/iwl-core.h
index a87b54f..36a5097 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -559,6 +559,7 @@ void iwlcore_free_geos(struct iwl_priv *priv);
 #define STATUS_POWER_PMI	16
 #define STATUS_FW_ERROR		17
 #define STATUS_DEVICE_ENABLED	18
+#define STATUS_CHANNEL_SWITCH_PENDING 19
 
 
 static inline int iwl_is_ready(struct iwl_priv *priv)
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 22a6e3e..c8de236 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -982,17 +982,6 @@ struct traffic_stats {
 };
 
 /*
- * iwl_switch_rxon: "channel switch" structure
- *
- * @ switch_in_progress: channel switch in progress
- * @ channel: new channel
- */
-struct iwl_switch_rxon {
-	bool switch_in_progress;
-	__le16 channel;
-};
-
-/*
  * schedule the timer to wake up every UCODE_TRACE_PERIOD milliseconds
  * to perform continuous uCode event logging operation if enabled
  */
@@ -1287,7 +1276,7 @@ struct iwl_priv {
 
 	struct iwl_rxon_context contexts[NUM_IWL_RXON_CTX];
 
-	struct iwl_switch_rxon switch_rxon;
+	__le16 switch_channel;
 
 	struct {
 		u32 error_event_table;
diff --git a/drivers/net/wireless/iwlwifi/iwl-rx.c b/drivers/net/wireless/iwlwifi/iwl-rx.c
index 0053e9e..b774517 100644
--- a/drivers/net/wireless/iwlwifi/iwl-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-rx.c
@@ -250,19 +250,19 @@ static void iwl_rx_csa(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb)
 	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
 	struct iwl_rxon_cmd *rxon = (void *)&ctx->active;
 
-	if (priv->switch_rxon.switch_in_progress) {
-		if (!le32_to_cpu(csa->status) &&
-		    (csa->channel == priv->switch_rxon.channel)) {
-			rxon->channel = csa->channel;
-			ctx->staging.channel = csa->channel;
-			IWL_DEBUG_11H(priv, "CSA notif: channel %d\n",
-			      le16_to_cpu(csa->channel));
-			iwl_chswitch_done(priv, true);
-		} else {
-			IWL_ERR(priv, "CSA notif (fail) : channel %d\n",
+	if (!test_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status))
+		return;
+
+	if (!le32_to_cpu(csa->status) && csa->channel == priv->switch_channel) {
+		rxon->channel = csa->channel;
+		ctx->staging.channel = csa->channel;
+		IWL_DEBUG_11H(priv, "CSA notif: channel %d\n",
 			      le16_to_cpu(csa->channel));
-			iwl_chswitch_done(priv, false);
-		}
+		iwl_chswitch_done(priv, true);
+	} else {
+		IWL_ERR(priv, "CSA notif (fail) : channel %d\n",
+			le16_to_cpu(csa->channel));
+		iwl_chswitch_done(priv, false);
 	}
 }
 
-- 
1.7.1

Re: [PATCH 1/2 v2] iwlagn: fix channel switch locking

[wwguy]

On Thu, 2011-06-02 at 09:17 -0700, Stanislaw Gruszka wrote:
> We use priv->mutex to avoid race conditions between iwl_chswitch_done()
> and iwlagn_mac_channel_switch(), when marking channel switch in
> progress. But iwl_chswitch_done() can be called in atomic context
> from iwl_rx_csa() or with mutex already taken from iwlagn_commit_rxon().
> 
> These bugs were introduced by:
> 
> commit 79d07325502e73508f917475bc1617b60979dd94
> Author: Wey-Yi Guy <wey-yi.w.guy@intel.com>
> Date:   Thu May 6 08:54:11 2010 -0700
> 
>     iwlwifi: support channel switch offload in driver
> 
> To fix remove mutex from iwl_chswitch_done() and use atomic bitops for
> marking channel switch pending.
> 
> Also remove iwl2030_hw_channel_switch() since 2000 series adapters are
> 2.4GHz only devices.
> 
> Cc: stable@kernel.org # 2.6.36+
> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
> ---