iwlagn: fix channel switch locking

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>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/iwlwifi/iwl-2000.c b/drivers/net/wireless/iwlwifi/iwl-2000.c
index 86feec8..2282279 100644 (file)
--- 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,
@@ -258,7 +185,6 @@ static struct iwl_lib_ops iwl2000_lib = {
        .is_valid_rtc_data_addr = iwlagn_hw_valid_rtc_data_addr,
        .send_tx_power = iwlagn_send_tx_power,
        .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 a70b8cf..5b721c5 100644 (file)
--- 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 fda6fe0..fbe565c 100644 (file)
--- 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 a95ad84..2532c7d 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
@@ -342,10 +342,10 @@ 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 a662adc..8e1942e 100644 (file)
--- 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 4653dea..213c80c 100644 (file)
--- 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 3bb76f6..a54d416 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -560,6 +560,7 @@ 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 (file)
--- 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 (file)
--- 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);
        }
 }