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>

1 files changed, 0 insertions, 74 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-2000.c b/drivers/net/wireless/iwlwifi/iwl-2000.c
index 86feec8..2282279 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,
@@ -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,