iwlegacy: fix channel switch locking

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

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

Cc: stable@kernel.org # 2.6.39+
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 3 insertions, 6 deletions

diff --git a/drivers/net/wireless/iwlegacy/iwl-4965.c b/drivers/net/wireless/iwlegacy/iwl-4965.c
index e1b89220c186..facc94e74b07 100644
--- a/drivers/net/wireless/iwlegacy/iwl-4965.c
+++ b/drivers/net/wireless/iwlegacy/iwl-4965.c
@@ -1218,10 +1218,10 @@ static int iwl4965_commit_rxon(struct iwl_priv *priv, struct iwl_rxon_context *c
 	 * 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_legacy_chswitch_done(priv, false);
 	}
 
@@ -1404,9 +1404,6 @@ static int iwl4965_hw_channel_switch(struct iwl_priv *priv,
 		return rc;
 	}
 
-	priv->switch_rxon.channel = cmd.channel;
-	priv->switch_rxon.switch_in_progress = true;
-
 	return iwl_legacy_send_cmd_pdu(priv,
 			 REPLY_CHANNEL_SWITCH, sizeof(cmd), &cmd);
 }