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 e1b89220c18..facc94e74b0 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);
 }