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, 12 insertions, 12 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-rx.c b/drivers/net/wireless/iwlwifi/iwl-rx.c
index 0053e9ea9021..b774517aa9fa 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);
         }
 }