iwlwifi: warn when send tx power settings during scan

Add WARN_ONCE when scanning is pending. Use STATUS_SCAN_HW bit since we
can have scan canceled or completed but STATUS_SCANNING bit still set.

v1 -> v2: replace EIO to EAGAIN

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-3945.c

@@ -1451,6 +1451,10 @@ static int iwl3945_send_tx_power(struct iwl_priv *priv)
 	};
 	u16 chan;
 
+	if (WARN_ONCE(test_bit(STATUS_SCAN_HW, &priv->status),
+		      "TX Power requested while scanning!\n"))
+		return -EAGAIN;
+
 	chan = le16_to_cpu(priv->contexts[IWL_RXON_CTX_BSS].active.channel);
 
 	txpower.band = (priv->band == IEEE80211_BAND_5GHZ) ? 0 : 1;

drivers/net/wireless/iwlwifi/iwl-4965.c

@@ -1377,13 +1377,9 @@ static int iwl4965_send_tx_power(struct iwl_priv *priv)
 	u8 ctrl_chan_high = 0;
 	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
 
-	if (test_bit(STATUS_SCANNING, &priv->status)) {
-		/* If this gets hit a lot, switch it to a BUG() and catch
-		 * the stack trace to find out who is calling this during
-		 * a scan. */
-		IWL_WARN(priv, "TX Power requested while scanning!\n");
+	if (WARN_ONCE(test_bit(STATUS_SCAN_HW, &priv->status),
+		      "TX Power requested while scanning!\n"))
 		return -EAGAIN;
-	}
 
 	band = priv->band == IEEE80211_BAND_2GHZ;
 

drivers/net/wireless/iwlwifi/iwl-agn-lib.c

@@ -496,6 +496,10 @@ int iwlagn_send_tx_power(struct iwl_priv *priv)
 	struct iwlagn_tx_power_dbm_cmd tx_power_cmd;
 	u8 tx_ant_cfg_cmd;
 
+	if (WARN_ONCE(test_bit(STATUS_SCAN_HW, &priv->status),
+		      "TX Power requested while scanning!\n"))
+		return -EAGAIN;
+
 	/* half dBm need to multiply */
 	tx_power_cmd.global_lmt = (s8)(2 * priv->tx_power_user_lmt);