iwlwifi: fix possible priv->mutex deadlock during suspend

This patch moves _cancel_deferred_work out of mutex protection and removes
unnecessary mutex in pci_suspend and pci_resume.

Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl3945-base.c

@@ -6243,8 +6243,6 @@ static void __iwl_down(struct iwl_priv *priv)
 	/* Unblock any waiting calls */
 	wake_up_interruptible_all(&priv->wait_command_queue);
 
-	iwl_cancel_deferred_work(priv);
-
 	/* Wipe out the EXIT_PENDING status bit if we are not actually
 	 * exiting the module */
 	if (!exit_pending)
@@ -6319,6 +6317,8 @@ static void iwl_down(struct iwl_priv *priv)
 	mutex_lock(&priv->mutex);
 	__iwl_down(priv);
 	mutex_unlock(&priv->mutex);
+
+	iwl_cancel_deferred_work(priv);
 }
 
 #define MAX_HW_RESTARTS 5
@@ -8577,10 +8577,9 @@ static void iwl_pci_remove(struct pci_dev *pdev)
 
 	IWL_DEBUG_INFO("*** UNLOAD DRIVER ***\n");
 
-	mutex_lock(&priv->mutex);
 	set_bit(STATUS_EXIT_PENDING, &priv->status);
-	__iwl_down(priv);
-	mutex_unlock(&priv->mutex);
+
+	iwl_down(priv);
 
 	/* Free MAC hash list for ADHOC */
 	for (i = 0; i < IWL_IBSS_MAC_HASH_SIZE; i++) {
@@ -8639,12 +8638,10 @@ static int iwl_pci_suspend(struct pci_dev *pdev, pm_message_t state)
 {
 	struct iwl_priv *priv = pci_get_drvdata(pdev);
 
-	mutex_lock(&priv->mutex);
-
 	set_bit(STATUS_IN_SUSPEND, &priv->status);
 
 	/* Take down the device; powers it off, etc. */
-	__iwl_down(priv);
+	iwl_down(priv);
 
 	if (priv->mac80211_registered)
 		ieee80211_stop_queues(priv->hw);
@@ -8653,8 +8650,6 @@ static int iwl_pci_suspend(struct pci_dev *pdev, pm_message_t state)
 	pci_disable_device(pdev);
 	pci_set_power_state(pdev, PCI_D3hot);
 
-	mutex_unlock(&priv->mutex);
-
 	return 0;
 }
 
@@ -8712,8 +8707,6 @@ static int iwl_pci_resume(struct pci_dev *pdev)
 
 	printk(KERN_INFO "Coming out of suspend...\n");
 
-	mutex_lock(&priv->mutex);
-
 	pci_set_power_state(pdev, PCI_D0);
 	err = pci_enable_device(pdev);
 	pci_restore_state(pdev);
@@ -8727,7 +8720,6 @@ static int iwl_pci_resume(struct pci_dev *pdev)
 	pci_write_config_byte(pdev, 0x41, 0x00);
 
 	iwl_resume(priv);
-	mutex_unlock(&priv->mutex);
 
 	return 0;
 }

drivers/net/wireless/iwlwifi/iwl4965-base.c

@@ -6598,8 +6598,6 @@ static void __iwl_down(struct iwl_priv *priv)
 	/* Unblock any waiting calls */
 	wake_up_interruptible_all(&priv->wait_command_queue);
 
-	iwl_cancel_deferred_work(priv);
-
 	/* Wipe out the EXIT_PENDING status bit if we are not actually
 	 * exiting the module */
 	if (!exit_pending)
@@ -6674,6 +6672,8 @@ static void iwl_down(struct iwl_priv *priv)
 	mutex_lock(&priv->mutex);
 	__iwl_down(priv);
 	mutex_unlock(&priv->mutex);
+
+	iwl_cancel_deferred_work(priv);
 }
 
 #define MAX_HW_RESTARTS 5
@@ -9171,10 +9171,9 @@ static void iwl_pci_remove(struct pci_dev *pdev)
 
 	IWL_DEBUG_INFO("*** UNLOAD DRIVER ***\n");
 
-	mutex_lock(&priv->mutex);
 	set_bit(STATUS_EXIT_PENDING, &priv->status);
-	__iwl_down(priv);
-	mutex_unlock(&priv->mutex);
+
+	iwl_down(priv);
 
 	/* Free MAC hash list for ADHOC */
 	for (i = 0; i < IWL_IBSS_MAC_HASH_SIZE; i++) {
@@ -9233,12 +9232,10 @@ static int iwl_pci_suspend(struct pci_dev *pdev, pm_message_t state)
 {
 	struct iwl_priv *priv = pci_get_drvdata(pdev);
 
-	mutex_lock(&priv->mutex);
-
 	set_bit(STATUS_IN_SUSPEND, &priv->status);
 
 	/* Take down the device; powers it off, etc. */
-	__iwl_down(priv);
+	iwl_down(priv);
 
 	if (priv->mac80211_registered)
 		ieee80211_stop_queues(priv->hw);
@@ -9247,8 +9244,6 @@ static int iwl_pci_suspend(struct pci_dev *pdev, pm_message_t state)
 	pci_disable_device(pdev);
 	pci_set_power_state(pdev, PCI_D3hot);
 
-	mutex_unlock(&priv->mutex);
-
 	return 0;
 }
 
@@ -9306,8 +9301,6 @@ static int iwl_pci_resume(struct pci_dev *pdev)
 
 	printk(KERN_INFO "Coming out of suspend...\n");
 
-	mutex_lock(&priv->mutex);
-
 	pci_set_power_state(pdev, PCI_D0);
 	err = pci_enable_device(pdev);
 	pci_restore_state(pdev);
@@ -9321,7 +9314,6 @@ static int iwl_pci_resume(struct pci_dev *pdev)
 	pci_write_config_byte(pdev, 0x41, 0x00);
 
 	iwl_resume(priv);
-	mutex_unlock(&priv->mutex);
 
 	return 0;
 }