iwlwifi: virtualize op_mode's free skb

This handler allows the transport layer to free an skb from the
op_mode. This can happen when the driver is stopped while Tx
packets are pending in the transport layer.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

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

@@ -1170,6 +1170,8 @@ static struct iwl_op_mode *iwl_op_mode_dvm_start(struct iwl_trans *trans)
 	priv->shrd = trans->shrd;
 	priv->shrd->priv = priv;
 
+	iwl_trans_configure(trans(priv), op_mode);
+
 	/* At this point both hw and priv are allocated. */
 
 	SET_IEEE80211_DEV(priv->hw, trans(priv)->dev);
@@ -1383,6 +1385,7 @@ static void iwl_op_mode_dvm_stop(struct iwl_op_mode *op_mode)
 const struct iwl_op_mode_ops iwl_dvm_ops = {
 	.start = iwl_op_mode_dvm_start,
 	.stop = iwl_op_mode_dvm_stop,
+	.free_skb = iwl_free_skb,
 };
 
 /*****************************************************************************

drivers/net/wireless/iwlwifi/iwl-agn.h

@@ -80,6 +80,7 @@ static inline void iwl_set_calib_hdr(struct iwl_calib_hdr *hdr, u8 cmd)
 void iwl_down(struct iwl_priv *priv);
 void iwl_cancel_deferred_work(struct iwl_priv *priv);
 void iwlagn_prepare_restart(struct iwl_priv *priv);
+void iwl_free_skb(struct iwl_op_mode *op_mode, struct sk_buff *skb);
 
 /* MAC80211 */
 struct ieee80211_hw *iwl_alloc_all(void);

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

@@ -41,6 +41,7 @@
 #include "iwl-shared.h"
 #include "iwl-agn.h"
 #include "iwl-trans.h"
+#include "iwl-wifi.h"
 
 const u8 iwl_bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
 
@@ -1464,8 +1465,9 @@ void iwl_nic_config(struct iwl_priv *priv)
 	cfg(priv)->lib->nic_config(priv);
 }
 
-void iwl_free_skb(struct iwl_priv *priv, struct sk_buff *skb)
+void iwl_free_skb(struct iwl_op_mode *op_mode, struct sk_buff *skb)
 {
+	struct iwl_priv *priv = IWL_OP_MODE_GET_DVM(op_mode);
 	struct ieee80211_tx_info *info;
 
 	info = IEEE80211_SKB_CB(skb);

drivers/net/wireless/iwlwifi/iwl-op-mode.h

@@ -65,6 +65,7 @@
 
 struct iwl_op_mode;
 struct iwl_trans;
+struct sk_buff;
 
 /**
  * struct iwl_op_mode_ops - op_mode specific operations
@@ -75,10 +76,15 @@ struct iwl_trans;
  *	May sleep
  * @stop: stop the op_mode
  *	May sleep
+ * @free_skb: allows the transport layer to free skbs that haven't been
+ *	reclaimed by the op_mode. This can happen when the driver is freed and
+ *	there are Tx packets pending in the transport layer.
+ *	Must be atomic
  */
 struct iwl_op_mode_ops {
 	struct iwl_op_mode *(*start)(struct iwl_trans *trans);
 	void (*stop)(struct iwl_op_mode *op_mode);
+	void (*free_skb)(struct iwl_op_mode *op_mode, struct sk_buff *skb);
 };
 
 /**
@@ -100,6 +106,12 @@ static inline void iwl_op_mode_stop(struct iwl_op_mode *op_mode)
 	op_mode->ops->stop(op_mode);
 }
 
+static inline void iwl_op_mode_free_skb(struct iwl_op_mode *op_mode,
+					struct sk_buff *skb)
+{
+	op_mode->ops->free_skb(op_mode, skb);
+}
+
 /*****************************************************
 * Op mode layers implementations
 ******************************************************/

drivers/net/wireless/iwlwifi/iwl-shared.h

@@ -540,7 +540,6 @@ int __must_check iwl_rx_dispatch(struct iwl_priv *priv,
 int iwlagn_hw_valid_rtc_data_addr(u32 addr);
 void iwl_set_hw_rfkill_state(struct iwl_priv *priv, bool state);
 void iwl_nic_config(struct iwl_priv *priv);
-void iwl_free_skb(struct iwl_priv *priv, struct sk_buff *skb);
 void iwlagn_fw_error(struct iwl_priv *priv, bool ondemand);
 const char *get_cmd_string(u8 cmd);
 bool iwl_check_for_ct_kill(struct iwl_priv *priv);

drivers/net/wireless/iwlwifi/iwl-trans-pcie-tx.c

@@ -35,6 +35,7 @@
 #include "iwl-prph.h"
 #include "iwl-io.h"
 #include "iwl-agn-hw.h"
+#include "iwl-op-mode.h"
 #include "iwl-trans-pcie-int.h"
 
 #define IWL_TX_CRC_SIZE 4
@@ -229,7 +230,7 @@ void iwlagn_txq_free_tfd(struct iwl_trans *trans, struct iwl_tx_queue *txq,
 		 * freed and that the queue is not empty - free the skb
 		 */
 		if (skb) {
-			iwl_free_skb(priv(trans), skb);
+			iwl_op_mode_free_skb(trans->op_mode, skb);
 			txq->skbs[index] = NULL;
 		}
 	}

drivers/net/wireless/iwlwifi/iwl-trans.h

@@ -114,6 +114,7 @@
 
 struct iwl_priv;
 struct iwl_shared;
+struct iwl_op_mode;
 
 /**
  * DOC: Host command section
@@ -312,6 +313,7 @@ enum iwl_trans_state {
  * struct iwl_trans - transport common data
  *
  * @ops - pointer to iwl_trans_ops
+ * @op_mode - pointer to the op_mode
  * @shrd - pointer to iwl_shared which holds shared data from the upper layer
  * @hcmd_lock: protects HCMD
  * @reg_lock - protect hw register access
@@ -327,6 +329,7 @@ enum iwl_trans_state {
  */
 struct iwl_trans {
 	const struct iwl_trans_ops *ops;
+	struct iwl_op_mode *op_mode;
 	struct iwl_shared *shrd;
 	enum iwl_trans_state state;
 	spinlock_t hcmd_lock;
@@ -350,6 +353,16 @@ struct iwl_trans {
 	char trans_specific[0] __aligned(sizeof(void *));
 };
 
+static inline void iwl_trans_configure(struct iwl_trans *trans,
+				       struct iwl_op_mode *op_mode)
+{
+	/*
+	 * only set the op_mode for the moment. Later on, this function will do
+	 * more
+	 */
+	trans->op_mode = op_mode;
+}
+
 static inline int iwl_trans_start_hw(struct iwl_trans *trans)
 {
 	might_sleep();