wifi: mwifiex: drop BUG_ON from TX paths

In 'mwifiex_process_sta_txpd()' and 'mwifiex_process_uap_txpd()',
replace 'BUG_ON()' with runtime check, and move all these checks
to 'mwifiex_process_tx()'. This way, both callees may be converted
to 'void', and the caller may be simplified as well.
Suggested-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Acked-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230802160726.85545-5-dmantipov@yandex.ru

drivers/net/wireless/marvell/mwifiex/main.h

@@ -1144,8 +1144,10 @@ int mwifiex_process_uap_event(struct mwifiex_private *);
 void mwifiex_delete_all_station_list(struct mwifiex_private *priv);
 void mwifiex_wmm_del_peer_ra_list(struct mwifiex_private *priv,
 				  const u8 *ra_addr);
-void *mwifiex_process_sta_txpd(struct mwifiex_private *, struct sk_buff *skb);
-void *mwifiex_process_uap_txpd(struct mwifiex_private *, struct sk_buff *skb);
+void mwifiex_process_sta_txpd(struct mwifiex_private *priv,
+			      struct sk_buff *skb);
+void mwifiex_process_uap_txpd(struct mwifiex_private *priv,
+			      struct sk_buff *skb);
 int mwifiex_sta_init_cmd(struct mwifiex_private *, u8 first_sta, bool init);
 int mwifiex_cmd_802_11_scan(struct host_cmd_ds_command *cmd,
 			    struct mwifiex_scan_cmd_config *scan_cfg);

drivers/net/wireless/marvell/mwifiex/sta_tx.c

@@ -29,7 +29,7 @@
  *      - Priority specific Tx control
  *      - Flags
  */
-void *mwifiex_process_sta_txpd(struct mwifiex_private *priv,
+void mwifiex_process_sta_txpd(struct mwifiex_private *priv,
 			      struct sk_buff *skb)
 {
 	struct mwifiex_adapter *adapter = priv->adapter;
@@ -39,14 +39,6 @@ void *mwifiex_process_sta_txpd(struct mwifiex_private *priv,
 	u16 pkt_type, pkt_offset;
 	int hroom = adapter->intf_hdr_len;
 
-	if (!skb->len) {
-		mwifiex_dbg(adapter, ERROR,
-			    "Tx: bad packet length: %d\n", skb->len);
-		return skb->data;
-	}
-
-	BUG_ON(skb_headroom(skb) < MWIFIEX_MIN_DATA_HEADER_LEN);
-
 	pkt_type = mwifiex_is_skb_mgmt_frame(skb) ? PKT_TYPE_MGMT : 0;
 
 	pad = ((uintptr_t)skb->data - (sizeof(*local_tx_pd) + hroom)) &
@@ -108,8 +100,6 @@ void *mwifiex_process_sta_txpd(struct mwifiex_private *priv,
 	if (!local_tx_pd->tx_control)
 		/* TxCtrl set by user or default */
 		local_tx_pd->tx_control = cpu_to_le32(priv->pkt_tx_ctrl);
-
-	return skb->data;
 }
 
 /*

drivers/net/wireless/marvell/mwifiex/txrx.c

@@ -72,13 +72,18 @@ EXPORT_SYMBOL_GPL(mwifiex_handle_rx_packet);
 int mwifiex_process_tx(struct mwifiex_private *priv, struct sk_buff *skb,
 		       struct mwifiex_tx_param *tx_param)
 {
-	int hroom, ret = -1;
+	int hroom, ret;
 	struct mwifiex_adapter *adapter = priv->adapter;
-	u8 *head_ptr;
 	struct txpd *local_tx_pd = NULL;
 	struct mwifiex_sta_node *dest_node;
 	struct ethhdr *hdr = (void *)skb->data;
 
+	if (unlikely(!skb->len ||
+		     skb_headroom(skb) < MWIFIEX_MIN_DATA_HEADER_LEN)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	hroom = adapter->intf_hdr_len;
 
 	if (priv->bss_role == MWIFIEX_BSS_ROLE_UAP) {
@@ -88,20 +93,19 @@ int mwifiex_process_tx(struct mwifiex_private *priv, struct sk_buff *skb,
 			dest_node->stats.tx_packets++;
 		}
 
-		head_ptr = mwifiex_process_uap_txpd(priv, skb);
+		mwifiex_process_uap_txpd(priv, skb);
 	} else {
-		head_ptr = mwifiex_process_sta_txpd(priv, skb);
+		mwifiex_process_sta_txpd(priv, skb);
 	}
 
-	if ((adapter->data_sent || adapter->tx_lock_flag) && head_ptr) {
+	if (adapter->data_sent || adapter->tx_lock_flag) {
 		skb_queue_tail(&adapter->tx_data_q, skb);
 		atomic_inc(&adapter->tx_queued);
 		return 0;
 	}
 
-	if (head_ptr) {
 	if (GET_BSS_ROLE(priv) == MWIFIEX_BSS_ROLE_STA)
-			local_tx_pd = (struct txpd *)(head_ptr + hroom);
+		local_tx_pd = (struct txpd *)(skb->data + hroom);
 	if (adapter->iface_type == MWIFIEX_USB) {
 		ret = adapter->if_ops.host_to_card(adapter,
 						   priv->usb_port,
@@ -111,10 +115,9 @@ int mwifiex_process_tx(struct mwifiex_private *priv, struct sk_buff *skb,
 						   MWIFIEX_TYPE_DATA,
 						   skb, tx_param);
 	}
-	}
 	mwifiex_dbg_dump(adapter, DAT_D, "tx pkt:", skb->data,
 			 min_t(size_t, skb->len, DEBUG_DUMP_DATA_MAX_LEN));
-
+out:
 	switch (ret) {
 	case -ENOSR:
 		mwifiex_dbg(adapter, DATA, "data: -ENOSR is returned\n");
@@ -137,6 +140,11 @@ int mwifiex_process_tx(struct mwifiex_private *priv, struct sk_buff *skb,
 		break;
 	case -EINPROGRESS:
 		break;
+	case -EINVAL:
+		mwifiex_dbg(adapter, ERROR,
+			    "malformed skb (length: %u, headroom: %u)\n",
+			    skb->len, skb_headroom(skb));
+		fallthrough;
 	case 0:
 		mwifiex_write_data_complete(adapter, skb, 0, ret);
 		break;

drivers/net/wireless/marvell/mwifiex/uap_txrx.c

@@ -461,7 +461,7 @@ int mwifiex_process_uap_rx_packet(struct mwifiex_private *priv,
  *      - Priority specific Tx control
  *      - Flags
  */
-void *mwifiex_process_uap_txpd(struct mwifiex_private *priv,
+void mwifiex_process_uap_txpd(struct mwifiex_private *priv,
 			      struct sk_buff *skb)
 {
 	struct mwifiex_adapter *adapter = priv->adapter;
@@ -471,14 +471,6 @@ void *mwifiex_process_uap_txpd(struct mwifiex_private *priv,
 	u16 pkt_type, pkt_offset;
 	int hroom = adapter->intf_hdr_len;
 
-	if (!skb->len) {
-		mwifiex_dbg(adapter, ERROR,
-			    "Tx: bad packet length: %d\n", skb->len);
-		return skb->data;
-	}
-
-	BUG_ON(skb_headroom(skb) < MWIFIEX_MIN_DATA_HEADER_LEN);
-
 	pkt_type = mwifiex_is_skb_mgmt_frame(skb) ? PKT_TYPE_MGMT : 0;
 
 	pad = ((uintptr_t)skb->data - (sizeof(*txpd) + hroom)) &
@@ -526,6 +518,4 @@ void *mwifiex_process_uap_txpd(struct mwifiex_private *priv,
 	if (!txpd->tx_control)
 		/* TxCtrl set by user or default */
 		txpd->tx_control = cpu_to_le32(priv->pkt_tx_ctrl);
-
-	return skb->data;
 }