idpf: fix netdev Tx queue stop/wake

netif_txq_maybe_stop() returns -1, 0, or 1, while
idpf_tx_maybe_stop_common() says it returns 0 or -EBUSY. As a result,
there sometimes are Tx queue timeout warnings despite that the queue
is empty or there is at least enough space to restart it.
Make idpf_tx_maybe_stop_common() inline and returning true or false,
handling the return of netif_txq_maybe_stop() properly. Use a correct
goto in idpf_tx_maybe_stop_splitq() to avoid stopping the queue or
incrementing the stops counter twice.

Fixes: 6818c4d ("idpf: add splitq start_xmit")
Fixes: a5ab9ee ("idpf: add singleq start_xmit and napi poll")
Cc: [email protected] # 6.7+
Signed-off-by: Michal Kubiak <[email protected]>
Reviewed-by: Przemek Kitszel <[email protected]>
Signed-off-by: Alexander Lobakin <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

Author: michalQb

drivers/net/ethernet/intel/idpf/idpf_singleq_txrx.c

@@ -375,6 +375,10 @@ netdev_tx_t idpf_tx_singleq_frame(struct sk_buff *skb,
 				      IDPF_TX_DESCS_FOR_CTX)) {
 		idpf_tx_buf_hw_update(tx_q, tx_q->next_to_use, false);
 
+		u64_stats_update_begin(&tx_q->stats_sync);
+		u64_stats_inc(&tx_q->q_stats.q_busy);
+		u64_stats_update_end(&tx_q->stats_sync);
+
 		return NETDEV_TX_BUSY;
 	}
 

drivers/net/ethernet/intel/idpf/idpf_txrx.c

@@ -2132,29 +2132,6 @@ void idpf_tx_splitq_build_flow_desc(union idpf_tx_flex_desc *desc,
 	desc->flow.qw1.compl_tag = cpu_to_le16(params->compl_tag);
 }
 
-/**
- * idpf_tx_maybe_stop_common - 1st level check for common Tx stop conditions
- * @tx_q: the queue to be checked
- * @size: number of descriptors we want to assure is available
- *
- * Returns 0 if stop is not needed
- */
-int idpf_tx_maybe_stop_common(struct idpf_tx_queue *tx_q, unsigned int size)
-{
-	struct netdev_queue *nq;
-
-	if (likely(IDPF_DESC_UNUSED(tx_q) >= size))
-		return 0;
-
-	u64_stats_update_begin(&tx_q->stats_sync);
-	u64_stats_inc(&tx_q->q_stats.q_busy);
-	u64_stats_update_end(&tx_q->stats_sync);
-
-	nq = netdev_get_tx_queue(tx_q->netdev, tx_q->idx);
-
-	return netif_txq_maybe_stop(nq, IDPF_DESC_UNUSED(tx_q), size, size);
-}
-
 /**
  * idpf_tx_maybe_stop_splitq - 1st level check for Tx splitq stop conditions
  * @tx_q: the queue to be checked
@@ -2166,7 +2143,7 @@ static int idpf_tx_maybe_stop_splitq(struct idpf_tx_queue *tx_q,
 				     unsigned int descs_needed)
 {
 	if (idpf_tx_maybe_stop_common(tx_q, descs_needed))
-		goto splitq_stop;
+		goto out;
 
 	/* If there are too many outstanding completions expected on the
 	 * completion queue, stop the TX queue to give the device some time to
@@ -2185,10 +2162,12 @@ static int idpf_tx_maybe_stop_splitq(struct idpf_tx_queue *tx_q,
 	return 0;
 
 splitq_stop:
+	netif_stop_subqueue(tx_q->netdev, tx_q->idx);
+
+out:
 	u64_stats_update_begin(&tx_q->stats_sync);
 	u64_stats_inc(&tx_q->q_stats.q_busy);
 	u64_stats_update_end(&tx_q->stats_sync);
-	netif_stop_subqueue(tx_q->netdev, tx_q->idx);
 
 	return -EBUSY;
 }
@@ -2211,7 +2190,11 @@ void idpf_tx_buf_hw_update(struct idpf_tx_queue *tx_q, u32 val,
 	nq = netdev_get_tx_queue(tx_q->netdev, tx_q->idx);
 	tx_q->next_to_use = val;
 
-	idpf_tx_maybe_stop_common(tx_q, IDPF_TX_DESC_NEEDED);
+	if (idpf_tx_maybe_stop_common(tx_q, IDPF_TX_DESC_NEEDED)) {
+		u64_stats_update_begin(&tx_q->stats_sync);
+		u64_stats_inc(&tx_q->q_stats.q_busy);
+		u64_stats_update_end(&tx_q->stats_sync);
+	}
 
 	/* Force memory writes to complete before letting h/w
 	 * know there are new descriptors to fetch.  (Only

drivers/net/ethernet/intel/idpf/idpf_txrx.h

@@ -1018,7 +1018,6 @@ void idpf_tx_dma_map_error(struct idpf_tx_queue *txq, struct sk_buff *skb,
 			   struct idpf_tx_buf *first, u16 ring_idx);
 unsigned int idpf_tx_desc_count_required(struct idpf_tx_queue *txq,
 					 struct sk_buff *skb);
-int idpf_tx_maybe_stop_common(struct idpf_tx_queue *tx_q, unsigned int size);
 void idpf_tx_timeout(struct net_device *netdev, unsigned int txqueue);
 netdev_tx_t idpf_tx_singleq_frame(struct sk_buff *skb,
 				  struct idpf_tx_queue *tx_q);
@@ -1027,4 +1026,12 @@ bool idpf_rx_singleq_buf_hw_alloc_all(struct idpf_rx_queue *rxq,
 				      u16 cleaned_count);
 int idpf_tso(struct sk_buff *skb, struct idpf_tx_offload_params *off);
 
+static inline bool idpf_tx_maybe_stop_common(struct idpf_tx_queue *tx_q,
+					     u32 needed)
+{
+	return !netif_subqueue_maybe_stop(tx_q->netdev, tx_q->idx,
+					  IDPF_DESC_UNUSED(tx_q),
+					  needed, needed);
+}
+
 #endif /* !_IDPF_TXRX_H_ */