net: mana: Drop TX skb on post_work_request failure and unmap resources

Drop TX packets when posting the work request fails and ensure DMA
mappings are always cleaned up.

Signed-off-by: Aditya Garg <[e-mail]>
Reviewed-by: Haiyang Zhang <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/microsoft/mana/gdma_main.c

···
 			      struct gdma_posted_wqe_info *wqe_info)
 {
 	u32 client_oob_size = wqe_req->inline_oob_size;
-	struct gdma_context *gc;
 	u32 sgl_data_size;
 	u32 max_wqe_size;
 	u32 wqe_size;
···
 	if (wqe_size > max_wqe_size)
 		return -EINVAL;
 
-	if (wq->monitor_avl_buf && wqe_size > mana_gd_wq_avail_space(wq)) {
-		gc = wq->gdma_dev->gdma_context;
-		dev_err(gc->dev, "unsuccessful flow control!\n");
+	if (wq->monitor_avl_buf && wqe_size > mana_gd_wq_avail_space(wq))
 		return -ENOSPC;
-	}
 
 	if (wqe_info)
 		wqe_info->wqe_size_in_bu = wqe_size / GDMA_WQE_BU_SIZE;

drivers/net/ethernet/microsoft/mana/mana_en.c

···
 
 	if (err) {
 		(void)skb_dequeue_tail(&txq->pending_skbs);
+		mana_unmap_skb(skb, apc);
 		netdev_warn(ndev, "Failed to post TX OOB: %d\n", err);
-		err = NETDEV_TX_BUSY;
-		goto tx_busy;
+		goto free_sgl_ptr;
 	}
 
 	err = NETDEV_TX_OK;
···
 	tx_stats->bytes += len + ((num_gso_seg - 1) * gso_hs);
 	u64_stats_update_end(&tx_stats->syncp);
 
-tx_busy:
 	if (netif_tx_queue_stopped(net_txq) && mana_can_tx(gdma_sq)) {
 		netif_tx_wake_queue(net_txq);
 		apc->eth_stats.wake_queue++;
···
 	return 0;
 }
 
-static void mana_unmap_skb(struct sk_buff *skb, struct mana_port_context *apc)
+void mana_unmap_skb(struct sk_buff *skb, struct mana_port_context *apc)
 {
 	struct mana_skb_head *ash = (struct mana_skb_head *)skb->head;
 	struct gdma_context *gc = apc->ac->gdma_dev->gdma_context;

include/net/mana/mana.h

···
 void mana_query_phy_stats(struct mana_port_context *apc);
 int mana_pre_alloc_rxbufs(struct mana_port_context *apc, int mtu, int num_queues);
 void mana_pre_dealloc_rxbufs(struct mana_port_context *apc);
+void mana_unmap_skb(struct sk_buff *skb, struct mana_port_context *apc);
 
 extern const struct ethtool_ops mana_ethtool_ops;
 extern struct dentry *mana_debugfs_root;