2 files changed, 107 insertions, 69 deletions

diff --git a/drivers/net/ntb_netdev.c b/drivers/net/ntb_netdev.c
index 3cc316cb7e6b..5f1ee7c05f68 100644
--- a/drivers/net/ntb_netdev.c
+++ b/drivers/net/ntb_netdev.c
@@ -102,6 +102,12 @@ static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data,
 
 	netdev_dbg(ndev, "%s: %d byte payload received\n", __func__, len);
 
+	if (len < 0) {
+		ndev->stats.rx_errors++;
+		ndev->stats.rx_length_errors++;
+		goto enqueue_again;
+	}
+
 	skb_put(skb, len);
 	skb->protocol = eth_type_trans(skb, ndev);
 	skb->ip_summed = CHECKSUM_NONE;
@@ -121,6 +127,7 @@ static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data,
 		return;
 	}
 
+enqueue_again:
 	rc = ntb_transport_rx_enqueue(qp, skb, skb->data, ndev->mtu + ETH_HLEN);
 	if (rc) {
 		dev_kfree_skb(skb);
diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index efe3ad4122f2..98e58c765f2e 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -142,10 +142,11 @@ struct ntb_transport_qp {
 
 	void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
 			   void *data, int len);
+	struct list_head rx_post_q;
 	struct list_head rx_pend_q;
 	struct list_head rx_free_q;
-	spinlock_t ntb_rx_pend_q_lock;
-	spinlock_t ntb_rx_free_q_lock;
+	/* ntb_rx_q_lock: synchronize access to rx_XXXX_q */
+	spinlock_t ntb_rx_q_lock;
 	void *rx_buff;
 	unsigned int rx_index;
 	unsigned int rx_max_entry;
@@ -534,6 +535,27 @@ out:
 	return entry;
 }
 
+static struct ntb_queue_entry *ntb_list_mv(spinlock_t *lock,
+					   struct list_head *list,
+					   struct list_head *to_list)
+{
+	struct ntb_queue_entry *entry;
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
+
+	if (list_empty(list)) {
+		entry = NULL;
+	} else {
+		entry = list_first_entry(list, struct ntb_queue_entry, entry);
+		list_move_tail(&entry->entry, to_list);
+	}
+
+	spin_unlock_irqrestore(lock, flags);
+
+	return entry;
+}
+
 static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
 				     unsigned int qp_num)
 {
@@ -941,10 +963,10 @@ static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
 	INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
 	INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup_work);
 
-	spin_lock_init(&qp->ntb_rx_pend_q_lock);
-	spin_lock_init(&qp->ntb_rx_free_q_lock);
+	spin_lock_init(&qp->ntb_rx_q_lock);
 	spin_lock_init(&qp->ntb_tx_free_q_lock);
 
+	INIT_LIST_HEAD(&qp->rx_post_q);
 	INIT_LIST_HEAD(&qp->rx_pend_q);
 	INIT_LIST_HEAD(&qp->rx_free_q);
 	INIT_LIST_HEAD(&qp->tx_free_q);
@@ -1107,22 +1129,47 @@ static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
 	kfree(nt);
 }
 
-static void ntb_rx_copy_callback(void *data)
+static void ntb_complete_rxc(struct ntb_transport_qp *qp)
 {
-	struct ntb_queue_entry *entry = data;
-	struct ntb_transport_qp *qp = entry->qp;
-	void *cb_data = entry->cb_data;
-	unsigned int len = entry->len;
-	struct ntb_payload_header *hdr = entry->rx_hdr;
+	struct ntb_queue_entry *entry;
+	void *cb_data;
+	unsigned int len;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
+
+	while (!list_empty(&qp->rx_post_q)) {
+		entry = list_first_entry(&qp->rx_post_q,
+					 struct ntb_queue_entry, entry);
+		if (!(entry->flags & DESC_DONE_FLAG))
+			break;
+
+		entry->rx_hdr->flags = 0;
+		iowrite32(entry->index, &qp->rx_info->entry);
+
+		cb_data = entry->cb_data;
+		len = entry->len;
+
+		list_move_tail(&entry->entry, &qp->rx_free_q);
 
-	hdr->flags = 0;
+		spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
 
-	iowrite32(entry->index, &qp->rx_info->entry);
+		if (qp->rx_handler && qp->client_ready)
+			qp->rx_handler(qp, qp->cb_data, cb_data, len);
 
-	ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
+		spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
+	}
 
-	if (qp->rx_handler && qp->client_ready)
-		qp->rx_handler(qp, qp->cb_data, cb_data, len);
+	spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
+}
+
+static void ntb_rx_copy_callback(void *data)
+{
+	struct ntb_queue_entry *entry = data;
+
+	entry->flags |= DESC_DONE_FLAG;
+
+	ntb_complete_rxc(entry->qp);
 }
 
 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
@@ -1138,19 +1185,18 @@ static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
 	ntb_rx_copy_callback(entry);
 }
 
-static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset,
-			 size_t len)
+static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
 {
 	struct dma_async_tx_descriptor *txd;
 	struct ntb_transport_qp *qp = entry->qp;
 	struct dma_chan *chan = qp->dma_chan;
 	struct dma_device *device;
-	size_t pay_off, buff_off;
+	size_t pay_off, buff_off, len;
 	struct dmaengine_unmap_data *unmap;
 	dma_cookie_t cookie;
 	void *buf = entry->buf;
 
-	entry->len = len;
+	len = entry->len;
 
 	if (!chan)
 		goto err;
@@ -1226,7 +1272,6 @@ static int ntb_process_rxc(struct ntb_transport_qp *qp)
 	struct ntb_payload_header *hdr;
 	struct ntb_queue_entry *entry;
 	void *offset;
-	int rc;
 
 	offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
 	hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
@@ -1255,65 +1300,43 @@ static int ntb_process_rxc(struct ntb_transport_qp *qp)
 		return -EIO;
 	}
 
-	entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
+	entry = ntb_list_mv(&qp->ntb_rx_q_lock, &qp->rx_pend_q, &qp->rx_post_q);
 	if (!entry) {
 		dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
 		qp->rx_err_no_buf++;
-
-		rc = -ENOMEM;
-		goto err;
+		return -EAGAIN;
 	}
 
+	entry->rx_hdr = hdr;
+	entry->index = qp->rx_index;
+
 	if (hdr->len > entry->len) {
 		dev_dbg(&qp->ndev->pdev->dev,
 			"receive buffer overflow! Wanted %d got %d\n",
 			hdr->len, entry->len);
 		qp->rx_err_oflow++;
 
-		rc = -EIO;
-		goto err;
-	}
+		entry->len = -EIO;
+		entry->flags |= DESC_DONE_FLAG;
 
-	dev_dbg(&qp->ndev->pdev->dev,
-		"RX OK index %u ver %u size %d into buf size %d\n",
-		qp->rx_index, hdr->ver, hdr->len, entry->len);
+		ntb_complete_rxc(qp);
+	} else {
+		dev_dbg(&qp->ndev->pdev->dev,
+			"RX OK index %u ver %u size %d into buf size %d\n",
+			qp->rx_index, hdr->ver, hdr->len, entry->len);
 
-	qp->rx_bytes += hdr->len;
-	qp->rx_pkts++;
+		qp->rx_bytes += hdr->len;
+		qp->rx_pkts++;
 
-	entry->index = qp->rx_index;
-	entry->rx_hdr = hdr;
+		entry->len = hdr->len;
 
-	ntb_async_rx(entry, offset, hdr->len);
+		ntb_async_rx(entry, offset);
+	}
 
 	qp->rx_index++;
 	qp->rx_index %= qp->rx_max_entry;
 
 	return 0;
-
-err:
-	/* FIXME: if this syncrhonous update of the rx_index gets ahead of
-	 * asyncrhonous ntb_rx_copy_callback of previous entry, there are three
-	 * scenarios:
-	 *
-	 * 1) The peer might miss this update, but observe the update
-	 * from the memcpy completion callback.  In this case, the buffer will
-	 * not be freed on the peer to be reused for a different packet.  The
-	 * successful rx of a later packet would clear the condition, but the
-	 * condition could persist if several rx fail in a row.
-	 *
-	 * 2) The peer may observe this update before the asyncrhonous copy of
-	 * prior packets is completed.  The peer may overwrite the buffers of
-	 * the prior packets before they are copied.
-	 *
-	 * 3) Both: the peer may observe the update, and then observe the index
-	 * decrement by the asynchronous completion callback.  Who knows what
-	 * badness that will cause.
-	 */
-	hdr->flags = 0;
-	iowrite32(qp->rx_index, &qp->rx_info->entry);
-
-	return rc;
 }
 
 static void ntb_transport_rxc_db(unsigned long data)
@@ -1333,7 +1356,7 @@ static void ntb_transport_rxc_db(unsigned long data)
 			break;
 	}
 
-	if (qp->dma_chan)
+	if (i && qp->dma_chan)
 		dma_async_issue_pending(qp->dma_chan);
 
 	if (i == qp->rx_max_entry) {
@@ -1609,7 +1632,7 @@ ntb_transport_create_queue(void *data, struct device *client_dev,
 			goto err1;
 
 		entry->qp = qp;
-		ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
+		ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
 			     &qp->rx_free_q);
 	}
 
@@ -1634,7 +1657,7 @@ err2:
 	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
 		kfree(entry);
 err1:
-	while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
+	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
 		kfree(entry);
 	if (qp->dma_chan)
 		dma_release_channel(qp->dma_chan);
@@ -1689,11 +1712,16 @@ void ntb_transport_free_queue(struct ntb_transport_qp *qp)
 	qp->tx_handler = NULL;
 	qp->event_handler = NULL;
 
-	while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
+	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
 		kfree(entry);
 
-	while ((entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q))) {
-		dev_warn(&pdev->dev, "Freeing item from a non-empty queue\n");
+	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q))) {
+		dev_warn(&pdev->dev, "Freeing item from non-empty rx_pend_q\n");
+		kfree(entry);
+	}
+
+	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_post_q))) {
+		dev_warn(&pdev->dev, "Freeing item from non-empty rx_post_q\n");
 		kfree(entry);
 	}
 
@@ -1724,14 +1752,14 @@ void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
 	if (!qp || qp->client_ready)
 		return NULL;
 
-	entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
+	entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q);
 	if (!entry)
 		return NULL;
 
 	buf = entry->cb_data;
 	*len = entry->len;
 
-	ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
+	ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_free_q);
 
 	return buf;
 }
@@ -1757,15 +1785,18 @@ int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
 	if (!qp)
 		return -EINVAL;
 
-	entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q);
+	entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q);
 	if (!entry)
 		return -ENOMEM;
 
 	entry->cb_data = cb;
 	entry->buf = data;
 	entry->len = len;
+	entry->flags = 0;
+
+	ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_pend_q);
 
-	ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry, &qp->rx_pend_q);
+	tasklet_schedule(&qp->rxc_db_work);
 
 	return 0;
 }