[PATCH v2 0/7] NTB: Bug Fixes

[PATCH v2 0/7] NTB: Bug Fixes

[Allen Hubbe]

I split the v1 series into two series.  These patches are bug fixes.

These are in github.com/allenbh/linux.git branch ntb/master.

Allen Hubbe (4):
  NTB: Fix ntb_transport out-of-order RX update
  NTB: Schedule to receive on QP link up
  NTB: Fix zero size or integer overflow in ntb_set_mw
  NTB: Fix dereference before check

Dave Jiang (3):
  NTB: Fix transport stats for multiple devices
  NTB: ntb_netdev not covering all receive errors
  NTB: Fix oops in debugfs when transport is half-up

 drivers/net/ntb_netdev.c    |   9 +-
 drivers/ntb/ntb_transport.c | 201 +++++++++++++++++++++++++++-----------------
 2 files changed, 132 insertions(+), 78 deletions(-)

-- 
2.5.0.rc1

[PATCH v2 1/7] NTB: Fix ntb_transport out-of-order RX update

[Allen Hubbe]

It was possible for a synchronous update of the RX index in the error
case to get ahead of the asynchronous RX index update in the normal
case.  Change the RX processing to preserve an RX completion order.

There were two error cases.  First, if a buffer is not present to
receive data, there would be no queue entry to preserve the RX
completion order.  Instead of dropping the RX frame, leave the RX frame
in the ring.  Schedule RX processing when RX entries are enqueued, in
case there are RX frames waiting in the ring to be received.

Second, if a buffer is too small to receive data, drop the frame in the
ring, mark the RX entry as done, and indicate the error in the RX entry
length.  Check for a negative length in the receive callback in
ntb_netdev, and count occurrences as rx_length_errors.

Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
---
 drivers/net/ntb_netdev.c    |   7 ++
 drivers/ntb/ntb_transport.c | 169 ++++++++++++++++++++++++++------------------
 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;
 }
-- 
2.5.0.rc1

[PATCH v2 2/7] NTB: Fix transport stats for multiple devices

[Allen Hubbe]

From: Dave Jiang <dave.jiang@intel.com>

Currently the debugfs does not have files for all NTB transport queue
pairs.  When there are multiple NTBs present in a system, the QP names
of the last transport clobber the names of previously added transport
QPs.  Only the last added QPs can be observed via debugfs.

Create a directory per NTB transport to associate the QPs with that
transport.  Name the directory the same as the PCI device.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/ntb/ntb_transport.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 98e58c765f2e..25e973ff64cf 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -212,6 +212,8 @@ struct ntb_transport_ctx {
 	bool link_is_up;
 	struct delayed_work link_work;
 	struct work_struct link_cleanup;
+
+	struct dentry *debugfs_node_dir;
 };
 
 enum {
@@ -945,12 +947,12 @@ static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
 	qp->tx_max_frame = min(transport_mtu, tx_size / 2);
 	qp->tx_max_entry = tx_size / qp->tx_max_frame;
 
-	if (nt_debugfs_dir) {
+	if (nt->debugfs_node_dir) {
 		char debugfs_name[4];
 
 		snprintf(debugfs_name, 4, "qp%d", qp_num);
 		qp->debugfs_dir = debugfs_create_dir(debugfs_name,
-						     nt_debugfs_dir);
+						     nt->debugfs_node_dir);
 
 		qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
 							qp->debugfs_dir, qp,
@@ -1053,6 +1055,12 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
 		goto err2;
 	}
 
+	if (nt_debugfs_dir) {
+		nt->debugfs_node_dir =
+			debugfs_create_dir(pci_name(ndev->pdev),
+					   nt_debugfs_dir);
+	}
+
 	for (i = 0; i < qp_count; i++) {
 		rc = ntb_transport_init_queue(nt, i);
 		if (rc)
-- 
2.5.0.rc1

[PATCH v2 3/7] NTB: ntb_netdev not covering all receive errors

[Allen Hubbe]

From: Dave Jiang <dave.jiang@intel.com>

ntb_netdev is allowing the link to come up even when -ENOMEM is returned
from ntb_transport_rx_enqueue.  Fix to cover all possible errors.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/net/ntb_netdev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ntb_netdev.c b/drivers/net/ntb_netdev.c
index 5f1ee7c05f68..d8757bf9ad75 100644
--- a/drivers/net/ntb_netdev.c
+++ b/drivers/net/ntb_netdev.c
@@ -191,7 +191,7 @@ static int ntb_netdev_open(struct net_device *ndev)
 
 		rc = ntb_transport_rx_enqueue(dev->qp, skb, skb->data,
 					      ndev->mtu + ETH_HLEN);
-		if (rc == -EINVAL) {
+		if (rc) {
 			dev_kfree_skb(skb);
 			goto err;
 		}
-- 
2.5.0.rc1

[PATCH v2 4/7] NTB: Fix oops in debugfs when transport is half-up

[Allen Hubbe]

From: Dave Jiang <dave.jiang@intel.com>

When the remote side is not up, we do not have all the context for the
transport, and that causes NULL ptr access. Have the debugfs reads check
to see if transport is up before we make access.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/ntb/ntb_transport.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 25e973ff64cf..a049f96fab8d 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -439,13 +439,17 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 	char *buf;
 	ssize_t ret, out_offset, out_count;
 
+	qp = filp->private_data;
+
+	if (!qp || !qp->link_is_up)
+		return 0;
+
 	out_count = 1000;
 
 	buf = kmalloc(out_count, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
-	qp = filp->private_data;
 	out_offset = 0;
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "NTB QP stats\n");
-- 
2.5.0.rc1

[PATCH v2 5/7] NTB: Schedule to receive on QP link up

[Allen Hubbe]

Schedule to receive on QP link up, to make sure that the doorbell is
properly cleared for interrupts.

Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
---
 drivers/ntb/ntb_transport.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index a049f96fab8d..b82171e3e07d 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -895,6 +895,8 @@ static void ntb_qp_link_work(struct work_struct *work)
 
 		if (qp->event_handler)
 			qp->event_handler(qp->cb_data, qp->link_is_up);
+
+		tasklet_schedule(&qp->rxc_db_work);
 	} else if (nt->link_is_up)
 		schedule_delayed_work(&qp->link_work,
 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
-- 
2.5.0.rc1

[PATCH v2 6/7] NTB: Fix zero size or integer overflow in ntb_set_mw

[Allen Hubbe]

A plain 32 bit integer will overflow for values over 4GiB.

Change the plain integer size to the appropriate size type in
ntb_set_mw.  Change the type of the size parameter and two local
variables used for size.

Even if there is no overflow, a size of zero is invalid here.

Reported-by: Juyoung Jung <jjung@micron.com>
Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
---
 drivers/ntb/ntb_transport.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index b82171e3e07d..04e6c345419c 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -629,13 +629,16 @@ static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
 }
 
 static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
-		      unsigned int size)
+		      resource_size_t size)
 {
 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
 	struct pci_dev *pdev = nt->ndev->pdev;
-	unsigned int xlat_size, buff_size;
+	size_t xlat_size, buff_size;
 	int rc;
 
+	if (!size)
+		return -EINVAL;
+
 	xlat_size = round_up(size, mw->xlat_align_size);
 	buff_size = round_up(size, mw->xlat_align);
 
@@ -655,7 +658,7 @@ static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
 	if (!mw->virt_addr) {
 		mw->xlat_size = 0;
 		mw->buff_size = 0;
-		dev_err(&pdev->dev, "Unable to alloc MW buff of size %d\n",
+		dev_err(&pdev->dev, "Unable to alloc MW buff of size %lu\n",
 			buff_size);
 		return -ENOMEM;
 	}
-- 
2.5.0.rc1

[PATCH v2 7/7] NTB: Fix dereference before check

[Allen Hubbe]

Remove early dereference of a pointer that is checked later in the code.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
---
 drivers/ntb/ntb_transport.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 04e6c345419c..3363a8968f9d 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -1692,7 +1692,6 @@ EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
  */
 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
 {
-	struct ntb_transport_ctx *nt = qp->transport;
 	struct pci_dev *pdev;
 	struct ntb_queue_entry *entry;
 	u64 qp_bit;
@@ -1745,7 +1744,7 @@ void ntb_transport_free_queue(struct ntb_transport_qp *qp)
 	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
 		kfree(entry);
 
-	nt->qp_bitmap_free |= qp_bit;
+	qp->transport->qp_bitmap_free |= qp_bit;
 
 	dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
 }
-- 
2.5.0.rc1

[PATCH v2 00/14] NTB: Performance and Usability Features

[Allen Hubbe]

I split the v1 series into two series.  These patches are _not_ bug fixes.

Numbering in this v2 starts at 8.  This is the second half of the patches.

Module parameters are removed from "Add flow control".

These are in github.com/allenbh/linux.git branch ntb/next.

Allen Hubbe (1):
  NTB: Remove dma_sync_wait from ntb_async_rx

Dave Jiang (5):
  NTB: Add flow control to the ntb_netdev
  NTB: Add PCI Device IDs for Broadwell Xeon
  NTB: Make the transport list in order of discovery
  NTB: Clean up QP stats info
  NTB: Use unique DMA channels for TX and RX

Jon Mason (1):
  NTB: Add list to MAINTAINERS

 MAINTAINERS                         |   2 +
 drivers/net/ntb_netdev.c            |  77 ++++++++++++++++++++++
 drivers/ntb/hw/intel/ntb_hw_intel.c |  15 +++++
 drivers/ntb/hw/intel/ntb_hw_intel.h |   3 +
 drivers/ntb/ntb_transport.c         | 126 ++++++++++++++++++++++++++----------
 include/linux/ntb_transport.h       |   1 +
 6 files changed, 189 insertions(+), 35 deletions(-)

-- 
2.5.0.rc1

[PATCH v2 08/14] NTB: Add list to MAINTAINERS

[Allen Hubbe]

From: Jon Mason <jdmason@kudzu.us>

Add the new NTB mailing list to MAINTAINERS

Signed-off-by: Jon Mason <jdmason@kudzu.us>
---
 MAINTAINERS | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 8133cefb6b6e..6a634882b420 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7223,6 +7223,7 @@ NTB DRIVER CORE
 M:	Jon Mason <jdmason@kudzu.us>
 M:	Dave Jiang <dave.jiang@intel.com>
 M:	Allen Hubbe <Allen.Hubbe@emc.com>
+L:	linux-ntb@googlegroups.com
 S:	Supported
 W:	https://github.com/jonmason/ntb/wiki
 T:	git git://github.com/jonmason/ntb.git
@@ -7234,6 +7235,7 @@ F:	include/linux/ntb_transport.h
 NTB INTEL DRIVER
 M:	Jon Mason <jdmason@kudzu.us>
 M:	Dave Jiang <dave.jiang@intel.com>
+L:	linux-ntb@googlegroups.com
 S:	Supported
 W:	https://github.com/jonmason/ntb/wiki
 T:	git git://github.com/jonmason/ntb.git
-- 
2.5.0.rc1

[PATCH v2 09/14] NTB: Add flow control to the ntb_netdev

[Allen Hubbe]

From: Dave Jiang <dave.jiang@intel.com>

Right now if we push the NTB really hard, we start dropping packets due
to not able to process the packets fast enough. We need to st:qop the
upper layer from flooding us when that happens.

A timer is necessary in order to restart the queue once the resource has
been processed on the receive side. Due to the way NTB is setup, the
resources on the tx side are tied to the processing of the rx side and
there's no async way to know when the rx side has released those
resources.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/net/ntb_netdev.c      | 77 +++++++++++++++++++++++++++++++++++++++++++
 drivers/ntb/ntb_transport.c   | 18 +++++++++-
 include/linux/ntb_transport.h |  1 +
 3 files changed, 95 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ntb_netdev.c b/drivers/net/ntb_netdev.c
index d8757bf9ad75..a9acf7156855 100644
--- a/drivers/net/ntb_netdev.c
+++ b/drivers/net/ntb_netdev.c
@@ -61,11 +61,21 @@ MODULE_VERSION(NTB_NETDEV_VER);
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Intel Corporation");
 
+/* Time in usecs for tx resource reaper */
+static unsigned int tx_time = 1;
+
+/* Number of descriptors to free before resuming tx */
+static unsigned int tx_start = 10;
+
+/* Number of descriptors still available before stop upper layer tx */
+static unsigned int tx_stop = 5;
+
 struct ntb_netdev {
 	struct list_head list;
 	struct pci_dev *pdev;
 	struct net_device *ndev;
 	struct ntb_transport_qp *qp;
+	struct timer_list tx_timer;
 };
 
 #define	NTB_TX_TIMEOUT_MS	1000
@@ -136,11 +146,42 @@ enqueue_again:
 	}
 }
 
+static int __ntb_netdev_maybe_stop_tx(struct net_device *netdev,
+				      struct ntb_transport_qp *qp, int size)
+{
+	struct ntb_netdev *dev = netdev_priv(netdev);
+
+	netif_stop_queue(netdev);
+	/* Make sure to see the latest value of ntb_transport_tx_free_entry()
+	 * since the queue was last started.
+	 */
+	smp_mb();
+
+	if (likely(ntb_transport_tx_free_entry(qp) < size)) {
+		mod_timer(&dev->tx_timer, jiffies + usecs_to_jiffies(tx_time));
+		return -EBUSY;
+	}
+
+	netif_start_queue(netdev);
+	return 0;
+}
+
+static int ntb_netdev_maybe_stop_tx(struct net_device *ndev,
+				    struct ntb_transport_qp *qp, int size)
+{
+	if (netif_queue_stopped(ndev) ||
+	    (ntb_transport_tx_free_entry(qp) >= size))
+		return 0;
+
+	return __ntb_netdev_maybe_stop_tx(ndev, qp, size);
+}
+
 static void ntb_netdev_tx_handler(struct ntb_transport_qp *qp, void *qp_data,
 				  void *data, int len)
 {
 	struct net_device *ndev = qp_data;
 	struct sk_buff *skb;
+	struct ntb_netdev *dev = netdev_priv(ndev);
 
 	skb = data;
 	if (!skb || !ndev)
@@ -155,6 +196,15 @@ static void ntb_netdev_tx_handler(struct ntb_transport_qp *qp, void *qp_data,
 	}
 
 	dev_kfree_skb(skb);
+
+	if (ntb_transport_tx_free_entry(dev->qp) >= tx_start) {
+		/* Make sure anybody stopping the queue after this sees the new
+		 * value of ntb_transport_tx_free_entry()
+		 */
+		smp_mb();
+		if (netif_queue_stopped(ndev))
+			netif_wake_queue(ndev);
+	}
 }
 
 static netdev_tx_t ntb_netdev_start_xmit(struct sk_buff *skb,
@@ -163,10 +213,15 @@ static netdev_tx_t ntb_netdev_start_xmit(struct sk_buff *skb,
 	struct ntb_netdev *dev = netdev_priv(ndev);
 	int rc;
 
+	ntb_netdev_maybe_stop_tx(ndev, dev->qp, tx_stop);
+
 	rc = ntb_transport_tx_enqueue(dev->qp, skb, skb->data, skb->len);
 	if (rc)
 		goto err;
 
+	/* check for next submit */
+	ntb_netdev_maybe_stop_tx(ndev, dev->qp, tx_stop);
+
 	return NETDEV_TX_OK;
 
 err:
@@ -175,6 +230,23 @@ err:
 	return NETDEV_TX_BUSY;
 }
 
+static void ntb_netdev_tx_timer(unsigned long data)
+{
+	struct net_device *ndev = (struct net_device *)data;
+	struct ntb_netdev *dev = netdev_priv(ndev);
+
+	if (ntb_transport_tx_free_entry(dev->qp) < tx_stop) {
+		mod_timer(&dev->tx_timer, jiffies + msecs_to_jiffies(tx_time));
+	} else {
+		/* Make sure anybody stopping the queue after this sees the new
+		 * value of ntb_transport_tx_free_entry()
+		 */
+		smp_mb();
+		if (netif_queue_stopped(ndev))
+			netif_wake_queue(ndev);
+	}
+}
+
 static int ntb_netdev_open(struct net_device *ndev)
 {
 	struct ntb_netdev *dev = netdev_priv(ndev);
@@ -197,8 +269,11 @@ static int ntb_netdev_open(struct net_device *ndev)
 		}
 	}
 
+	setup_timer(&dev->tx_timer, ntb_netdev_tx_timer, (unsigned long)ndev);
+
 	netif_carrier_off(ndev);
 	ntb_transport_link_up(dev->qp);
+	netif_start_queue(ndev);
 
 	return 0;
 
@@ -219,6 +294,8 @@ static int ntb_netdev_close(struct net_device *ndev)
 	while ((skb = ntb_transport_rx_remove(dev->qp, &len)))
 		dev_kfree_skb(skb);
 
+	del_timer_sync(&dev->tx_timer);
+
 	return 0;
 }
 
diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 3363a8968f9d..8c9d50d50e92 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -494,6 +494,12 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 			       "tx_index - \t%u\n", qp->tx_index);
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "tx_max_entry - \t%u\n", qp->tx_max_entry);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "qp->remote_rx_info->entry - \t%u\n",
+			       qp->remote_rx_info->entry);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "free tx - \t%u\n",
+			       ntb_transport_tx_free_entry(qp));
 
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "\nQP Link %s\n",
@@ -535,6 +541,7 @@ static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
 	}
 	entry = list_first_entry(list, struct ntb_queue_entry, entry);
 	list_del(&entry->entry);
+
 out:
 	spin_unlock_irqrestore(lock, flags);
 
@@ -1843,7 +1850,7 @@ int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
 	entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
 	if (!entry) {
 		qp->tx_err_no_buf++;
-		return -ENOMEM;
+		return -EBUSY;
 	}
 
 	entry->cb_data = cb;
@@ -1969,6 +1976,15 @@ unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
 }
 EXPORT_SYMBOL_GPL(ntb_transport_max_size);
 
+unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
+{
+	unsigned int head = qp->tx_index;
+	unsigned int tail = qp->remote_rx_info->entry;
+
+	return tail > head ? tail - head : qp->tx_max_entry + tail - head;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);
+
 static void ntb_transport_doorbell_callback(void *data, int vector)
 {
 	struct ntb_transport_ctx *nt = data;
diff --git a/include/linux/ntb_transport.h b/include/linux/ntb_transport.h
index 2862861366a5..7243eb98a722 100644
--- a/include/linux/ntb_transport.h
+++ b/include/linux/ntb_transport.h
@@ -83,3 +83,4 @@ void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len);
 void ntb_transport_link_up(struct ntb_transport_qp *qp);
 void ntb_transport_link_down(struct ntb_transport_qp *qp);
 bool ntb_transport_link_query(struct ntb_transport_qp *qp);
+unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp);
-- 
2.5.0.rc1

[PATCH v2 10/14] NTB: Add PCI Device IDs for Broadwell Xeon

[Allen Hubbe]

From: Dave Jiang <dave.jiang@intel.com>

Adding PCI Device IDs for B2B (back to back), RP (root port, primary),
and TB (transparent bridge, secondary) devices.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/ntb/hw/intel/ntb_hw_intel.c | 15 +++++++++++++++
 drivers/ntb/hw/intel/ntb_hw_intel.h |  3 +++
 2 files changed, 18 insertions(+)

diff --git a/drivers/ntb/hw/intel/ntb_hw_intel.c b/drivers/ntb/hw/intel/ntb_hw_intel.c
index 87751cfd6f4f..c2bc56b67e63 100644
--- a/drivers/ntb/hw/intel/ntb_hw_intel.c
+++ b/drivers/ntb/hw/intel/ntb_hw_intel.c
@@ -190,14 +190,17 @@ static inline int pdev_is_xeon(struct pci_dev *pdev)
 	case PCI_DEVICE_ID_INTEL_NTB_SS_SNB:
 	case PCI_DEVICE_ID_INTEL_NTB_SS_IVT:
 	case PCI_DEVICE_ID_INTEL_NTB_SS_HSX:
+	case PCI_DEVICE_ID_INTEL_NTB_SS_BDX:
 	case PCI_DEVICE_ID_INTEL_NTB_PS_JSF:
 	case PCI_DEVICE_ID_INTEL_NTB_PS_SNB:
 	case PCI_DEVICE_ID_INTEL_NTB_PS_IVT:
 	case PCI_DEVICE_ID_INTEL_NTB_PS_HSX:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_BDX:
 	case PCI_DEVICE_ID_INTEL_NTB_B2B_JSF:
 	case PCI_DEVICE_ID_INTEL_NTB_B2B_SNB:
 	case PCI_DEVICE_ID_INTEL_NTB_B2B_IVT:
 	case PCI_DEVICE_ID_INTEL_NTB_B2B_HSX:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_BDX:
 		return 1;
 	}
 	return 0;
@@ -1843,6 +1846,9 @@ static int xeon_init_dev(struct intel_ntb_dev *ndev)
 	case PCI_DEVICE_ID_INTEL_NTB_SS_HSX:
 	case PCI_DEVICE_ID_INTEL_NTB_PS_HSX:
 	case PCI_DEVICE_ID_INTEL_NTB_B2B_HSX:
+	case PCI_DEVICE_ID_INTEL_NTB_SS_BDX:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_BDX:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_BDX:
 		ndev->hwerr_flags |= NTB_HWERR_SDOORBELL_LOCKUP;
 		break;
 	}
@@ -1857,6 +1863,9 @@ static int xeon_init_dev(struct intel_ntb_dev *ndev)
 	case PCI_DEVICE_ID_INTEL_NTB_SS_HSX:
 	case PCI_DEVICE_ID_INTEL_NTB_PS_HSX:
 	case PCI_DEVICE_ID_INTEL_NTB_B2B_HSX:
+	case PCI_DEVICE_ID_INTEL_NTB_SS_BDX:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_BDX:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_BDX:
 		ndev->hwerr_flags |= NTB_HWERR_SB01BASE_LOCKUP;
 		break;
 	}
@@ -1878,6 +1887,9 @@ static int xeon_init_dev(struct intel_ntb_dev *ndev)
 	case PCI_DEVICE_ID_INTEL_NTB_SS_HSX:
 	case PCI_DEVICE_ID_INTEL_NTB_PS_HSX:
 	case PCI_DEVICE_ID_INTEL_NTB_B2B_HSX:
+	case PCI_DEVICE_ID_INTEL_NTB_SS_BDX:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_BDX:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_BDX:
 		ndev->hwerr_flags |= NTB_HWERR_B2BDOORBELL_BIT14;
 		break;
 	}
@@ -2234,14 +2246,17 @@ static const struct pci_device_id intel_ntb_pci_tbl[] = {
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_SNB)},
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_IVT)},
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_HSX)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_BDX)},
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_PS_JSF)},
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_PS_SNB)},
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_PS_IVT)},
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_PS_HSX)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_PS_BDX)},
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_SS_JSF)},
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_SS_SNB)},
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_SS_IVT)},
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_SS_HSX)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_SS_BDX)},
 	{0}
 };
 MODULE_DEVICE_TABLE(pci, intel_ntb_pci_tbl);
diff --git a/drivers/ntb/hw/intel/ntb_hw_intel.h b/drivers/ntb/hw/intel/ntb_hw_intel.h
index 7ddaf387b679..ea0612f797df 100644
--- a/drivers/ntb/hw/intel/ntb_hw_intel.h
+++ b/drivers/ntb/hw/intel/ntb_hw_intel.h
@@ -67,6 +67,9 @@
 #define PCI_DEVICE_ID_INTEL_NTB_PS_HSX	0x2F0E
 #define PCI_DEVICE_ID_INTEL_NTB_SS_HSX	0x2F0F
 #define PCI_DEVICE_ID_INTEL_NTB_B2B_BWD	0x0C4E
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_BDX	0x6F0D
+#define PCI_DEVICE_ID_INTEL_NTB_PS_BDX	0x6F0E
+#define PCI_DEVICE_ID_INTEL_NTB_SS_BDX	0x6F0F
 
 /* Intel Xeon hardware */
 
-- 
2.5.0.rc1

[PATCH v2 11/14] NTB: Make the transport list in order of discovery

[Allen Hubbe]

From: Dave Jiang <dave.jiang@intel.com>

The list should be added from the bottom and not the top in order to
ensure the transport is provided in the same order to clients as ntb
devices are discovered.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/ntb/ntb_transport.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 8c9d50d50e92..55c26c59f4fe 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -297,7 +297,7 @@ static LIST_HEAD(ntb_transport_list);
 
 static int ntb_bus_init(struct ntb_transport_ctx *nt)
 {
-	list_add(&nt->entry, &ntb_transport_list);
+	list_add_tail(&nt->entry, &ntb_transport_list);
 	return 0;
 }
 
-- 
2.5.0.rc1

[PATCH v2 12/14] NTB: Clean up QP stats info

[Allen Hubbe]

From: Dave Jiang <dave.jiang@intel.com>

Make QP stats info more readable for debugging purposes.  Also add an
entry to indicate whether DMA is being used.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/ntb/ntb_transport.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 55c26c59f4fe..c283d1c2cb72 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -452,7 +452,7 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 
 	out_offset = 0;
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
-			       "NTB QP stats\n");
+			       "\nNTB QP stats:\n\n");
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "rx_bytes - \t%llu\n", qp->rx_bytes);
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
@@ -470,11 +470,11 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "rx_err_ver - \t%llu\n", qp->rx_err_ver);
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
-			       "rx_buff - \t%p\n", qp->rx_buff);
+			       "rx_buff - \t0x%p\n", qp->rx_buff);
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "rx_index - \t%u\n", qp->rx_index);
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
-			       "rx_max_entry - \t%u\n", qp->rx_max_entry);
+			       "rx_max_entry - \t%u\n\n", qp->rx_max_entry);
 
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "tx_bytes - \t%llu\n", qp->tx_bytes);
@@ -489,21 +489,28 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
-			       "tx_mw - \t%p\n", qp->tx_mw);
+			       "tx_mw - \t0x%p\n", qp->tx_mw);
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
-			       "tx_index - \t%u\n", qp->tx_index);
+			       "tx_index (H) - \t%u\n", qp->tx_index);
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
-			       "tx_max_entry - \t%u\n", qp->tx_max_entry);
-	out_offset += snprintf(buf + out_offset, out_count - out_offset,
-			       "qp->remote_rx_info->entry - \t%u\n",
+			       "RRI (T) - \t%u\n",
 			       qp->remote_rx_info->entry);
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "tx_max_entry - \t%u\n", qp->tx_max_entry);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "free tx - \t%u\n",
 			       ntb_transport_tx_free_entry(qp));
 
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
-			       "\nQP Link %s\n",
+			       "\n");
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "Using DMA - \t%s\n", use_dma ? "Yes" : "No");
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "QP Link - \t%s\n",
 			       qp->link_is_up ? "Up" : "Down");
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "\n");
+
 	if (out_offset > out_count)
 		out_offset = out_count;
 
-- 
2.5.0.rc1

[PATCH v2 13/14] NTB: Remove dma_sync_wait from ntb_async_rx

[Allen Hubbe]

The dma_sync_wait can hurt the performance of workloads mixed with both
large and small frames.  Large frames will be copied using the dma
engine.  Small frames will be copied by the cpu.  The dma_sync_wait
prevents the cpu and dma engine copying in parallel.

In the period where the cpu is copying, the dma engine is stopped.  The
dma engine is not doing any useful work to copy large frames during that
time, and the additional time to restart the dma engine for the next
large frame.  This will decrease the throughput for the portion of a
workload with large frames.

In the period where the dma engine is copying, the cpu is held up
waiting for dma to complete.  The small frames processing will be
delayed until the dma is complete.  The RX frames are completed
in-order, and the processing of small frames takes very little time, so
dma_sync_wait may have an insignificant impact on the respose time of
frames.  The more significant impact is to the system, because the delay
in dma_sync_wait is implemented as busy non-blocking wait.  This can
prevent the delayed core from doing any useful work, even if it could be
processing work for other drivers, unrelated to transport RX processing.

After applying the earlier patch to fix out-of-order RX acknoledgement,
the dma_sync_wait is no longer necessary.  Remove it, so that cpu memcpy
will proceed immediately for small frames, in parallel with ongoing dma
for large frames.  Do not hold up the cpu from doing work while dma is
in progress.  The prior fix will continue to ensure in-order completion
of the RX frames to the upper layer, and in-order delivery of the RX
acknoledgement.

Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
---
 drivers/ntb/ntb_transport.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index c283d1c2cb72..1ddf84ca721a 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -1233,18 +1233,18 @@ static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
 		goto err;
 
 	if (len < copy_bytes)
-		goto err_wait;
+		goto err;
 
 	device = chan->device;
 	pay_off = (size_t)offset & ~PAGE_MASK;
 	buff_off = (size_t)buf & ~PAGE_MASK;
 
 	if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
-		goto err_wait;
+		goto err;
 
 	unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
 	if (!unmap)
-		goto err_wait;
+		goto err;
 
 	unmap->len = len;
 	unmap->addr[0] = dma_map_page(device->dev, virt_to_page(offset),
@@ -1287,12 +1287,6 @@ err_set_unmap:
 	dmaengine_unmap_put(unmap);
 err_get_unmap:
 	dmaengine_unmap_put(unmap);
-err_wait:
-	/* If the callbacks come out of order, the writing of the index to the
-	 * last completed will be out of order.  This may result in the
-	 * receive stalling forever.
-	 */
-	dma_sync_wait(chan, qp->last_cookie);
 err:
 	ntb_memcpy_rx(entry, offset);
 	qp->rx_memcpy++;
-- 
2.5.0.rc1

[PATCH v2 14/14] NTB: Use unique DMA channels for TX and RX

[Allen Hubbe]

From: Dave Jiang <dave.jiang@intel.com>

Allocate two DMA channels, one for TX operation and one for RX
operation, instead of having one DMA channel for everything. This
provides slightly better performance, and also will make error handling
cleaner later on.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/ntb/ntb_transport.c | 77 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 58 insertions(+), 19 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 1ddf84ca721a..c64de9b99742 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -119,7 +119,8 @@ struct ntb_transport_qp {
 	struct ntb_transport_ctx *transport;
 	struct ntb_dev *ndev;
 	void *cb_data;
-	struct dma_chan *dma_chan;
+	struct dma_chan *tx_dma_chan;
+	struct dma_chan *rx_dma_chan;
 
 	bool client_ready;
 	bool link_is_up;
@@ -504,7 +505,11 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "\n");
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
-			       "Using DMA - \t%s\n", use_dma ? "Yes" : "No");
+			       "Using TX DMA - \t%s\n",
+			       qp->tx_dma_chan ? "Yes" : "No");
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "Using RX DMA - \t%s\n",
+			       qp->rx_dma_chan ? "Yes" : "No");
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "QP Link - \t%s\n",
 			       qp->link_is_up ? "Up" : "Down");
@@ -1220,7 +1225,7 @@ 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_chan *chan = qp->rx_dma_chan;
 	struct dma_device *device;
 	size_t pay_off, buff_off, len;
 	struct dmaengine_unmap_data *unmap;
@@ -1381,8 +1386,8 @@ static void ntb_transport_rxc_db(unsigned long data)
 			break;
 	}
 
-	if (i && qp->dma_chan)
-		dma_async_issue_pending(qp->dma_chan);
+	if (i && qp->rx_dma_chan)
+		dma_async_issue_pending(qp->rx_dma_chan);
 
 	if (i == qp->rx_max_entry) {
 		/* there is more work to do */
@@ -1449,7 +1454,7 @@ static void ntb_async_tx(struct ntb_transport_qp *qp,
 {
 	struct ntb_payload_header __iomem *hdr;
 	struct dma_async_tx_descriptor *txd;
-	struct dma_chan *chan = qp->dma_chan;
+	struct dma_chan *chan = qp->tx_dma_chan;
 	struct dma_device *device;
 	size_t dest_off, buff_off;
 	struct dmaengine_unmap_data *unmap;
@@ -1642,14 +1647,27 @@ ntb_transport_create_queue(void *data, struct device *client_dev,
 	dma_cap_set(DMA_MEMCPY, dma_mask);
 
 	if (use_dma) {
-		qp->dma_chan = dma_request_channel(dma_mask, ntb_dma_filter_fn,
-						   (void *)(unsigned long)node);
-		if (!qp->dma_chan)
-			dev_info(&pdev->dev, "Unable to allocate DMA channel\n");
+		qp->tx_dma_chan =
+			dma_request_channel(dma_mask, ntb_dma_filter_fn,
+					    (void *)(unsigned long)node);
+		if (!qp->tx_dma_chan)
+			dev_info(&pdev->dev, "Unable to allocate TX DMA channel\n");
+
+		qp->rx_dma_chan =
+			dma_request_channel(dma_mask, ntb_dma_filter_fn,
+					    (void *)(unsigned long)node);
+		if (!qp->rx_dma_chan)
+			dev_info(&pdev->dev, "Unable to allocate RX DMA channel\n");
 	} else {
-		qp->dma_chan = NULL;
+		qp->tx_dma_chan = NULL;
+		qp->rx_dma_chan = NULL;
 	}
-	dev_dbg(&pdev->dev, "Using %s memcpy\n", qp->dma_chan ? "DMA" : "CPU");
+
+	dev_dbg(&pdev->dev, "Using %s memcpy for TX\n",
+		qp->tx_dma_chan ? "DMA" : "CPU");
+
+	dev_dbg(&pdev->dev, "Using %s memcpy for RX\n",
+		qp->rx_dma_chan ? "DMA" : "CPU");
 
 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
 		entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
@@ -1684,8 +1702,10 @@ err2:
 err1:
 	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);
+	if (qp->tx_dma_chan)
+		dma_release_channel(qp->tx_dma_chan);
+	if (qp->rx_dma_chan)
+		dma_release_channel(qp->rx_dma_chan);
 	nt->qp_bitmap_free |= qp_bit;
 err:
 	return NULL;
@@ -1709,12 +1729,27 @@ void ntb_transport_free_queue(struct ntb_transport_qp *qp)
 
 	pdev = qp->ndev->pdev;
 
-	if (qp->dma_chan) {
-		struct dma_chan *chan = qp->dma_chan;
+	if (qp->tx_dma_chan) {
+		struct dma_chan *chan = qp->tx_dma_chan;
+		/* Putting the dma_chan to NULL will force any new traffic to be
+		 * processed by the CPU instead of the DAM engine
+		 */
+		qp->tx_dma_chan = NULL;
+
+		/* Try to be nice and wait for any queued DMA engine
+		 * transactions to process before smashing it with a rock
+		 */
+		dma_sync_wait(chan, qp->last_cookie);
+		dmaengine_terminate_all(chan);
+		dma_release_channel(chan);
+	}
+
+	if (qp->rx_dma_chan) {
+		struct dma_chan *chan = qp->rx_dma_chan;
 		/* Putting the dma_chan to NULL will force any new traffic to be
 		 * processed by the CPU instead of the DAM engine
 		 */
-		qp->dma_chan = NULL;
+		qp->rx_dma_chan = NULL;
 
 		/* Try to be nice and wait for any queued DMA engine
 		 * transactions to process before smashing it with a rock
@@ -1962,16 +1997,20 @@ EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
 {
 	unsigned int max;
+	unsigned int copy_align;
 
 	if (!qp)
 		return 0;
 
-	if (!qp->dma_chan)
+	if (!qp->tx_dma_chan && !qp->rx_dma_chan)
 		return qp->tx_max_frame - sizeof(struct ntb_payload_header);
 
+	copy_align = max(qp->tx_dma_chan->device->copy_align,
+			 qp->rx_dma_chan->device->copy_align);
+
 	/* If DMA engine usage is possible, try to find the max size for that */
 	max = qp->tx_max_frame - sizeof(struct ntb_payload_header);
-	max -= max % (1 << qp->dma_chan->device->copy_align);
+	max -= max % (1 << copy_align);
 
 	return max;
 }
-- 
2.5.0.rc1