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NTB: Performance and bug fixes in ntb drivers

PATCH Superseded Allen Hubbe 2 participants 17 messages Jul 6, 2015 – Jul 13, 2015

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#0 lore raw

cover NTB: Performance and bug fixes in ntb drivers

This series includes the following changes to fix bugs, add new hardware support, and improve usability and performance of the ntb drivers.

Bug Fixes (issues preexisting the new ntb api):
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: ntb_netdev not covering all receive errors
NTB: Fix oops in debugfs when transport is half-up

Bug Fixes (regressions since the new ntb api):
NTB: Fix transport stats for multiple devices

Additions and Performance Improvements:
NTB: Remove dma_sync_wait from ntb_async_rx
NTB: Add PCI Device IDs for Broadwell Xeon
NTB: Add flow control to the ntb_netdev
NTB: Make the transport list in order of discovery
NTB: Clean up QP stats info
NTB: Use unique DMA channels for TX and RX

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

Dave Jiang (8):
NTB: Add flow control to the ntb_netdev
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
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

 drivers/net/ntb_netdev.c            |  89 +++++++++-
 drivers/ntb/hw/intel/ntb_hw_intel.c |  15 ++
 drivers/ntb/hw/intel/ntb_hw_intel.h |   3 +
 drivers/ntb/ntb_transport.c         | 322 ++++++++++++++++++++++++------------
 include/linux/ntb_transport.h       |   1 +
 5 files changed, 320 insertions(+), 110 deletions(-)
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#1 lore raw

PATCH 1/12 NTB: Fix ntb_transport out-of-order RX update

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.

---
 drivers/net/ntb_netdev.c    |   7 ++
 drivers/ntb/ntb_transport.c | 169 ++++++++++++++++++++++++++------------------
 2 files changed, 107 insertions(+), 69 deletions(-)
drivers/net/ntb_netdev.c +7 -0
index 3cc316cb7e6b..5f1ee7c05f68 100644
@@ -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);
drivers/ntb/ntb_transport.c +100 -69

300 lines not on this page · raw message

Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#2 lore raw

PATCH 2/12 NTB: Add flow control to the ntb_netdev

In reply to Allen Hubbe

From: Dave Jiang <[email protected]>

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 stop 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.

The following module parameters are added:
tx_time: The time in usecs for us to wait before we check if we restart
transmit queue. (default: 1)
tx_start: The number of descriptors we wait for to free up before resuming
transmit queue. (default: 10)
tx_stop: The low water mark of free descriptors before we stop tx queue.

	 (default: 5)
---
 drivers/net/ntb_netdev.c      | 80 +++++++++++++++++++++++++++++++++++++++++++
 drivers/ntb/ntb_transport.c   | 18 +++++++++-
 include/linux/ntb_transport.h |  1 +
 3 files changed, 98 insertions(+), 1 deletion(-)
drivers/net/ntb_netdev.c +80 -0
index 5f1ee7c05f68..84d094df1a63 100644
@@ -61,11 +61,24 @@ MODULE_VERSION(NTB_NETDEV_VER);
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Intel Corporation");
 
+static unsigned int tx_time = 1;
+module_param(tx_time, uint, 0644);
+MODULE_PARM_DESC(tx_time, "Time in usecs for tx resource reaper");
+
+static unsigned int tx_start = 10;
+module_param(tx_start, uint, 0644);
+MODULE_PARM_DESC(tx_start, "Number of descriptors to free before resume tx");
+
+static unsigned int tx_stop = 5;
+module_param(tx_stop, uint, 0644);
+MODULE_PARM_DESC(tx_stop, "Number of descriptors before stop upper layer tx");
+
 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 +149,42 @@ 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 +199,15 @@ 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 +216,15 @@ 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 +233,23 @@ 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 +272,11 @@ 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 +297,8 @@ 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;
 }
 
drivers/ntb/ntb_transport.c +17 -1
index 98e58c765f2e..76a03d4070a9 100644
@@ -488,6 +488,12 @@ 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",
@@ -529,6 +535,7 @@ 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);
 
@@ -1827,7 +1834,7 @@ 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;
@@ -1953,6 +1960,15 @@ 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;
include/linux/ntb_transport.h +1 -0
index 2862861366a5..7243eb98a722 100644
@@ -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);
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
maintainer
#3 lore raw

Re: [PATCH 02/12] NTB: Add flow control to the ntb_netdev

Quoted 36 lines · Allen Hubbe

From: Dave Jiang <[email protected]>

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 stop 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.

The following module parameters are added:
tx_time: The time in usecs for us to wait before we check if we restart
transmit queue. (default: 1)
tx_start: The number of descriptors we wait for to free up before resuming
transmit queue. (default: 10)
tx_stop: The low water mark of free descriptors before we stop tx queue.

         (default: 5)
---
 drivers/net/ntb_netdev.c      | 80 +++++++++++++++++++++++++++++++++++++++++++
 drivers/ntb/ntb_transport.c   | 18 +++++++++-
 include/linux/ntb_transport.h |  1 +
 3 files changed, 98 insertions(+), 1 deletion(-)
drivers/net/ntb_netdev.c +1 -0
index 5f1ee7c05f68..84d094df1a63 100644
@@ -61,11 +61,24 @@ MODULE_VERSION(NTB_NETDEV_VER);
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Intel Corporation");
 
+static unsigned int tx_time = 1;

drivers/net/ntb_netdev.c MODULE_VERSION(NTB_NETDEV_VER); · line 74

Quoted 10 lines
drivers/net/ntb_netdev.c +10 -0
+module_param(tx_time, uint, 0644);
+MODULE_PARM_DESC(tx_time, "Time in usecs for tx resource reaper");
+
+static unsigned int tx_start = 10;
+module_param(tx_start, uint, 0644);
+MODULE_PARM_DESC(tx_start, "Number of descriptors to free before resume tx");
+
+static unsigned int tx_stop = 5;
+module_param(tx_stop, uint, 0644);
+MODULE_PARM_DESC(tx_stop, "Number of descriptors before stop upper layer tx");

Do you really see these being used outside of development for finetuning performance? If not, the let's remove these and just mod them by hand when perf tuning. There is no use adding knobs that no one in the field will ever use (assuming I am correct, and no one will ever change these from the defaults).

Aside that that, it looks fine.

Quoted 197 lines
drivers/net/ntb_netdev.c +68 -0
 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 +149,42 @@ 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 +199,15 @@ 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 +216,15 @@ 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 +233,23 @@ 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 +272,11 @@ 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 +297,8 @@ 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;
 }
 
drivers/ntb/ntb_transport.c +17 -1
index 98e58c765f2e..76a03d4070a9 100644
@@ -488,6 +488,12 @@ 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",
@@ -529,6 +535,7 @@ 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);
 
@@ -1827,7 +1834,7 @@ 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;
@@ -1953,6 +1960,15 @@ 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;
include/linux/ntb_transport.h +1 -1
index 2862861366a5..7243eb98a722 100644
@@ -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);
--

2.4.0.rc0.43.gcf8a8c6

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#4 lore raw

RE: [PATCH 02/12] NTB: Add flow control to the ntb_netdev

From: Jon Mason

Quoted 14 lines

drivers/net/ntb_netdev.c MODULE_VERSION(NTB_NETDEV_VER);

Quoted 7 lines
drivers/net/ntb_netdev.c +7 -0
+static unsigned int tx_time = 1;
+module_param(tx_time, uint, 0644);
+MODULE_PARM_DESC(tx_time, "Time in usecs for tx resource reaper");
+
+static unsigned int tx_start = 10;
+module_param(tx_start, uint, 0644);
+MODULE_PARM_DESC(tx_start, "Number of descriptors to free before

resume tx");

drivers/net/ntb_netdev.c MODULE_VERSION(NTB_NETDEV_VER);

Quoted 4 lines
drivers/net/ntb_netdev.c +4 -0
+
+static unsigned int tx_stop = 5;
+module_param(tx_stop, uint, 0644);
+MODULE_PARM_DESC(tx_stop, "Number of descriptors before stop upper

layer tx");

Quoted 5 lines

Do you really see these being used outside of development for finetuning performance? If not, the let's remove these and just mod them by hand when perf tuning. There is no use adding knobs that no one in the field will ever use (assuming I am correct, and no one will ever change these from the defaults).

I think you are right that the parameters will never be changed away from their defaults, and it would be easy enough to add the parameters back if it is requested. I would be ok with removing them, contrary to my request to add them.

I asked to add the parameters, thinking that a different tuning might be desirable depending on the workload and link characteristics. A high frame rate will recoup credits faster than a slow frame rate. The frame rate depends on the frame size (eg, transactional vs throughput workload), and the speed of the link (eg, PCIe generation and width). I think we could observe an order of magnitude difference in frame rate with different workloads on different links.

To determine the default setting, I suggested that we run a small frame workload, and tune for the longest delay that does not affect response time, and then validate the setting by running a large frame workload. If the extra timer expirations don't impact cpu utilization too much with the large frame workload, then the parameters might be entirely unnecessary. I should have also requested to cut the link width in half for the large frame workload, so we could observe a greater effect.

#5 lore raw

PATCH 3/12 NTB: Fix transport stats for multiple devices

In reply to Allen Hubbe

From: Dave Jiang <[email protected]>

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.

---
 drivers/ntb/ntb_transport.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)
drivers/ntb/ntb_transport.c +10 -2
index 76a03d4070a9..7e2de6764b9f 100644
@@ -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 {
@@ -952,12 +954,12 @@ 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,
@@ -1060,6 +1062,12 @@ 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)
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#6 lore raw

PATCH 4/12 NTB: ntb_netdev not covering all receive errors

In reply to Allen Hubbe

From: Dave Jiang <[email protected]>

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.

---
 drivers/net/ntb_netdev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/net/ntb_netdev.c +1 -1
index 84d094df1a63..e7072e544567 100644
@@ -266,7 +266,7 @@ 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;
 		}
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#7 lore raw

PATCH 5/12 NTB: Fix oops in debugfs when transport is half-up

In reply to Allen Hubbe

From: Dave Jiang <[email protected]>

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.

---
 drivers/ntb/ntb_transport.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
drivers/ntb/ntb_transport.c +5 -1
index 7e2de6764b9f..73bb58bbcaec 100644
@@ -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");
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#8 lore raw

PATCH 6/12 NTB: Schedule to receive on QP link up

In reply to Allen Hubbe

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

---
 drivers/ntb/ntb_transport.c | 2 ++
 1 file changed, 2 insertions(+)
drivers/ntb/ntb_transport.c +2 -0
index 73bb58bbcaec..4bba3c4a4a3a 100644
@@ -902,6 +902,8 @@ 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));
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#9 lore raw

PATCH 7/12 NTB: Add PCI Device IDs for Broadwell Xeon

In reply to Allen Hubbe

From: Dave Jiang <[email protected]>

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

---
 drivers/ntb/hw/intel/ntb_hw_intel.c | 15 +++++++++++++++
 drivers/ntb/hw/intel/ntb_hw_intel.h |  3 +++
 2 files changed, 18 insertions(+)
drivers/ntb/hw/intel/ntb_hw_intel.c +15 -0
index 87751cfd6f4f..c2bc56b67e63 100644
@@ -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);
drivers/ntb/hw/intel/ntb_hw_intel.h +3 -0
index 7ddaf387b679..ea0612f797df 100644
@@ -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 */
 
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#10 lore raw

PATCH 8/12 NTB: Make the transport list in order of discovery

In reply to Allen Hubbe

From: Dave Jiang <[email protected]>

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.

---
 drivers/ntb/ntb_transport.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/ntb/ntb_transport.c +1 -1
index 4bba3c4a4a3a..f92239141674 100644
@@ -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;
 }
 
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#11 lore raw

PATCH 9/12 NTB: Clean up QP stats info

In reply to Allen Hubbe

From: Dave Jiang <[email protected]>

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

---
 drivers/ntb/ntb_transport.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)
drivers/ntb/ntb_transport.c +16 -9
index f92239141674..98ecf6d50621 100644
@@ -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;
 
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#12 lore raw

PATCH 10/12 NTB: Remove dma_sync_wait from ntb_async_rx

In reply to 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.

---
 drivers/ntb/ntb_transport.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)
drivers/ntb/ntb_transport.c +3 -9
index 98ecf6d50621..dd4e3ab824aa 100644
@@ -1230,18 +1230,18 @@ 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),
@@ -1284,12 +1284,6 @@ 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++;
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#13 lore raw

PATCH 11/12 NTB: Use unique DMA channels for TX and RX

In reply to Allen Hubbe

From: Dave Jiang <[email protected]>

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.

---
 drivers/ntb/ntb_transport.c | 77 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 58 insertions(+), 19 deletions(-)
drivers/ntb/ntb_transport.c +58 -19
index dd4e3ab824aa..fbddeab13b4c 100644
@@ -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");
@@ -1217,7 +1222,7 @@ 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;
@@ -1378,8 +1383,8 @@ 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 */
@@ -1446,7 +1451,7 @@ 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;
@@ -1639,14 +1644,27 @@ 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);
@@ -1681,8 +1699,10 @@ 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;
@@ -1707,12 +1727,27 @@ 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
@@ -1960,16 +1995,20 @@ 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;
 }
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
#14 lore raw

PATCH 12/12 NTB: Fix zero size or integer overflow in ntb_set_mw

In reply to 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.

---
 drivers/ntb/ntb_transport.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
drivers/ntb/ntb_transport.c +6 -3
index fbddeab13b4c..42ae5a122412 100644
@@ -648,13 +648,16 @@ 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);
 
@@ -674,7 +677,7 @@ 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;
 	}
Signature · 1 line
2.4.0.rc0.43.gcf8a8c6
maintainer
#15 lore raw
In reply to Allen Hubbe
Quoted 13 lines · Allen Hubbe

This series includes the following changes to fix bugs, add new hardware support, and improve usability and performance of the ntb drivers.

Bug Fixes (issues preexisting the new ntb api):
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: ntb_netdev not covering all receive errors
NTB: Fix oops in debugfs when transport is half-up

Bug Fixes (regressions since the new ntb api):
NTB: Fix transport stats for multiple devices

Quoted 8 lines

Additions and Performance Improvements:
NTB: Remove dma_sync_wait from ntb_async_rx
NTB: Add PCI Device IDs for Broadwell Xeon
NTB: Add flow control to the ntb_netdev
NTB: Make the transport list in order of discovery
NTB: Clean up QP stats info
NTB: Use unique DMA channels for TX and RX

Ignoring the outstanding quesiton on patch 2, these patches look acceptable.

For clarity, patches 1, 2, and 4 are bug fixes and can be sent to Linus now. Patches 3, 5, 6, 9 and 10 look to be features, and should hit the next merge window. How would you like patches 7, 8, and/or 12 handled?

Thanks,
Jon

Quoted 26 lines

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

Dave Jiang (8):
NTB: Add flow control to the ntb_netdev
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
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

 drivers/net/ntb_netdev.c            |  89 +++++++++-
 drivers/ntb/hw/intel/ntb_hw_intel.c |  15 ++
 drivers/ntb/hw/intel/ntb_hw_intel.h |   3 +
 drivers/ntb/ntb_transport.c         | 322 ++++++++++++++++++++++++------------
 include/linux/ntb_transport.h       |   1 +
 5 files changed, 320 insertions(+), 110 deletions(-)

--
2.4.0.rc0.43.gcf8a8c6

#16 lore raw

I rearranged patches in github into bug fixes and features.

Bug fixes are in ntb-abh.
https://github.com/allenbh/linux/commits/ntb-abh

Features are in ntb-abh-next, after the bug fixes, and the patch to add the email list to MAINTAINERS.
https://github.com/allenbh/linux/commits/ntb-abh-next

Quoted 4 lines

Ignoring the outstanding quesiton on patch 2, these patches look acceptable.

For clarity, patches 1, 2, and 4 are bug fixes and can be sent to

Patch 2 is _not_ a bug fix.

Quoted 1 line

Linus now. Patches 3, 5, 6, 9 and 10 look to be features, and should

Patch 3 fixes a regression - affecting debugfs users only.

Patch 5 is a bug fix.

Patch 6 is perhaps a bug fix, though we have not seen any breakage. I suspected this could be the reason for a link not coming up, but there was a different cause for that issue.

Patch 9 is a feature.

Patch 10 is a feature.

Quoted 2 lines

hit the next merge window. How would you like patches 7, 8, and/or 12 handled?

Patch 7 is a feature.

Patch 8 is a feature; it could be argued a bug fix because it fixes a usability issue.

Patch 12 is a bug fix, and it fixes an issue that we have observed in the wild. The bug is not a regression.

Quoted 33 lines

Thanks,
Jon

Quoted 16 lines

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

Dave Jiang (8):
NTB: Add flow control to the ntb_netdev
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
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

Quoted 4 lines
 drivers/net/ntb_netdev.c            |  89 +++++++++-
 drivers/ntb/hw/intel/ntb_hw_intel.c |  15 ++
 drivers/ntb/hw/intel/ntb_hw_intel.h |   3 +
 drivers/ntb/ntb_transport.c         | 322 ++++++++++++++++++++++++---

---------

Quoted 6 lines
 include/linux/ntb_transport.h       |   1 +
 5 files changed, 320 insertions(+), 110 deletions(-)

--
2.4.0.rc0.43.gcf8a8c6