[dpdk-stable] patch 'net/netvsc: resize event buffer as needed' has been queued to stable release 18.08.1

[Kevin Traynor]

Hi,

FYI, your patch has been queued to stable release 18.08.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 11/23/18. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the patch applied
to the branch. If the code is different (ie: not only metadata diffs), due for example to
a change in context or macro names, please double check it.

Thanks.

Kevin Traynor

---
>From 9b56b30a66a8005f3eba80dd953d2d388a88fa44 Mon Sep 17 00:00:00 2001
From: Stephen Hemminger <sthemmin at microsoft.com>
Date: Tue, 14 Aug 2018 09:45:25 -0700
Subject: [PATCH] net/netvsc: resize event buffer as needed

[ upstream commit 1f2766b7ee02c434b554513193c2a2be6664601d ]

The event buffer was changed to be a fixed size value,
had a couple of issues. The big one is that rte_free was still
being called for a pointer that was not setup with rte_malloc().

The event buffer was also too small to handle heavy receive
traffic; and running the event buffer out would crash
the application.

Fix by going back to a dynamically resized event buffer.
And grow it by 25% to avoid lots of realloc's.

Fixes: 530af95a7849 ("bus/vmbus: avoid signalling host on read")

Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com>
---
 drivers/net/netvsc/hn_rxtx.c | 50 ++++++++++++++++++++++++++----------
 drivers/net/netvsc/hn_var.h  |  2 +-
 2 files changed, 38 insertions(+), 14 deletions(-)

diff --git a/drivers/net/netvsc/hn_rxtx.c b/drivers/net/netvsc/hn_rxtx.c
index 02ef27e36..9b394d261 100644
--- a/drivers/net/netvsc/hn_rxtx.c
+++ b/drivers/net/netvsc/hn_rxtx.c
@@ -11,4 +11,5 @@
 #include <unistd.h>
 #include <strings.h>
+#include <malloc.h>
 
 #include <rte_ethdev.h>
@@ -719,14 +720,22 @@ struct hn_rx_queue *hn_rx_queue_alloc(struct hn_data *hv,
 	struct hn_rx_queue *rxq;
 
-	rxq = rte_zmalloc_socket("HN_RXQ",
-				 sizeof(*rxq) + HN_RXQ_EVENT_DEFAULT,
+	rxq = rte_zmalloc_socket("HN_RXQ", sizeof(*rxq),
 				 RTE_CACHE_LINE_SIZE, socket_id);
-	if (rxq) {
-		rxq->hv = hv;
-		rxq->chan = hv->channels[queue_id];
-		rte_spinlock_init(&rxq->ring_lock);
-		rxq->port_id = hv->port_id;
-		rxq->queue_id = queue_id;
+	if (!rxq)
+		return NULL;
+
+	rxq->hv = hv;
+	rxq->chan = hv->channels[queue_id];
+	rte_spinlock_init(&rxq->ring_lock);
+	rxq->port_id = hv->port_id;
+	rxq->queue_id = queue_id;
+	rxq->event_sz = HN_RXQ_EVENT_DEFAULT;
+	rxq->event_buf = rte_malloc_socket("HN_EVENTS", HN_RXQ_EVENT_DEFAULT,
+					   RTE_CACHE_LINE_SIZE, socket_id);
+	if (!rxq->event_buf) {
+		rte_free(rxq);
+		return NULL;
 	}
+
 	return rxq;
 }
@@ -854,17 +863,32 @@ void hn_process_events(struct hn_data *hv, uint16_t queue_id)
 	for (;;) {
 		const struct vmbus_chanpkt_hdr *pkt;
-		uint32_t len = HN_RXQ_EVENT_DEFAULT;
+		uint32_t len = rxq->event_sz;
 		const void *data;
 
+retry:
 		ret = rte_vmbus_chan_recv_raw(rxq->chan, rxq->event_buf, &len);
 		if (ret == -EAGAIN)
 			break;	/* ring is empty */
 
-		else if (ret == -ENOBUFS)
-			rte_exit(EXIT_FAILURE, "event buffer not big enough (%u < %u)",
-				 HN_RXQ_EVENT_DEFAULT, len);
-		else if (ret <= 0)
+		if (unlikely(ret == -ENOBUFS)) {
+			/* event buffer not large enough to read ring */
+
+			PMD_DRV_LOG(DEBUG,
+				    "event buffer expansion (need %u)", len);
+			rxq->event_sz = len + len / 4;
+			rxq->event_buf = rte_realloc(rxq->event_buf, rxq->event_sz,
+						     RTE_CACHE_LINE_SIZE);
+			if (rxq->event_buf)
+				goto retry;
+			/* out of memory, no more events now */
+			rxq->event_sz = 0;
+			break;
+		}
+
+		if (unlikely(ret <= 0)) {
+			/* This indicates a failure to communicate (or worse) */
 			rte_exit(EXIT_FAILURE,
 				 "vmbus ring buffer error: %d", ret);
+		}
 
 		bytes_read += ret;
diff --git a/drivers/net/netvsc/hn_var.h b/drivers/net/netvsc/hn_var.h
index f7ff8585b..0430f450c 100644
--- a/drivers/net/netvsc/hn_var.h
+++ b/drivers/net/netvsc/hn_var.h
@@ -78,5 +78,5 @@ struct hn_rx_queue {
 	uint64_t ring_full;
 
-	uint8_t	event_buf[];
+	void *event_buf;
 };
 
-- 
2.19.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2018-11-20 17:53:07.687552366 +0000
+++ 0009-net-netvsc-resize-event-buffer-as-needed.patch	2018-11-20 17:53:07.000000000 +0000
@@ -1,8 +1,10 @@
-From 1f2766b7ee02c434b554513193c2a2be6664601d Mon Sep 17 00:00:00 2001
+From 9b56b30a66a8005f3eba80dd953d2d388a88fa44 Mon Sep 17 00:00:00 2001
 From: Stephen Hemminger <sthemmin at microsoft.com>
 Date: Tue, 14 Aug 2018 09:45:25 -0700
 Subject: [PATCH] net/netvsc: resize event buffer as needed
 
+[ upstream commit 1f2766b7ee02c434b554513193c2a2be6664601d ]
+
 The event buffer was changed to be a fixed size value,
 had a couple of issues. The big one is that rte_free was still
 being called for a pointer that was not setup with rte_malloc().
@@ -15,7 +17,6 @@
 And grow it by 25% to avoid lots of realloc's.
 
 Fixes: 530af95a7849 ("bus/vmbus: avoid signalling host on read")
-Cc: stable at dpdk.org
 
 Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com>
 ---
@@ -24,7 +25,7 @@
  2 files changed, 38 insertions(+), 14 deletions(-)
 
 diff --git a/drivers/net/netvsc/hn_rxtx.c b/drivers/net/netvsc/hn_rxtx.c
-index 24abc2a91..cb5bc6029 100644
+index 02ef27e36..9b394d261 100644
 --- a/drivers/net/netvsc/hn_rxtx.c
 +++ b/drivers/net/netvsc/hn_rxtx.c
 @@ -11,4 +11,5 @@
@@ -64,7 +65,7 @@
 +
  	return rxq;
  }
-@@ -864,17 +873,32 @@ uint32_t hn_process_events(struct hn_data *hv, uint16_t queue_id,
+@@ -854,17 +863,32 @@ void hn_process_events(struct hn_data *hv, uint16_t queue_id)
  	for (;;) {
  		const struct vmbus_chanpkt_hdr *pkt;
 -		uint32_t len = HN_RXQ_EVENT_DEFAULT;
@@ -103,10 +104,10 @@
  
  		bytes_read += ret;
 diff --git a/drivers/net/netvsc/hn_var.h b/drivers/net/netvsc/hn_var.h
-index fec8d7c40..b42bd97b9 100644
+index f7ff8585b..0430f450c 100644
 --- a/drivers/net/netvsc/hn_var.h
 +++ b/drivers/net/netvsc/hn_var.h
-@@ -81,5 +81,5 @@ struct hn_rx_queue {
+@@ -78,5 +78,5 @@ struct hn_rx_queue {
  	uint64_t ring_full;
  
 -	uint8_t	event_buf[];