[dpdk-stable] patch 'event/dsw: avoid credit leak on oversized enqueue bursts' has been queued to LTS release 18.11.7

[Kevin Traynor <ktraynor@redhat.com>]

Hi,

FYI, your patch has been queued to LTS release 18.11.7

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 02/13/20. 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. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/kevintraynor/dpdk-stable-queue

This queued commit can be viewed at:
https://github.com/kevintraynor/dpdk-stable-queue/commit/1caa6035fa2a96f7de79d24d15b07b6f598d1697

Thanks.

Kevin.

---
From 1caa6035fa2a96f7de79d24d15b07b6f598d1697 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mattias=20R=C3=B6nnblom?= <mattias.ronnblom@ericsson.com>
Date: Tue, 14 Jan 2020 19:03:38 +0100
Subject: [PATCH] event/dsw: avoid credit leak on oversized enqueue bursts
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

[ upstream commit 0c4155c7b5b51a60f676c1d7279bfcd1b14acd38 ]

If an application issues rte_event_enqueue_new_burst() or
rte_event_enqueue_forward_burst() call with a burst of events longer
than the configured max enqueue burst size, DSW allocates credits not
only for events actually enqueued, but for the complete burst. If this
process is repeated, enough credits will have leaked to cause the
event device to backpressure (i.e. disallow) any new enqueue
operations.

In addition, the port-level enqueue xstats will log the wrong number
of events enqueued for oversized enqueues.

This patch makes DSW gracefully handle oversized enqueue bursts.

Fixes: 1c8e3caa3bfb ("event/dsw: add event scheduling and device start/stop")

Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
---
 drivers/event/dsw/dsw_event.c | 38 ++++++++++++++++++++++++-----------
 1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/drivers/event/dsw/dsw_event.c b/drivers/event/dsw/dsw_event.c
index 1641c2d06e..eae53b2404 100644
--- a/drivers/event/dsw/dsw_event.c
+++ b/drivers/event/dsw/dsw_event.c
@@ -1019,10 +1019,10 @@ dsw_event_enqueue(void *port, const struct rte_event *ev)
 
 static __rte_always_inline uint16_t
-dsw_event_enqueue_burst_generic(void *port, const struct rte_event events[],
+dsw_event_enqueue_burst_generic(struct dsw_port *source_port,
+				const struct rte_event events[],
 				uint16_t events_len, bool op_types_known,
 				uint16_t num_new, uint16_t num_release,
 				uint16_t num_non_release)
 {
-	struct dsw_port *source_port = port;
 	struct dsw_evdev *dsw = source_port->dsw;
 	bool enough_credits;
@@ -1048,11 +1048,8 @@ dsw_event_enqueue_burst_generic(void *port, const struct rte_event events[],
 	if (unlikely(events_len == 0)) {
 		dsw_port_note_op(source_port, DSW_MAX_PORT_OPS_PER_BG_TASK);
-		dsw_port_flush_out_buffers(dsw, port);
+		dsw_port_flush_out_buffers(dsw, source_port);
 		return 0;
 	}
 
-	if (unlikely(events_len > source_port->enqueue_depth))
-		events_len = source_port->enqueue_depth;
-
 	dsw_port_note_op(source_port, events_len);
 
@@ -1110,6 +1107,11 @@ dsw_event_enqueue_burst(void *port, const struct rte_event events[],
 			uint16_t events_len)
 {
-	return dsw_event_enqueue_burst_generic(port, events, events_len, false,
-					       0, 0, 0);
+	struct dsw_port *source_port = port;
+
+	if (unlikely(events_len > source_port->enqueue_depth))
+		events_len = source_port->enqueue_depth;
+
+	return dsw_event_enqueue_burst_generic(source_port, events,
+					       events_len, false, 0, 0, 0);
 }
 
@@ -1118,6 +1120,12 @@ dsw_event_enqueue_new_burst(void *port, const struct rte_event events[],
 			    uint16_t events_len)
 {
-	return dsw_event_enqueue_burst_generic(port, events, events_len, true,
-					       events_len, 0, events_len);
+	struct dsw_port *source_port = port;
+
+	if (unlikely(events_len > source_port->enqueue_depth))
+		events_len = source_port->enqueue_depth;
+
+	return dsw_event_enqueue_burst_generic(source_port, events,
+					       events_len, true, events_len,
+					       0, events_len);
 }
 
@@ -1126,6 +1134,12 @@ dsw_event_enqueue_forward_burst(void *port, const struct rte_event events[],
 				uint16_t events_len)
 {
-	return dsw_event_enqueue_burst_generic(port, events, events_len, true,
-					       0, 0, events_len);
+	struct dsw_port *source_port = port;
+
+	if (unlikely(events_len > source_port->enqueue_depth))
+		events_len = source_port->enqueue_depth;
+
+	return dsw_event_enqueue_burst_generic(source_port, events,
+					       events_len, true, 0, 0,
+					       events_len);
 }
 
-- 
2.21.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2020-02-07 15:08:18.054801011 +0000
+++ 0010-event-dsw-avoid-credit-leak-on-oversized-enqueue-bur.patch	2020-02-07 15:08:17.495063202 +0000
@@ -1 +1 @@
-From 0c4155c7b5b51a60f676c1d7279bfcd1b14acd38 Mon Sep 17 00:00:00 2001
+From 1caa6035fa2a96f7de79d24d15b07b6f598d1697 Mon Sep 17 00:00:00 2001
@@ -8,0 +9,2 @@
+[ upstream commit 0c4155c7b5b51a60f676c1d7279bfcd1b14acd38 ]
+
@@ -23 +24,0 @@
-Cc: stable@dpdk.org