dpdk: false link down issue with ixgbe NIC

This issue is observed with X520-2 NICs on FD.io lab Taishan server.
After VPP booting up and bringing up  the interfaces with command "set
interface state <interface> up", it still shows link down status from
the command "show hardware-interfaces". However, the hardware link
status is actually up. dpdk_process() cannot get the hardware link
status correctly via rte_eth_link_get_nowait().

In ixgbe_dev_link_update_share(), if the media type is fiber and the
link is down, a flag (IXGBE_FLAG_NEED_LINK_CONFIG) is set. A callback to
ixgbe_dev_setup_link_alarm_handler() is scheduled trying to set up the
link and clear the flag afterwards.

If the device is started or stopped before the flag is cleared, the
scheduled callback is canceled. This causes the flag to remain set and
subsequent calls to ixgbe_dev_link_update_share() return without trying
to retrieve the link state because the flag is set.

When the callback is canceled by either interface start or stop
operation, in ixgbe_dev_cancel_link_thread(), after cancelling the
callback/thread, unset the flag on the device to avoid this condition.

Type: fix

Signed-off-by: Lijian Zhang <Lijian.Zhang@arm.com>
Reviewed-by: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
Reviewed-by: Jieqiang Wang <Jieqiang.Wang@arm.com>
Change-Id: I04de377dc048307a78a5b7109ebdfaf376d5e029

1 files changed, 66 insertions, 0 deletions

diff --git a/build/external/patches/dpdk_20.02/0001-ixgbe-fix-false-link-down-timing-issue.patch b/build/external/patches/dpdk_20.02/0001-ixgbe-fix-false-link-down-timing-issue.patch
new file mode 100644
index 00000000000..6e0627b0338
--- /dev/null
+++ b/build/external/patches/dpdk_20.02/0001-ixgbe-fix-false-link-down-timing-issue.patch
@@ -0,0 +1,66 @@
+From 6033eeec2b029d99d4c0e46065f311fbbb2a1f1b Mon Sep 17 00:00:00 2001
+From: Lijian Zhang <Lijian.Zhang@arm.com>
+Date: Wed, 18 Mar 2020 17:21:08 +0800
+Subject: [PATCH] ixgbe: fix false link down timing issue
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This issue is observed with X520-2 NICs on FD.io Taishan server. After
+VPP booting up and bringing up the interfaces with command ‘set
+interface state <interface> up’, it still shows link down status from
+the command ‘show hardware-interfaces’. However, the hardware link
+status is actually up. dpdk_process() cannot get the hardware link
+status correctly via rte_eth_link_get_nowait().
+
+In ixgbe_dev_link_update_share(), if the media type is fiber and the
+link is down, a flag (IXGBE_FLAG_NEED_LINK_CONFIG) is set. A callback to
+ixgbe_dev_setup_link_alarm_handler() is scheduled trying to set up the
+link and clear the flag afterwards.
+
+If the device is started or stopped before the flag is cleared, the
+scheduled callback is canceled. This causes the flag to remain set and
+subsequent calls to ixgbe_dev_link_update_share() return without trying
+to retrieve the link state because the flag is set.
+
+When the callback is canceled by either interface start or stop
+operation, in ixgbe_dev_cancel_link_thread(), after cancelling the
+callback/thread, unset the flag on the device to avoid this condition.
+
+Signed-off-by: Lijian Zhang <Lijian.Zhang@arm.com>
+---
+ drivers/net/ixgbe/ixgbe_ethdev.c | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c b/drivers/net/ixgbe/ixgbe_ethdev.c
+index 23b3f5b0c..aa882cb8b 100644
+--- a/drivers/net/ixgbe/ixgbe_ethdev.c
++++ b/drivers/net/ixgbe/ixgbe_ethdev.c
+@@ -4147,11 +4147,14 @@ static void
+ ixgbe_dev_cancel_link_thread(struct rte_eth_dev *dev)
+ {
+ 	struct ixgbe_adapter *ad = dev->data->dev_private;
++	struct ixgbe_interrupt *intr =
++		IXGBE_DEV_PRIVATE_TO_INTR(dev->data->dev_private);
+ 	void *retval;
+ 
+ 	if (rte_atomic32_read(&ad->link_thread_running)) {
+ 		pthread_cancel(ad->link_thread_tid);
+ 		pthread_join(ad->link_thread_tid, &retval);
++		intr->flags &= ~IXGBE_FLAG_NEED_LINK_CONFIG;
+ 		rte_atomic32_clear(&ad->link_thread_running);
+ 	}
+ }
+@@ -4262,8 +4265,8 @@ ixgbe_dev_link_update_share(struct rte_eth_dev *dev,
+ 
+ 	if (link_up == 0) {
+ 		if (ixgbe_get_media_type(hw) == ixgbe_media_type_fiber) {
+-			intr->flags |= IXGBE_FLAG_NEED_LINK_CONFIG;
+ 			if (rte_atomic32_test_and_set(&ad->link_thread_running)) {
++				intr->flags |= IXGBE_FLAG_NEED_LINK_CONFIG;
+ 				if (rte_ctrl_thread_create(&ad->link_thread_tid,
+ 					"ixgbe-link-handler",
+ 					NULL,
+-- 
+2.17.1
+