[dpdk-stable] [PATCH v2] net/ixgbe: fix link state timing issue on fiber ports

[Phil Yang <phil.yang@arm.com>]

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_thread_handler() is scheduled which should
try to set up the link and clear the flag afterwards. This flag works
as a guard variable between threads.

To avoid potential race condition between threads, set the
IXGBE_FLAG_NEED_LINK_CONFIG flag only when there is no link thread
running.

Fixes: 819d0d1d57f1 ("net/ixgbe: fix blocking system events")
Cc: stable@dpdk.org

Bugzilla ID: 388

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Lijian Zhang <lijian.zhang@arm.com>
---
v2:
1. rebase code.

 drivers/net/ixgbe/ixgbe_ethdev.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c b/drivers/net/ixgbe/ixgbe_ethdev.c
index aa1e8aa..dc19f0c 100644
--- a/drivers/net/ixgbe/ixgbe_ethdev.c
+++ b/drivers/net/ixgbe/ixgbe_ethdev.c
@@ -4276,9 +4276,13 @@ 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;
 			ixgbe_dev_wait_setup_link_complete(dev, 0);
 			if (rte_atomic32_test_and_set(&ad->link_thread_running)) {
+				/* To avoid race condition between threads, set
+				 * the IXGBE_FLAG_NEED_LINK_CONFIG flag only
+				 * when there is no link thread running.
+				 */
+				intr->flags |= IXGBE_FLAG_NEED_LINK_CONFIG;
 				if (rte_ctrl_thread_create(&ad->link_thread_tid,
 					"ixgbe-link-handler",
 					NULL,
-- 
2.7.4