From: Moti Haimovsky <motih@mellanox.com>
Date: Wed, 16 Oct 2019 07:34:03 +0000 (+0300)
Subject: net/mlx5: retry on link update failure
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=06ee15784871cc457d62b6c965bc8cdac40f9703;p=dpdk.git

net/mlx5: retry on link update failure

mlx5_link_update immediately returns when called with no-wait parameter
and its call for retrieving the link status returns with EAGAIN error.
This is too harsh on busy systems where a first call fails with EAGAIN
from time to time.
This patch adds a (very limited) retry on such cases in order to allow
retrieving the link status.

Signed-off-by: Moti Haimovsky <motih@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
---

diff --git a/drivers/net/mlx5/mlx5_defs.h b/drivers/net/mlx5/mlx5_defs.h
index 180122db6c..248ef3c8ac 100644
--- a/drivers/net/mlx5/mlx5_defs.h
+++ b/drivers/net/mlx5/mlx5_defs.h
@@ -105,6 +105,9 @@
 /* Timeout in seconds to get a valid link status. */
 #define MLX5_LINK_STATUS_TIMEOUT 10
 
+/* Number of times to retry retrieving the physical link information. */
+#define MLX5_GET_LINK_STATUS_RETRY_COUNT 3
+
 /* Maximum number of UAR pages used by a port,
  * These are the size and mask for an array of mutexes used to synchronize
  * the access to port's UARs on platforms that do not support 64 bit writes.
diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
index f2b17522cd..5f05b2bb50 100644
--- a/drivers/net/mlx5/mlx5_ethdev.c
+++ b/drivers/net/mlx5/mlx5_ethdev.c
@@ -999,6 +999,7 @@ mlx5_link_update(struct rte_eth_dev *dev, int wait_to_complete)
 	int ret;
 	struct rte_eth_link dev_link;
 	time_t start_time = time(NULL);
+	int retry = MLX5_GET_LINK_STATUS_RETRY_COUNT;
 
 	do {
 		ret = mlx5_link_update_unlocked_gs(dev, &dev_link);
@@ -1007,7 +1008,7 @@ mlx5_link_update(struct rte_eth_dev *dev, int wait_to_complete)
 		if (ret == 0)
 			break;
 		/* Handle wait to complete situation. */
-		if (wait_to_complete && ret == -EAGAIN) {
+		if ((wait_to_complete || retry) && ret == -EAGAIN) {
 			if (abs((int)difftime(time(NULL), start_time)) <
 			    MLX5_LINK_STATUS_TIMEOUT) {
 				usleep(0);
@@ -1019,7 +1020,7 @@ mlx5_link_update(struct rte_eth_dev *dev, int wait_to_complete)
 		} else if (ret < 0) {
 			return ret;
 		}
-	} while (wait_to_complete);
+	} while (wait_to_complete || retry-- > 0);
 	ret = !!memcmp(&dev->data->dev_link, &dev_link,
 		       sizeof(struct rte_eth_link));
 	dev->data->dev_link = dev_link;