[dpdk-dev] [PATCH 1/2] ixgbe: fix VF statistic wraparound handling macro

[Harry van Haaren]

Fix a misinterpretation of VF stats in ixgbe

Signed-off-by: Harry van Haaren <harry.van.haaren at intel.com>
---
 drivers/net/ixgbe/ixgbe_ethdev.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c b/drivers/net/ixgbe/ixgbe_ethdev.c
index ec2918c..d226e8d 100644
--- a/drivers/net/ixgbe/ixgbe_ethdev.c
+++ b/drivers/net/ixgbe/ixgbe_ethdev.c
@@ -329,10 +329,14 @@ static int ixgbe_timesync_read_tx_timestamp(struct rte_eth_dev *dev,
 /*
  * Define VF Stats MACRO for Non "cleared on read" register
  */
-#define UPDATE_VF_STAT(reg, last, cur)	                        \
+#define UPDATE_VF_STAT(reg, last, cur)                          \
 {                                                               \
 	uint32_t latest = IXGBE_READ_REG(hw, reg);              \
-	cur += latest - last;                                   \
+	if(likely(latest > last)) {                             \
+		cur += latest - last;                           \
+	} else {                                                \
+		cur += (UINT_MAX - last) + latest;              \
+	}                                                       \
 	last = latest;                                          \
 }
 
-- 
1.9.1