[dpdk-stable] [PATCH v2 1/2] net/ixgbe: fix defects of macro in VF

[Guinan Sun <guinanx.sun@intel.com>]

The defects in the macros UPDATE_VF_STAT and UPDATE_VF_STAT_36BIT exist.
If latest is less than last, we will get wrong result.
The patch fixes the defect.

Fixes: abf7275bbaa2 ("ixgbe: move to drivers/net/")
Cc: stable@dpdk.org

Signed-off-by: Guinan Sun <guinanx.sun@intel.com>
---
v2 changes:
* Aligned line-continuation character "\".
---
 drivers/net/ixgbe/ixgbe_ethdev.c | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c b/drivers/net/ixgbe/ixgbe_ethdev.c
index cf5f1fe70..57368c79c 100644
--- a/drivers/net/ixgbe/ixgbe_ethdev.c
+++ b/drivers/net/ixgbe/ixgbe_ethdev.c
@@ -94,6 +94,10 @@
 #define IXGBE_4_BIT_MASK   RTE_LEN2MASK(IXGBE_4_BIT_WIDTH, uint8_t)
 #define IXGBE_8_BIT_WIDTH  CHAR_BIT
 #define IXGBE_8_BIT_MASK   UINT8_MAX
+#define IXGBE_32_BIT_WIDTH (CHAR_BIT * 4)
+#define IXGBE_32_BIT_MASK  RTE_LEN2MASK(IXGBE_32_BIT_WIDTH, uint32_t)
+#define IXGBE_36_BIT_WIDTH (CHAR_BIT * 4 + IXGBE_4_BIT_WIDTH)
+#define IXGBE_36_BIT_MASK  RTE_LEN2MASK(IXGBE_36_BIT_WIDTH, uint64_t)
 
 #define IXGBEVF_PMD_NAME "rte_ixgbevf_pmd" /* PMD name */
 
@@ -388,17 +392,29 @@ static int ixgbe_wait_for_link_up(struct ixgbe_hw *hw);
 #define UPDATE_VF_STAT(reg, last, cur)                          \
 {                                                               \
 	uint32_t latest = IXGBE_READ_REG(hw, reg);              \
-	cur += (latest - last) & UINT_MAX;                      \
+	u64 stat = 0;                                           \
+	if (latest >= last)                                     \
+		stat = latest - last;                           \
+	else                                                    \
+		stat = (u64)((latest +                          \
+			((u64)1 << IXGBE_32_BIT_WIDTH)) - last);\
+	cur += stat & IXGBE_32_BIT_MASK;                        \
 	last = latest;                                          \
 }
 
-#define UPDATE_VF_STAT_36BIT(lsb, msb, last, cur)                \
-{                                                                \
-	u64 new_lsb = IXGBE_READ_REG(hw, lsb);                   \
-	u64 new_msb = IXGBE_READ_REG(hw, msb);                   \
-	u64 latest = ((new_msb << 32) | new_lsb);                \
-	cur += (0x1000000000LL + latest - last) & 0xFFFFFFFFFLL; \
-	last = latest;                                           \
+#define UPDATE_VF_STAT_36BIT(lsb, msb, last, cur)               \
+{                                                               \
+	u64 new_lsb = IXGBE_READ_REG(hw, lsb);                  \
+	u64 new_msb = IXGBE_READ_REG(hw, msb);                  \
+	u64 latest = ((new_msb << 32) | new_lsb);               \
+	u64 stat = 0;                                           \
+	if (latest >= last)                                     \
+		stat = latest - last;                           \
+	else                                                    \
+		stat = (u64)((latest +                          \
+			((u64)1 << IXGBE_36_BIT_WIDTH)) - last);\
+	cur += stat & IXGBE_36_BIT_MASK;                        \
+	last = latest;                                          \
 }
 
 #define IXGBE_SET_HWSTRIP(h, q) do {\
-- 
2.17.1