[dpdk-stable] [PATCH v2 2/2] net/e1000: fix defects of macro in VF

[Ye Xiaolong]

Hi, guinan

On 05/08, Guinan Sun wrote:
>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.

There was similar patch before, https://patches.dpdk.org/patch/65131/, if I
understand it correctly, you are trying to solve the rollover issue, right?
Could you find the Ferruh's comment and check if this is a real issue?

>
>Fixes: d15fcf76c8b7 ("e1000: move to drivers/net/")

This fix commit isn't correct.

Thanks,
Xiaolong

>Cc: stable at dpdk.org



>
>Signed-off-by: Guinan Sun <guinanx.sun at intel.com>
>---
>v2 changes:
>* Aligned line-continuation character "\".
>---
> drivers/net/e1000/igb_ethdev.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
>diff --git a/drivers/net/e1000/igb_ethdev.c b/drivers/net/e1000/igb_ethdev.c
>index 520fba8fa..4cd4e55c0 100644
>--- a/drivers/net/e1000/igb_ethdev.c
>+++ b/drivers/net/e1000/igb_ethdev.c
>@@ -47,6 +47,8 @@
> #define IGB_4_BIT_MASK   RTE_LEN2MASK(IGB_4_BIT_WIDTH, uint8_t)
> #define IGB_8_BIT_WIDTH  CHAR_BIT
> #define IGB_8_BIT_MASK   UINT8_MAX
>+#define IGB_32_BIT_WIDTH (CHAR_BIT * 4)
>+#define IGB_32_BIT_MASK  RTE_LEN2MASK(IGB_32_BIT_WIDTH, uint32_t)
> 
> /* Additional timesync values. */
> #define E1000_CYCLECOUNTER_MASK      0xffffffffffffffffULL
>@@ -261,11 +263,17 @@ static int igb_filter_restore(struct rte_eth_dev *dev);
> /*
>  * Define VF Stats MACRO for Non "cleared on read" register
>  */
>-#define UPDATE_VF_STAT(reg, last, cur)            \
>-{                                                 \
>-	u32 latest = E1000_READ_REG(hw, reg);     \
>-	cur += (latest - last) & UINT_MAX;        \
>-	last = latest;                            \
>+#define UPDATE_VF_STAT(reg, last, cur)                             \
>+{                                                                  \
>+	uint64_t latest = E1000_READ_REG(hw, reg);                 \
>+	uint64_t stat = 0;                                         \
>+	if (latest >= last)                                        \
>+		stat = latest - last;                              \
>+	else                                                       \
>+		stat = (uint64_t)((latest +                        \
>+			((uint64_t)1 << IGB_32_BIT_WIDTH)) - last);\
>+	cur += stat & IGB_32_BIT_MASK;                             \
>+	last = latest;                                             \
> }
> 
> #define IGB_FC_PAUSE_TIME 0x0680
>-- 
>2.17.1
>