[dpdk-stable] [PATCH 20.11 3/4] net/hns3: fix timing in mailbox

[Xueming(Steven) Li]

Thanks, merged

> -----Original Message-----
> From: Min Hu (Connor) <humin29 at huawei.com>
> Sent: Monday, May 17, 2021 9:51 PM
> To: stable at dpdk.org
> Cc: ferruh.yigit at intel.com; Xueming(Steven) Li <xuemingl at nvidia.com>
> Subject: [PATCH 20.11 3/4] net/hns3: fix timing in mailbox
> 
> From: Chengchang Tang <tangchengchang at huawei.com>
> 
> [ upstream commit d566bfcff0c7bfe167f6c520d4fd5b0104130af6 ]
> 
> Currently, when processing MBX messages, the system timestamp is obtained to determine whether timeout occurs. However, the
> gettimeofday function is not monotonically increasing. Therefore, this may lead to incorrect judgment or difficulty exiting the loop.
> And actually, in this scenario, it is not necessary to obtain the timestamp.
> 
> This patch deletes the call to the gettimeofday function during MBX message processing.
> 
> Fixes: 463e748964f5 ("net/hns3: support mailbox")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Chengchang Tang <tangchengchang at huawei.com>
> Signed-off-by: Min Hu (Connor) <humin29 at huawei.com>
> ---
>  drivers/net/hns3/hns3_mbx.c | 13 +++++--------
>  1 file changed, 5 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/hns3/hns3_mbx.c b/drivers/net/hns3/hns3_mbx.c index 11e5235..2a479f2 100644
> --- a/drivers/net/hns3/hns3_mbx.c
> +++ b/drivers/net/hns3/hns3_mbx.c
> @@ -61,13 +61,12 @@ static int
>  hns3_get_mbx_resp(struct hns3_hw *hw, uint16_t code, uint16_t subcode,
>  		  uint8_t *resp_data, uint16_t resp_len)  {
> -#define HNS3_MAX_RETRY_MS	500
> +#define HNS3_MAX_RETRY_US	500000
>  #define HNS3_WAIT_RESP_US	100
>  	struct hns3_adapter *hns = HNS3_DEV_HW_TO_ADAPTER(hw);
>  	struct hns3_mbx_resp_status *mbx_resp;
> +	uint32_t wait_time = 0;
>  	bool received;
> -	uint64_t now;
> -	uint64_t end;
> 
>  	if (resp_len > HNS3_MBX_MAX_RESP_DATA_SIZE) {
>  		hns3_err(hw, "VF mbx response len(=%u) exceeds maximum(=%d)", @@ -75,9 +74,7 @@ hns3_get_mbx_resp(struct
> hns3_hw *hw, uint16_t code, uint16_t subcode,
>  		return -EINVAL;
>  	}
> 
> -	now = get_timeofday_ms();
> -	end = now + HNS3_MAX_RETRY_MS;
> -	while (now < end) {
> +	while (wait_time < HNS3_MAX_RETRY_US) {
>  		if (rte_atomic16_read(&hw->reset.disable_cmd)) {
>  			hns3_err(hw, "Don't wait for mbx respone because of "
>  				 "disable_cmd");
> @@ -103,10 +100,10 @@ hns3_get_mbx_resp(struct hns3_hw *hw, uint16_t code, uint16_t subcode,
>  		if (received)
>  			break;
> 
> -		now = get_timeofday_ms();
> +		wait_time += HNS3_WAIT_RESP_US;
>  	}
>  	hw->mbx_resp.req_msg_data = 0;
> -	if (now >= end) {
> +	if (wait_time >= HNS3_MAX_RETRY_US) {
>  		hns3_mbx_proc_timeout(hw, code, subcode);
>  		return -ETIME;
>  	}
> --
> 2.7.4