[PATCH net v2] ravb: Fix bit fields checking in ravb_hwtstamp_get()

[PATCH net v2] ravb: Fix bit fields checking in ravb_hwtstamp_get()

[Andrew Gabbasov]

In the function ravb_hwtstamp_get() in ravb_main.c with the existing
values for RAVB_RXTSTAMP_TYPE_V2_L2_EVENT (0x2) and RAVB_RXTSTAMP_TYPE_ALL
(0x6)

if (priv->tstamp_rx_ctrl & RAVB_RXTSTAMP_TYPE_V2_L2_EVENT)
	config.rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
else if (priv->tstamp_rx_ctrl & RAVB_RXTSTAMP_TYPE_ALL)
	config.rx_filter = HWTSTAMP_FILTER_ALL;

if the test on RAVB_RXTSTAMP_TYPE_ALL should be true,
it will never be reached.

This issue can be verified with 'hwtstamp_config' testing program
(tools/testing/selftests/net/hwtstamp_config.c). Setting filter type
to ALL and subsequent retrieving it gives incorrect value:

$ hwtstamp_config eth0 OFF ALL
flags = 0
tx_type = OFF
rx_filter = ALL
$ hwtstamp_config eth0
flags = 0
tx_type = OFF
rx_filter = PTP_V2_L2_EVENT

Correct this by converting if-else's to switch.

Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
Reported-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@gmail.com>
---
 drivers/net/ethernet/renesas/ravb_main.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 9c4df4ede011..bd30505fbc57 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1744,12 +1744,16 @@ static int ravb_hwtstamp_get(struct net_device *ndev, struct ifreq *req)
 	config.flags = 0;
 	config.tx_type = priv->tstamp_tx_ctrl ? HWTSTAMP_TX_ON :
 						HWTSTAMP_TX_OFF;
-	if (priv->tstamp_rx_ctrl & RAVB_RXTSTAMP_TYPE_V2_L2_EVENT)
+	switch (priv->tstamp_rx_ctrl & RAVB_RXTSTAMP_TYPE) {
+	case RAVB_RXTSTAMP_TYPE_V2_L2_EVENT:
 		config.rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
-	else if (priv->tstamp_rx_ctrl & RAVB_RXTSTAMP_TYPE_ALL)
+		break;
+	case RAVB_RXTSTAMP_TYPE_ALL:
 		config.rx_filter = HWTSTAMP_FILTER_ALL;
-	else
+		break;
+	default:
 		config.rx_filter = HWTSTAMP_FILTER_NONE;
+	}
 
 	return copy_to_user(req->ifr_data, &config, sizeof(config)) ?
 		-EFAULT : 0;
-- 
2.21.0

Re: [PATCH net v2] ravb: Fix bit fields checking in ravb_hwtstamp_get()

[Jakub Kicinski]

On Mon, 26 Oct 2020 05:21:30 -0500 Andrew Gabbasov wrote:
> In the function ravb_hwtstamp_get() in ravb_main.c with the existing
> values for RAVB_RXTSTAMP_TYPE_V2_L2_EVENT (0x2) and RAVB_RXTSTAMP_TYPE_ALL
> (0x6)
> 
> if (priv->tstamp_rx_ctrl & RAVB_RXTSTAMP_TYPE_V2_L2_EVENT)
> 	config.rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
> else if (priv->tstamp_rx_ctrl & RAVB_RXTSTAMP_TYPE_ALL)
> 	config.rx_filter = HWTSTAMP_FILTER_ALL;
> 
> if the test on RAVB_RXTSTAMP_TYPE_ALL should be true,
> it will never be reached.
> 
> This issue can be verified with 'hwtstamp_config' testing program
> (tools/testing/selftests/net/hwtstamp_config.c). Setting filter type
> to ALL and subsequent retrieving it gives incorrect value:
> 
> $ hwtstamp_config eth0 OFF ALL
> flags = 0
> tx_type = OFF
> rx_filter = ALL
> $ hwtstamp_config eth0
> flags = 0
> tx_type = OFF
> rx_filter = PTP_V2_L2_EVENT
> 
> Correct this by converting if-else's to switch.
> 
> Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
> Reported-by: Julia Lawall <julia.lawall@inria.fr>
> Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
> Reviewed-by: Sergei Shtylyov <sergei.shtylyov@gmail.com>

Applied, thank you!