From: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
To: Marc Kleine-Budde <mkl@pengutronix.de>, linux-can@vger.kernel.org
Cc: Oliver Hartkopp <socketcan@hartkopp.net>,
Jimmy Assarsson <extja@kvaser.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-sunxi@lists.linux.dev,
Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Subject: [PATCH v5 2/5] can: kvaser_usb: do not increase tx statistics when sending error message frames
Date: Tue, 7 Dec 2021 21:15:28 +0900 [thread overview]
Message-ID: <20211207121531.42941-3-mailhol.vincent@wanadoo.fr> (raw)
In-Reply-To: <20211207121531.42941-1-mailhol.vincent@wanadoo.fr>
The CAN error message frames (i.e. error skb) are an interface
specific to socket CAN. The payload of the CAN error message frames
does not correspond to any actual data sent on the wire. Only an error
flag and a delimiter are transmitted when an error occurs (c.f. ISO
11898-1 section 10.4.4.2 "Error flag").
For this reason, it makes no sense to increment the tx_packets and
tx_bytes fields of struct net_device_stats when sending an error
message frame because no actual payload will be transmitted on the
wire.
N.B. Sending error message frames is a very specific feature which, at
the moment, is only supported by the Kvaser Hydra hardware. Please
refer to [1] for more details on the topic.
[1] https://lore.kernel.org/linux-can/CAMZ6RqK0rTNg3u3mBpZOoY51jLZ-et-J01tY6-+mWsM4meVw-A@mail.gmail.com/t/#u
Co-developed-by: Jimmy Assarsson <extja@kvaser.com>
Signed-off-by: Jimmy Assarsson <extja@kvaser.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
index 3398da323126..75009d38f8e3 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
@@ -295,6 +295,7 @@ struct kvaser_cmd {
#define KVASER_USB_HYDRA_CF_FLAG_OVERRUN BIT(1)
#define KVASER_USB_HYDRA_CF_FLAG_REMOTE_FRAME BIT(4)
#define KVASER_USB_HYDRA_CF_FLAG_EXTENDED_ID BIT(5)
+#define KVASER_USB_HYDRA_CF_FLAG_TX_ACK BIT(6)
/* CAN frame flags. Used in ext_rx_can and ext_tx_can */
#define KVASER_USB_HYDRA_CF_FLAG_OSM_NACK BIT(12)
#define KVASER_USB_HYDRA_CF_FLAG_ABL BIT(13)
@@ -1113,6 +1114,7 @@ static void kvaser_usb_hydra_tx_acknowledge(const struct kvaser_usb *dev,
struct kvaser_usb_net_priv *priv;
unsigned long irq_flags;
bool one_shot_fail = false;
+ bool is_err_frame = false;
u16 transid = kvaser_usb_hydra_get_cmd_transid(cmd);
priv = kvaser_usb_hydra_net_priv_from_cmd(dev, cmd);
@@ -1131,10 +1133,13 @@ static void kvaser_usb_hydra_tx_acknowledge(const struct kvaser_usb *dev,
kvaser_usb_hydra_one_shot_fail(priv, cmd_ext);
one_shot_fail = true;
}
+
+ is_err_frame = flags & KVASER_USB_HYDRA_CF_FLAG_TX_ACK &&
+ flags & KVASER_USB_HYDRA_CF_FLAG_ERROR_FRAME;
}
context = &priv->tx_contexts[transid % dev->max_tx_urbs];
- if (!one_shot_fail) {
+ if (!one_shot_fail && !is_err_frame) {
struct net_device_stats *stats = &priv->netdev->stats;
stats->tx_packets++;
--
2.32.0
next prev parent reply other threads:[~2021-12-07 12:16 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-07 12:15 [PATCH v5 0/5] fix statistics and payload issues for error Vincent Mailhol
2021-12-07 12:15 ` [PATCH v5 1/5] can: do not increase rx statistics when generating a CAN rx error message frame Vincent Mailhol
2021-12-07 12:15 ` Vincent Mailhol [this message]
2021-12-07 12:15 ` [PATCH v5 3/5] can: do not copy the payload of RTR frames Vincent Mailhol
2021-12-10 7:35 ` Marc Kleine-Budde
2021-12-10 8:02 ` Marc Kleine-Budde
2021-12-10 8:57 ` Yasushi SHOJI
2021-12-07 12:15 ` [PATCH v5 4/5] can: do not increase rx_bytes statistics for " Vincent Mailhol
2021-12-07 12:15 ` [PATCH v5 5/5] can: do not increase tx_bytes " Vincent Mailhol
2021-12-08 9:16 ` [PATCH v5 0/5] fix statistics and payload issues for error Marc Kleine-Budde
2021-12-09 23:21 ` Stefan Mätje
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