[PATCH v2 3/3] can-isotp: Add error message if txqueuelen is too small

From: Patrick Menschel <menschel.p@posteo.de>
To: Oliver Hartkopp <socketcan@hartkopp.net>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	linux-can@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 3/3] can-isotp: Add error message if txqueuelen is too small
Date: Tue, 27 Apr 2021 05:21:49 +0000	[thread overview]
Message-ID: <20210427052150.2308-4-menschel.p@posteo.de> (raw)
In-Reply-To: <20210427052150.2308-1-menschel.p@posteo.de>

This patch adds an additional error message in
case that txqueuelen is set too small and
advices the user to increase txqueuelen.

This is likely to happen even with small transfers if
txqueuelen is at default value 10 frames.

Signed-off-by: Patrick Menschel <menschel.p@posteo.de>
---
 net/can/isotp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/can/isotp.c b/net/can/isotp.c
index 2075d8d9e..d08f95bfd 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -797,10 +797,12 @@ static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
 		can_skb_set_owner(skb, sk);
 
 		can_send_ret = can_send(skb, 1);
-		if (can_send_ret)
+		if (can_send_ret) {
 			pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
 				       __func__, ERR_PTR(can_send_ret));
-
+			if (can_send_ret == -ENOBUFS)
+				pr_notice_once("can-isotp: tx queue is full, increasing txqueuelen may prevent this error");
+		}
 		if (so->tx.idx >= so->tx.len) {
 			/* we are done */
 			so->tx.state = ISOTP_IDLE;
-- 
2.17.1

