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From:   Vincent Mailhol <mailhol.vincent@wanadoo.fr>
To:     linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        linux-can@vger.kernel.org, Wolfgang Grandegger <wg@grandegger.com>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        "David S . Miller" <davem@davemloft.net>
Cc:     Vincent Mailhol <mailhol.vincent@wanadoo.fr>,
        Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 3/6] can: dev: __can_get_echo_skb(): fix the return length
Date:   Sun, 27 Sep 2020 02:57:53 +0900
Message-Id: <20200926175810.278529-4-mailhol.vincent@wanadoo.fr>
In-Reply-To: <20200926175810.278529-1-mailhol.vincent@wanadoo.fr>
References: <20200926175810.278529-1-mailhol.vincent@wanadoo.fr>
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The length of Remote Transmission Request (RTR) frames is always 0
bytes. The DLC represents the requested length, not the actual length
of the RTR. But __can_get_echo_skb() returns the DLC value regardless.

Apply get_can_len() function to retrieve the correct length.

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
 drivers/net/can/dev.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index e291fda395a0..8c3e11820e03 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -481,14 +481,9 @@ __can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
 	}
 
 	if (priv->echo_skb[idx]) {
-		/* Using "struct canfd_frame::len" for the frame
-		 * length is supported on both CAN and CANFD frames.
-		 */
 		struct sk_buff *skb = priv->echo_skb[idx];
-		struct canfd_frame *cf = (struct canfd_frame *)skb->data;
-		u8 len = cf->len;
 
-		*len_ptr = len;
+		*len_ptr = get_can_len(skb);
 		priv->echo_skb[idx] = NULL;
 
 		return skb;
-- 
2.26.2