can: do not increase tx_bytes statistics for RTR frames

The actual payload length of the CAN Remote Transmission Request (RTR)
frames is always 0, i.e. no payload is transmitted on the wire.
However, those RTR frames still use the DLC to indicate the length of
the requested frame.

As such, net_device_stats::tx_bytes should not be increased when
sending RTR frames.

The function can_get_echo_skb() already returns the correct length,
even for RTR frames (c.f. [1]). However, for historical reasons, the
drivers do not use can_get_echo_skb()'s return value and instead, most
of them store a temporary length (or dlc) in some local structure or
array. Using the return value of can_get_echo_skb() solves the
issue. After doing this, such length/dlc fields become unused and so
this patch does the adequate cleaning when needed.

This patch fixes all the CAN drivers.

Finally, can_get_echo_skb() is decorated with the __must_check
attribute in order to force future drivers to correctly use its return
value (else the compiler would emit a warning).

[1] commit ed3320ce ("can: dev: __can_get_echo_skb():
fix real payload length return value for RTR frames")

Link: https://lore.kernel.org/all/20211207121531.42941-6-mailhol.vincent@wanadoo.fr
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Jernej Skrabec <jernej.skrabec@gmail.com>
Cc: Yasushi SHOJI <yashi@spacecubics.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Stephane Grosjean <s.grosjean@peak-system.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Tested-by: Jimmy Assarsson <extja@kvaser.com> # kvaser
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Acked-by: Stefan Mätje <stefan.maetje@esd.eu> # esd_usb2
Tested-by: Stefan Mätje <stefan.maetje@esd.eu> # esd_usb2
[mkl: add conversion for grcan]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/at91_can.c

@@ -448,7 +448,6 @@ static void at91_chip_stop(struct net_device *dev, enum can_state state)
 static netdev_tx_t at91_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct at91_priv *priv = netdev_priv(dev);
-	struct net_device_stats *stats = &dev->stats;
 	struct can_frame *cf = (struct can_frame *)skb->data;
 	unsigned int mb, prio;
 	u32 reg_mid, reg_mcr;
@@ -480,8 +479,6 @@ static netdev_tx_t at91_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* This triggers transmission */
 	at91_write(priv, AT91_MCR(mb), reg_mcr);
 
-	stats->tx_bytes += cf->len;
-
 	/* _NOTE_: subtract AT91_MB_TX_FIRST offset from mb! */
 	can_put_echo_skb(skb, dev, mb - get_mb_tx_first(priv), 0);
 
@@ -852,7 +849,10 @@ static void at91_irq_tx(struct net_device *dev, u32 reg_sr)
 		if (likely(reg_msr & AT91_MSR_MRDY &&
 			   ~reg_msr & AT91_MSR_MABT)) {
 			/* _NOTE_: subtract AT91_MB_TX_FIRST offset from mb! */
-			can_get_echo_skb(dev, mb - get_mb_tx_first(priv), NULL);
+			dev->stats.tx_bytes +=
+				can_get_echo_skb(dev,
+						 mb - get_mb_tx_first(priv),
+						 NULL);
 			dev->stats.tx_packets++;
 			can_led_event(dev, CAN_LED_EVENT_TX);
 		}

drivers/net/can/c_can/c_can.h

@@ -211,7 +211,6 @@ struct c_can_priv {
 	struct c_can_raminit raminit_sys;	/* RAMINIT via syscon regmap */
 	void (*raminit)(const struct c_can_priv *priv, bool enable);
 	u32 comm_rcv_high;
-	u32 dlc[];
 };
 
 struct net_device *alloc_c_can_dev(int msg_obj_num);

drivers/net/can/c_can/c_can_main.c

@@ -477,7 +477,6 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
 	 * transmit as we might race against do_tx().
 	 */
 	c_can_setup_tx_object(dev, IF_TX, frame, idx);
-	priv->dlc[idx] = frame->len;
 	can_put_echo_skb(skb, dev, idx, 0);
 	obj = idx + priv->msg_obj_tx_first;
 	c_can_object_put(dev, IF_TX, obj, cmd);
@@ -742,8 +741,7 @@ static void c_can_do_tx(struct net_device *dev)
 		 * NAPI. We are not transmitting.
 		 */
 		c_can_inval_tx_object(dev, IF_NAPI, obj);
-		can_get_echo_skb(dev, idx, NULL);
-		bytes += priv->dlc[idx];
+		bytes += can_get_echo_skb(dev, idx, NULL);
 		pkts++;
 	}
 
@@ -1227,8 +1225,7 @@ struct net_device *alloc_c_can_dev(int msg_obj_num)
 	struct c_can_priv *priv;
 	int msg_obj_tx_num = msg_obj_num / 2;
 
-	dev = alloc_candev(struct_size(priv, dlc, msg_obj_tx_num),
-			   msg_obj_tx_num);
+	dev = alloc_candev(sizeof(*priv), msg_obj_tx_num);
 	if (!dev)
 		return NULL;
 

drivers/net/can/cc770/cc770.c

@@ -664,7 +664,6 @@ static void cc770_tx_interrupt(struct net_device *dev, unsigned int o)
 	struct cc770_priv *priv = netdev_priv(dev);
 	struct net_device_stats *stats = &dev->stats;
 	unsigned int mo = obj2msgobj(o);
-	struct can_frame *cf;
 	u8 ctrl1;
 
 	ctrl1 = cc770_read_reg(priv, msgobj[mo].ctrl1);
@@ -696,12 +695,9 @@ static void cc770_tx_interrupt(struct net_device *dev, unsigned int o)
 		return;
 	}
 
-	cf = (struct can_frame *)priv->tx_skb->data;
-	stats->tx_bytes += cf->len;
-	stats->tx_packets++;
-
 	can_put_echo_skb(priv->tx_skb, dev, 0, 0);
-	can_get_echo_skb(dev, 0, NULL);
+	stats->tx_bytes += can_get_echo_skb(dev, 0, NULL);
+	stats->tx_packets++;
 	priv->tx_skb = NULL;
 
 	netif_wake_queue(dev);

drivers/net/can/grcan.c

@@ -255,7 +255,6 @@ struct grcan_priv {
 	struct grcan_dma dma;
 
 	struct sk_buff **echo_skb;	/* We allocate this on our own */
-	u8 *txdlc;			/* Length of queued frames */
 
 	/* The echo skb pointer, pointing into echo_skb and indicating which
 	 * frames can be echoed back. See the "Notes on the tx cyclic buffer
@@ -515,9 +514,7 @@ static int catch_up_echo_skb(struct net_device *dev, int budget, bool echo)
 		if (echo) {
 			/* Normal echo of messages */
 			stats->tx_packets++;
-			stats->tx_bytes += priv->txdlc[i];
-			priv->txdlc[i] = 0;
-			can_get_echo_skb(dev, i, NULL);
+			stats->tx_bytes += can_get_echo_skb(dev, i, NULL);
 		} else {
 			/* For cleanup of untransmitted messages */
 			can_free_echo_skb(dev, i, NULL);
@@ -1062,16 +1059,10 @@ static int grcan_open(struct net_device *dev)
 	priv->can.echo_skb_max = dma->tx.size;
 	priv->can.echo_skb = priv->echo_skb;
 
-	priv->txdlc = kcalloc(dma->tx.size, sizeof(*priv->txdlc), GFP_KERNEL);
-	if (!priv->txdlc) {
-		err = -ENOMEM;
-		goto exit_free_echo_skb;
-	}
-
 	/* Get can device up */
 	err = open_candev(dev);
 	if (err)
-		goto exit_free_txdlc;
+		goto exit_free_echo_skb;
 
 	err = request_irq(dev->irq, grcan_interrupt, IRQF_SHARED,
 			  dev->name, dev);
@@ -1093,8 +1084,6 @@ static int grcan_open(struct net_device *dev)
 
 exit_close_candev:
 	close_candev(dev);
-exit_free_txdlc:
-	kfree(priv->txdlc);
 exit_free_echo_skb:
 	kfree(priv->echo_skb);
 exit_free_dma_buffers:
@@ -1129,7 +1118,6 @@ static int grcan_close(struct net_device *dev)
 	priv->can.echo_skb_max = 0;
 	priv->can.echo_skb = NULL;
 	kfree(priv->echo_skb);
-	kfree(priv->txdlc);
 
 	return 0;
 }
@@ -1447,7 +1435,6 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff *skb,
 	 * can_put_echo_skb would be an error unless other measures are
 	 * taken.
 	 */
-	priv->txdlc[slotindex] = cf->len; /* Store dlc for statistics */
 	can_put_echo_skb(skb, dev, slotindex, 0);
 
 	/* Make sure everything is written before allowing hardware to

drivers/net/can/janz-ican3.c

@@ -1294,7 +1294,8 @@ static unsigned int ican3_get_echo_skb(struct ican3_dev *mod)
 	}
 
 	cf = (struct can_frame *)skb->data;
-	dlc = cf->len;
+	if (!(cf->can_id & CAN_RTR_FLAG))
+		dlc = cf->len;
 
 	/* check flag whether this packet has to be looped back */
 	if (skb->pkt_type != PACKET_LOOPBACK) {

drivers/net/can/mscan/mscan.c

@@ -448,9 +448,9 @@ static irqreturn_t mscan_isr(int irq, void *dev_id)
 				continue;
 
 			out_8(&regs->cantbsel, mask);
-			stats->tx_bytes += in_8(&regs->tx.dlr);
+			stats->tx_bytes += can_get_echo_skb(dev, entry->id,
+							    NULL);
 			stats->tx_packets++;
-			can_get_echo_skb(dev, entry->id, NULL);
 			priv->tx_active &= ~mask;
 			list_del(pos);
 		}

drivers/net/can/pch_can.c

@@ -707,16 +707,13 @@ static void pch_can_tx_complete(struct net_device *ndev, u32 int_stat)
 {
 	struct pch_can_priv *priv = netdev_priv(ndev);
 	struct net_device_stats *stats = &(priv->ndev->stats);
-	u32 dlc;
 
-	can_get_echo_skb(ndev, int_stat - PCH_RX_OBJ_END - 1, NULL);
+	stats->tx_bytes += can_get_echo_skb(ndev, int_stat - PCH_RX_OBJ_END - 1,
+					    NULL);
+	stats->tx_packets++;
 	iowrite32(PCH_CMASK_RX_TX_GET | PCH_CMASK_CLRINTPND,
 		  &priv->regs->ifregs[1].cmask);
 	pch_can_rw_msg_obj(&priv->regs->ifregs[1].creq, int_stat);
-	dlc = can_cc_dlc2len(ioread32(&priv->regs->ifregs[1].mcont) &
-			  PCH_IF_MCONT_DLC);
-	stats->tx_bytes += dlc;
-	stats->tx_packets++;
 	if (int_stat == PCH_TX_OBJ_END)
 		netif_wake_queue(ndev);
 }

drivers/net/can/peak_canfd/peak_canfd.c

@@ -266,10 +266,9 @@ static int pucan_handle_can_rx(struct peak_canfd_priv *priv,
 		unsigned long flags;
 
 		spin_lock_irqsave(&priv->echo_lock, flags);
-		can_get_echo_skb(priv->ndev, msg->client, NULL);
 
 		/* count bytes of the echo instead of skb */
-		stats->tx_bytes += cf_len;
+		stats->tx_bytes += can_get_echo_skb(priv->ndev, msg->client, NULL);
 		stats->tx_packets++;
 
 		/* restart tx queue (a slot is free) */

drivers/net/can/rcar/rcar_can.c

@@ -94,7 +94,6 @@ struct rcar_can_priv {
 	struct rcar_can_regs __iomem *regs;
 	struct clk *clk;
 	struct clk *can_clk;
-	u8 tx_dlc[RCAR_CAN_FIFO_DEPTH];
 	u32 tx_head;
 	u32 tx_tail;
 	u8 clock_select;
@@ -379,10 +378,11 @@ static void rcar_can_tx_done(struct net_device *ndev)
 		if (priv->tx_head - priv->tx_tail <= unsent)
 			break;
 		stats->tx_packets++;
-		stats->tx_bytes += priv->tx_dlc[priv->tx_tail %
-						RCAR_CAN_FIFO_DEPTH];
-		priv->tx_dlc[priv->tx_tail % RCAR_CAN_FIFO_DEPTH] = 0;
-		can_get_echo_skb(ndev, priv->tx_tail % RCAR_CAN_FIFO_DEPTH, NULL);
+		stats->tx_bytes +=
+			can_get_echo_skb(ndev,
+					 priv->tx_tail % RCAR_CAN_FIFO_DEPTH,
+					 NULL);
+
 		priv->tx_tail++;
 		netif_wake_queue(ndev);
 	}
@@ -612,7 +612,6 @@ static netdev_tx_t rcar_can_start_xmit(struct sk_buff *skb,
 
 	writeb(cf->len, &priv->regs->mb[RCAR_CAN_TX_FIFO_MBX].dlc);
 
-	priv->tx_dlc[priv->tx_head % RCAR_CAN_FIFO_DEPTH] = cf->len;
 	can_put_echo_skb(skb, ndev, priv->tx_head % RCAR_CAN_FIFO_DEPTH, 0);
 	priv->tx_head++;
 	/* Start Tx: write 0xff to the TFPCR register to increment

drivers/net/can/rcar/rcar_canfd.c

@@ -502,7 +502,6 @@ struct rcar_canfd_channel {
 	struct rcar_canfd_global *gpriv;	/* Controller reference */
 	void __iomem *base;			/* Register base address */
 	struct napi_struct napi;
-	u8  tx_len[RCANFD_FIFO_DEPTH];		/* For net stats */
 	u32 tx_head;				/* Incremented on xmit */
 	u32 tx_tail;				/* Incremented on xmit done */
 	u32 channel;				/* Channel number */
@@ -1049,9 +1048,7 @@ static void rcar_canfd_tx_done(struct net_device *ndev)
 
 		sent = priv->tx_tail % RCANFD_FIFO_DEPTH;
 		stats->tx_packets++;
-		stats->tx_bytes += priv->tx_len[sent];
-		priv->tx_len[sent] = 0;
-		can_get_echo_skb(ndev, sent, NULL);
+		stats->tx_bytes += can_get_echo_skb(ndev, sent, NULL);
 
 		spin_lock_irqsave(&priv->tx_lock, flags);
 		priv->tx_tail++;
@@ -1461,7 +1458,6 @@ static netdev_tx_t rcar_canfd_start_xmit(struct sk_buff *skb,
 				    RCANFD_C_CFDF(ch, RCANFD_CFFIFO_IDX, 0));
 	}
 
-	priv->tx_len[priv->tx_head % RCANFD_FIFO_DEPTH] = cf->len;
 	can_put_echo_skb(skb, ndev, priv->tx_head % RCANFD_FIFO_DEPTH, 0);
 
 	spin_lock_irqsave(&priv->tx_lock, flags);

drivers/net/can/sja1000/sja1000.c

@@ -527,10 +527,8 @@ irqreturn_t sja1000_interrupt(int irq, void *dev_id)
 				can_free_echo_skb(dev, 0, NULL);
 			} else {
 				/* transmission complete */
-				stats->tx_bytes +=
-					priv->read_reg(priv, SJA1000_FI) & 0xf;
+				stats->tx_bytes += can_get_echo_skb(dev, 0, NULL);
 				stats->tx_packets++;
-				can_get_echo_skb(dev, 0, NULL);
 			}
 			netif_wake_queue(dev);
 			can_led_event(dev, CAN_LED_EVENT_TX);

drivers/net/can/slcan.c

@@ -290,6 +290,8 @@ static void slc_encaps(struct slcan *sl, struct can_frame *cf)
 	if (!(cf->can_id & CAN_RTR_FLAG)) {
 		for (i = 0; i < cf->len; i++)
 			pos = hex_byte_pack_upper(pos, cf->data[i]);
+
+		sl->dev->stats.tx_bytes += cf->len;
 	}
 
 	*pos++ = '\r';
@@ -306,7 +308,6 @@ static void slc_encaps(struct slcan *sl, struct can_frame *cf)
 	actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff);
 	sl->xleft = (pos - sl->xbuff) - actual;
 	sl->xhead = sl->xbuff + actual;
-	sl->dev->stats.tx_bytes += cf->len;
 }
 
 /* Write out any remaining transmit buffer. Scheduled when tty is writable */

drivers/net/can/softing/softing_main.c

@@ -282,7 +282,10 @@ static int softing_handle_1(struct softing *card)
 			skb = priv->can.echo_skb[priv->tx.echo_get];
 			if (skb)
 				skb->tstamp = ktime;
-			can_get_echo_skb(netdev, priv->tx.echo_get, NULL);
+			++netdev->stats.tx_packets;
+			netdev->stats.tx_bytes +=
+				can_get_echo_skb(netdev, priv->tx.echo_get,
+						 NULL);
 			++priv->tx.echo_get;
 			if (priv->tx.echo_get >= TX_ECHO_SKB_MAX)
 				priv->tx.echo_get = 0;
@@ -290,9 +293,6 @@ static int softing_handle_1(struct softing *card)
 				--priv->tx.pending;
 			if (card->tx.pending)
 				--card->tx.pending;
-			++netdev->stats.tx_packets;
-			if (!(msg.can_id & CAN_RTR_FLAG))
-				netdev->stats.tx_bytes += msg.len;
 		} else {
 			int ret;
 

drivers/net/can/spi/hi311x.c

@@ -153,7 +153,6 @@ struct hi3110_priv {
 	u8 *spi_rx_buf;
 
 	struct sk_buff *tx_skb;
-	int tx_len;
 
 	struct workqueue_struct *wq;
 	struct work_struct tx_work;
@@ -166,6 +165,8 @@ struct hi3110_priv {
 #define HI3110_AFTER_SUSPEND_POWER 4
 #define HI3110_AFTER_SUSPEND_RESTART 8
 	int restart_tx;
+	bool tx_busy;
+
 	struct regulator *power;
 	struct regulator *transceiver;
 	struct clk *clk;
@@ -175,13 +176,13 @@ static void hi3110_clean(struct net_device *net)
 {
 	struct hi3110_priv *priv = netdev_priv(net);
 
-	if (priv->tx_skb || priv->tx_len)
+	if (priv->tx_skb || priv->tx_busy)
 		net->stats.tx_errors++;
 	dev_kfree_skb(priv->tx_skb);
-	if (priv->tx_len)
+	if (priv->tx_busy)
 		can_free_echo_skb(priv->net, 0, NULL);
 	priv->tx_skb = NULL;
-	priv->tx_len = 0;
+	priv->tx_busy = false;
 }
 
 /* Note about handling of error return of hi3110_spi_trans: accessing
@@ -369,7 +370,7 @@ static netdev_tx_t hi3110_hard_start_xmit(struct sk_buff *skb,
 	struct hi3110_priv *priv = netdev_priv(net);
 	struct spi_device *spi = priv->spi;
 
-	if (priv->tx_skb || priv->tx_len) {
+	if (priv->tx_skb || priv->tx_busy) {
 		dev_err(&spi->dev, "hard_xmit called while tx busy\n");
 		return NETDEV_TX_BUSY;
 	}
@@ -586,7 +587,7 @@ static void hi3110_tx_work_handler(struct work_struct *ws)
 		} else {
 			frame = (struct can_frame *)priv->tx_skb->data;
 			hi3110_hw_tx(spi, frame);
-			priv->tx_len = 1 + frame->len;
+			priv->tx_busy = true;
 			can_put_echo_skb(priv->tx_skb, net, 0, 0);
 			priv->tx_skb = NULL;
 		}
@@ -721,14 +722,11 @@ static irqreturn_t hi3110_can_ist(int irq, void *dev_id)
 			}
 		}
 
-		if (priv->tx_len && statf & HI3110_STAT_TXMTY) {
+		if (priv->tx_busy && statf & HI3110_STAT_TXMTY) {
 			net->stats.tx_packets++;
-			net->stats.tx_bytes += priv->tx_len - 1;
+			net->stats.tx_bytes += can_get_echo_skb(net, 0, NULL);
 			can_led_event(net, CAN_LED_EVENT_TX);
-			if (priv->tx_len) {
-				can_get_echo_skb(net, 0, NULL);
-				priv->tx_len = 0;
-			}
+			priv->tx_busy = false;
 			netif_wake_queue(net);
 		}
 
@@ -755,7 +753,7 @@ static int hi3110_open(struct net_device *net)
 
 	priv->force_quit = 0;
 	priv->tx_skb = NULL;
-	priv->tx_len = 0;
+	priv->tx_busy = false;
 
 	ret = request_threaded_irq(spi->irq, NULL, hi3110_can_ist,
 				   flags, DEVICE_NAME, priv);

drivers/net/can/spi/mcp251x.c

@@ -237,7 +237,6 @@ struct mcp251x_priv {
 	u8 *spi_rx_buf;
 
 	struct sk_buff *tx_skb;
-	int tx_len;
 
 	struct workqueue_struct *wq;
 	struct work_struct tx_work;
@@ -250,6 +249,8 @@ struct mcp251x_priv {
 #define AFTER_SUSPEND_POWER 4
 #define AFTER_SUSPEND_RESTART 8
 	int restart_tx;
+	bool tx_busy;
+
 	struct regulator *power;
 	struct regulator *transceiver;
 	struct clk *clk;
@@ -272,13 +273,13 @@ static void mcp251x_clean(struct net_device *net)
 {
 	struct mcp251x_priv *priv = netdev_priv(net);
 
-	if (priv->tx_skb || priv->tx_len)
+	if (priv->tx_skb || priv->tx_busy)
 		net->stats.tx_errors++;
 	dev_kfree_skb(priv->tx_skb);
-	if (priv->tx_len)
+	if (priv->tx_busy)
 		can_free_echo_skb(priv->net, 0, NULL);
 	priv->tx_skb = NULL;
-	priv->tx_len = 0;
+	priv->tx_busy = false;
 }
 
 /* Note about handling of error return of mcp251x_spi_trans: accessing
@@ -785,7 +786,7 @@ static netdev_tx_t mcp251x_hard_start_xmit(struct sk_buff *skb,
 	struct mcp251x_priv *priv = netdev_priv(net);
 	struct spi_device *spi = priv->spi;
 
-	if (priv->tx_skb || priv->tx_len) {
+	if (priv->tx_skb || priv->tx_busy) {
 		dev_warn(&spi->dev, "hard_xmit called while tx busy\n");
 		return NETDEV_TX_BUSY;
 	}
@@ -1010,7 +1011,7 @@ static void mcp251x_tx_work_handler(struct work_struct *ws)
 			if (frame->len > CAN_FRAME_MAX_DATA_LEN)
 				frame->len = CAN_FRAME_MAX_DATA_LEN;
 			mcp251x_hw_tx(spi, frame, 0);
-			priv->tx_len = 1 + frame->len;
+			priv->tx_busy = true;
 			can_put_echo_skb(priv->tx_skb, net, 0, 0);
 			priv->tx_skb = NULL;
 		}
@@ -1176,12 +1177,12 @@ static irqreturn_t mcp251x_can_ist(int irq, void *dev_id)
 			break;
 
 		if (intf & CANINTF_TX) {
-			net->stats.tx_packets++;
-			net->stats.tx_bytes += priv->tx_len - 1;
 			can_led_event(net, CAN_LED_EVENT_TX);
-			if (priv->tx_len) {
-				can_get_echo_skb(net, 0, NULL);
-				priv->tx_len = 0;
+			if (priv->tx_busy) {
+				net->stats.tx_packets++;
+				net->stats.tx_bytes += can_get_echo_skb(net, 0,
+									NULL);
+				priv->tx_busy = false;
 			}
 			netif_wake_queue(net);
 		}
@@ -1208,7 +1209,7 @@ static int mcp251x_open(struct net_device *net)
 
 	priv->force_quit = 0;
 	priv->tx_skb = NULL;
-	priv->tx_len = 0;
+	priv->tx_busy = false;
 
 	if (!dev_fwnode(&spi->dev))
 		flags = IRQF_TRIGGER_FALLING;

drivers/net/can/sun4i_can.c

@@ -661,11 +661,8 @@ static irqreturn_t sun4i_can_interrupt(int irq, void *dev_id)
 
 		if (isrc & SUN4I_INT_TBUF_VLD) {
 			/* transmission complete interrupt */
-			stats->tx_bytes +=
-			    readl(priv->base +
-				  SUN4I_REG_RBUF_RBACK_START_ADDR) & 0xf;
+			stats->tx_bytes += can_get_echo_skb(dev, 0, NULL);
 			stats->tx_packets++;
-			can_get_echo_skb(dev, 0, NULL);
 			netif_wake_queue(dev);
 			can_led_event(dev, CAN_LED_EVENT_TX);
 		}

drivers/net/can/usb/ems_usb.c

@@ -230,7 +230,6 @@ struct ems_tx_urb_context {
 	struct ems_usb *dev;
 
 	u32 echo_index;
-	u8 dlc;
 };
 
 struct ems_usb {
@@ -517,9 +516,8 @@ static void ems_usb_write_bulk_callback(struct urb *urb)
 
 	/* transmission complete interrupt */
 	netdev->stats.tx_packets++;
-	netdev->stats.tx_bytes += context->dlc;
-
-	can_get_echo_skb(netdev, context->echo_index, NULL);
+	netdev->stats.tx_bytes += can_get_echo_skb(netdev, context->echo_index,
+						   NULL);
 
 	/* Release context */
 	context->echo_index = MAX_TX_URBS;
@@ -805,7 +803,6 @@ static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *ne
 
 	context->dev = dev;
 	context->echo_index = i;
-	context->dlc = cf->len;
 
 	usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
 			  size, ems_usb_write_bulk_callback, context);

drivers/net/can/usb/esd_usb2.c

@@ -183,7 +183,6 @@ struct esd_usb2_net_priv;
 struct esd_tx_urb_context {
 	struct esd_usb2_net_priv *priv;
 	u32 echo_index;
-	int len;	/* CAN payload length */
 };
 
 struct esd_usb2 {
@@ -357,8 +356,8 @@ static void esd_usb2_tx_done_msg(struct esd_usb2_net_priv *priv,
 
 	if (!msg->msg.txdone.status) {
 		stats->tx_packets++;
-		stats->tx_bytes += context->len;
-		can_get_echo_skb(netdev, context->echo_index, NULL);
+		stats->tx_bytes += can_get_echo_skb(netdev, context->echo_index,
+						    NULL);
 	} else {
 		stats->tx_errors++;
 		can_free_echo_skb(netdev, context->echo_index, NULL);
@@ -783,7 +782,6 @@ static netdev_tx_t esd_usb2_start_xmit(struct sk_buff *skb,
 
 	context->priv = priv;
 	context->echo_index = i;
-	context->len = cf->len;
 
 	/* hnd must not be 0 - MSB is stripped in txdone handling */
 	msg->msg.tx.hnd = 0x80000000 | i; /* returned in TX done message */

drivers/net/can/usb/gs_usb.c

@@ -357,9 +357,6 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 			goto resubmit_urb;
 		}
 
-		netdev->stats.tx_packets++;
-		netdev->stats.tx_bytes += hf->can_dlc;
-
 		txc = gs_get_tx_context(dev, hf->echo_id);
 
 		/* bad devices send bad echo_ids. */
@@ -370,7 +367,9 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 			goto resubmit_urb;
 		}
 
-		can_get_echo_skb(netdev, hf->echo_id, NULL);
+		netdev->stats.tx_packets++;
+		netdev->stats.tx_bytes += can_get_echo_skb(netdev, hf->echo_id,
+							   NULL);
 
 		gs_free_tx_context(txc);
 

drivers/net/can/usb/kvaser_usb/kvaser_usb.h

@@ -77,7 +77,6 @@ struct kvaser_usb_dev_card_data {
 struct kvaser_usb_tx_urb_context {
 	struct kvaser_usb_net_priv *priv;
 	u32 echo_index;
-	int dlc;
 };
 
 struct kvaser_usb {
@@ -162,8 +161,8 @@ struct kvaser_usb_dev_ops {
 	void (*dev_read_bulk_callback)(struct kvaser_usb *dev, void *buf,
 				       int len);
 	void *(*dev_frame_to_cmd)(const struct kvaser_usb_net_priv *priv,
-				  const struct sk_buff *skb, int *frame_len,
-				  int *cmd_len, u16 transid);
+				  const struct sk_buff *skb, int *cmd_len,
+				  u16 transid);
 };
 
 struct kvaser_usb_dev_cfg {

drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c

@@ -565,7 +565,7 @@ static netdev_tx_t kvaser_usb_start_xmit(struct sk_buff *skb,
 		goto freeurb;
 	}
 
-	buf = dev->ops->dev_frame_to_cmd(priv, skb, &context->dlc, &cmd_len,
+	buf = dev->ops->dev_frame_to_cmd(priv, skb, &cmd_len,
 					 context->echo_index);
 	if (!buf) {
 		stats->tx_dropped++;

drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c

@@ -1114,6 +1114,7 @@ static void kvaser_usb_hydra_tx_acknowledge(const struct kvaser_usb *dev,
 	struct kvaser_usb_tx_urb_context *context;
 	struct kvaser_usb_net_priv *priv;
 	unsigned long irq_flags;
+	unsigned int len;
 	bool one_shot_fail = false;
 	bool is_err_frame = false;
 	u16 transid = kvaser_usb_hydra_get_cmd_transid(cmd);
@@ -1140,21 +1141,22 @@ static void kvaser_usb_hydra_tx_acknowledge(const struct kvaser_usb *dev,
 	}
 
 	context = &priv->tx_contexts[transid % dev->max_tx_urbs];
-	if (!one_shot_fail && !is_err_frame) {
-		struct net_device_stats *stats = &priv->netdev->stats;
-
-		stats->tx_packets++;
-		stats->tx_bytes += can_fd_dlc2len(context->dlc);
-	}
 
 	spin_lock_irqsave(&priv->tx_contexts_lock, irq_flags);
 
-	can_get_echo_skb(priv->netdev, context->echo_index, NULL);
+	len = can_get_echo_skb(priv->netdev, context->echo_index, NULL);
 	context->echo_index = dev->max_tx_urbs;
 	--priv->active_tx_contexts;
 	netif_wake_queue(priv->netdev);
 
 	spin_unlock_irqrestore(&priv->tx_contexts_lock, irq_flags);
+
+	if (!one_shot_fail && !is_err_frame) {
+		struct net_device_stats *stats = &priv->netdev->stats;
+
+		stats->tx_packets++;
+		stats->tx_bytes += len;
+	}
 }
 
 static void kvaser_usb_hydra_rx_msg_std(const struct kvaser_usb *dev,
@@ -1373,8 +1375,8 @@ static void kvaser_usb_hydra_handle_cmd(const struct kvaser_usb *dev,
 
 static void *
 kvaser_usb_hydra_frame_to_cmd_ext(const struct kvaser_usb_net_priv *priv,
-				  const struct sk_buff *skb, int *frame_len,
-				  int *cmd_len, u16 transid)
+				  const struct sk_buff *skb, int *cmd_len,
+				  u16 transid)
 {
 	struct kvaser_usb *dev = priv->dev;
 	struct kvaser_cmd_ext *cmd;
@@ -1386,8 +1388,6 @@ kvaser_usb_hydra_frame_to_cmd_ext(const struct kvaser_usb_net_priv *priv,
 	u32 kcan_id;
 	u32 kcan_header;
 
-	*frame_len = nbr_of_bytes;
-
 	cmd = kcalloc(1, sizeof(struct kvaser_cmd_ext), GFP_ATOMIC);
 	if (!cmd)
 		return NULL;
@@ -1453,8 +1453,8 @@ kvaser_usb_hydra_frame_to_cmd_ext(const struct kvaser_usb_net_priv *priv,
 
 static void *
 kvaser_usb_hydra_frame_to_cmd_std(const struct kvaser_usb_net_priv *priv,
-				  const struct sk_buff *skb, int *frame_len,
-				  int *cmd_len, u16 transid)
+				  const struct sk_buff *skb, int *cmd_len,
+				  u16 transid)
 {
 	struct kvaser_usb *dev = priv->dev;
 	struct kvaser_cmd *cmd;
@@ -1462,8 +1462,6 @@ kvaser_usb_hydra_frame_to_cmd_std(const struct kvaser_usb_net_priv *priv,
 	u32 flags;
 	u32 id;
 
-	*frame_len = cf->len;
-
 	cmd = kcalloc(1, sizeof(struct kvaser_cmd), GFP_ATOMIC);
 	if (!cmd)
 		return NULL;
@@ -1497,7 +1495,7 @@ kvaser_usb_hydra_frame_to_cmd_std(const struct kvaser_usb_net_priv *priv,
 	cmd->tx_can.id = cpu_to_le32(id);
 	cmd->tx_can.flags = flags;
 
-	memcpy(cmd->tx_can.data, cf->data, *frame_len);
+	memcpy(cmd->tx_can.data, cf->data, cf->len);
 
 	return cmd;
 }
@@ -2005,17 +2003,17 @@ static void kvaser_usb_hydra_read_bulk_callback(struct kvaser_usb *dev,
 
 static void *
 kvaser_usb_hydra_frame_to_cmd(const struct kvaser_usb_net_priv *priv,
-			      const struct sk_buff *skb, int *frame_len,
-			      int *cmd_len, u16 transid)
+			      const struct sk_buff *skb, int *cmd_len,
+			      u16 transid)
 {
 	void *buf;
 
 	if (priv->dev->card_data.capabilities & KVASER_USB_HYDRA_CAP_EXT_CMD)
-		buf = kvaser_usb_hydra_frame_to_cmd_ext(priv, skb, frame_len,
-							cmd_len, transid);
+		buf = kvaser_usb_hydra_frame_to_cmd_ext(priv, skb, cmd_len,
+							transid);
 	else
-		buf = kvaser_usb_hydra_frame_to_cmd_std(priv, skb, frame_len,
-							cmd_len, transid);
+		buf = kvaser_usb_hydra_frame_to_cmd_std(priv, skb, cmd_len,
+							transid);
 
 	return buf;
 }

drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c

@@ -389,16 +389,14 @@ static const struct kvaser_usb_dev_cfg kvaser_usb_leaf_dev_cfg_32mhz = {
 
 static void *
 kvaser_usb_leaf_frame_to_cmd(const struct kvaser_usb_net_priv *priv,
-			     const struct sk_buff *skb, int *frame_len,
-			     int *cmd_len, u16 transid)
+			     const struct sk_buff *skb, int *cmd_len,
+			     u16 transid)
 {
 	struct kvaser_usb *dev = priv->dev;
 	struct kvaser_cmd *cmd;
 	u8 *cmd_tx_can_flags = NULL;		/* GCC */
 	struct can_frame *cf = (struct can_frame *)skb->data;
 
-	*frame_len = cf->len;
-
 	cmd = kmalloc(sizeof(*cmd), GFP_ATOMIC);
 	if (cmd) {
 		cmd->u.tx_can.tid = transid & 0xff;
@@ -654,12 +652,11 @@ static void kvaser_usb_leaf_tx_acknowledge(const struct kvaser_usb *dev,
 		priv->can.state = CAN_STATE_ERROR_ACTIVE;
 	}
 
-	stats->tx_packets++;
-	stats->tx_bytes += context->dlc;
-
 	spin_lock_irqsave(&priv->tx_contexts_lock, flags);
 
-	can_get_echo_skb(priv->netdev, context->echo_index, NULL);
+	stats->tx_packets++;
+	stats->tx_bytes += can_get_echo_skb(priv->netdev,
+					    context->echo_index, NULL);
 	context->echo_index = dev->max_tx_urbs;
 	--priv->active_tx_contexts;
 	netif_wake_queue(priv->netdev);

drivers/net/can/usb/mcba_usb.c

@@ -64,7 +64,6 @@
 struct mcba_usb_ctx {
 	struct mcba_priv *priv;
 	u32 ndx;
-	u8 dlc;
 	bool can;
 };
 
@@ -184,13 +183,10 @@ static inline struct mcba_usb_ctx *mcba_usb_get_free_ctx(struct mcba_priv *priv,
 			ctx = &priv->tx_context[i];
 			ctx->ndx = i;
 
-			if (cf) {
+			if (cf)
 				ctx->can = true;
-				ctx->dlc = cf->len;
-			} else {
+			else
 				ctx->can = false;
-				ctx->dlc = 0;
-			}
 
 			atomic_dec(&priv->free_ctx_cnt);
 			break;
@@ -236,10 +232,10 @@ static void mcba_usb_write_bulk_callback(struct urb *urb)
 			return;
 
 		netdev->stats.tx_packets++;
-		netdev->stats.tx_bytes += ctx->dlc;
+		netdev->stats.tx_bytes += can_get_echo_skb(netdev, ctx->ndx,
+							   NULL);
 
 		can_led_event(netdev, CAN_LED_EVENT_TX);
-		can_get_echo_skb(netdev, ctx->ndx, NULL);
 	}
 
 	if (urb->status)

drivers/net/can/usb/peak_usb/pcan_usb_core.c

@@ -291,6 +291,7 @@ static void peak_usb_write_bulk_callback(struct urb *urb)
 	struct peak_tx_urb_context *context = urb->context;
 	struct peak_usb_device *dev;
 	struct net_device *netdev;
+	int tx_bytes;
 
 	BUG_ON(!context);
 
@@ -305,10 +306,6 @@ static void peak_usb_write_bulk_callback(struct urb *urb)
 	/* check tx status */
 	switch (urb->status) {
 	case 0:
-		/* transmission complete */
-		netdev->stats.tx_packets++;
-		netdev->stats.tx_bytes += context->data_len;
-
 		/* prevent tx timeout */
 		netif_trans_update(netdev);
 		break;
@@ -327,12 +324,17 @@ static void peak_usb_write_bulk_callback(struct urb *urb)
 	}
 
 	/* should always release echo skb and corresponding context */
-	can_get_echo_skb(netdev, context->echo_index, NULL);
+	tx_bytes = can_get_echo_skb(netdev, context->echo_index, NULL);
 	context->echo_index = PCAN_USB_MAX_TX_URBS;
 
-	/* do wakeup tx queue in case of success only */
-	if (!urb->status)
+	if (!urb->status) {
+		/* transmission complete */
+		netdev->stats.tx_packets++;
+		netdev->stats.tx_bytes += tx_bytes;
+
+		/* do wakeup tx queue in case of success only */
 		netif_wake_queue(netdev);
+	}
 }
 
 /*
@@ -344,7 +346,6 @@ static netdev_tx_t peak_usb_ndo_start_xmit(struct sk_buff *skb,
 	struct peak_usb_device *dev = netdev_priv(netdev);
 	struct peak_tx_urb_context *context = NULL;
 	struct net_device_stats *stats = &netdev->stats;
-	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
 	struct urb *urb;
 	u8 *obuf;
 	int i, err;
@@ -378,9 +379,6 @@ static netdev_tx_t peak_usb_ndo_start_xmit(struct sk_buff *skb,
 
 	context->echo_index = i;
 
-	/* Note: this works with CANFD frames too */
-	context->data_len = cfd->len;
-
 	usb_anchor_urb(urb, &dev->tx_submitted);
 
 	can_put_echo_skb(skb, netdev, context->echo_index, 0);

drivers/net/can/usb/peak_usb/pcan_usb_core.h

@@ -99,7 +99,6 @@ struct peak_time_ref {
 struct peak_tx_urb_context {
 	struct peak_usb_device *dev;
 	u32 echo_index;
-	u8 data_len;
 	struct urb *urb;
 };
 

drivers/net/can/usb/ucan.c

@@ -259,7 +259,6 @@ struct ucan_priv;
 /* Context Information for transmission URBs */
 struct ucan_urb_context {
 	struct ucan_priv *up;
-	u8 dlc;
 	bool allocated;
 };
 
@@ -637,7 +636,7 @@ static void ucan_tx_complete_msg(struct ucan_priv *up,
 {
 	unsigned long flags;
 	u16 count, i;
-	u8 echo_index, dlc;
+	u8 echo_index;
 	u16 len = le16_to_cpu(m->len);
 
 	struct ucan_urb_context *context;
@@ -661,7 +660,6 @@ static void ucan_tx_complete_msg(struct ucan_priv *up,
 
 		/* gather information from the context */
 		context = &up->context_array[echo_index];
-		dlc = READ_ONCE(context->dlc);
 
 		/* Release context and restart queue if necessary.
 		 * Also check if the context was allocated
@@ -674,8 +672,8 @@ static void ucan_tx_complete_msg(struct ucan_priv *up,
 		    UCAN_TX_COMPLETE_SUCCESS) {
 			/* update statistics */
 			up->netdev->stats.tx_packets++;
-			up->netdev->stats.tx_bytes += dlc;
-			can_get_echo_skb(up->netdev, echo_index, NULL);
+			up->netdev->stats.tx_bytes +=
+				can_get_echo_skb(up->netdev, echo_index, NULL);
 		} else {
 			up->netdev->stats.tx_dropped++;
 			can_free_echo_skb(up->netdev, echo_index, NULL);
@@ -1089,8 +1087,6 @@ static struct urb *ucan_prepare_tx_urb(struct ucan_priv *up,
 	}
 	m->len = cpu_to_le16(mlen);
 
-	context->dlc = cf->len;
-
 	m->subtype = echo_index;
 
 	/* build the urb */

drivers/net/can/usb/usb_8dev.c

@@ -114,7 +114,6 @@ struct usb_8dev_tx_urb_context {
 	struct usb_8dev_priv *priv;
 
 	u32 echo_index;
-	u8 dlc;
 };
 
 /* Structure to hold all of our device specific stuff */
@@ -581,9 +580,7 @@ static void usb_8dev_write_bulk_callback(struct urb *urb)
 			 urb->status);
 
 	netdev->stats.tx_packets++;
-	netdev->stats.tx_bytes += context->dlc;
-
-	can_get_echo_skb(netdev, context->echo_index, NULL);
+	netdev->stats.tx_bytes += can_get_echo_skb(netdev, context->echo_index, NULL);
 
 	can_led_event(netdev, CAN_LED_EVENT_TX);
 
@@ -654,7 +651,6 @@ static netdev_tx_t usb_8dev_start_xmit(struct sk_buff *skb,
 
 	context->priv = priv;
 	context->echo_index = i;
-	context->dlc = cf->len;
 
 	usb_fill_bulk_urb(urb, priv->udev,
 			  usb_sndbulkpipe(priv->udev, USB_8DEV_ENDP_DATA_TX),

drivers/net/can/vcan.c

@@ -87,13 +87,14 @@ static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
 {
 	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
 	struct net_device_stats *stats = &dev->stats;
-	int loop;
+	int loop, len;
 
 	if (can_dropped_invalid_skb(dev, skb))
 		return NETDEV_TX_OK;
 
+	len = cfd->can_id & CAN_RTR_FLAG ? 0 : cfd->len;
 	stats->tx_packets++;
-	stats->tx_bytes += cfd->len;
+	stats->tx_bytes += len;
 
 	/* set flag whether this packet has to be looped back */
 	loop = skb->pkt_type == PACKET_LOOPBACK;
@@ -105,7 +106,7 @@ static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
 			 * CAN core already did the echo for us
 			 */
 			stats->rx_packets++;
-			stats->rx_bytes += cfd->len;
+			stats->rx_bytes += len;
 		}
 		consume_skb(skb);
 		return NETDEV_TX_OK;

drivers/net/can/vxcan.c

@@ -62,7 +62,7 @@ static netdev_tx_t vxcan_xmit(struct sk_buff *skb, struct net_device *dev)
 	skb->dev        = peer;
 	skb->ip_summed  = CHECKSUM_UNNECESSARY;
 
-	len = cfd->len;
+	len = cfd->can_id & CAN_RTR_FLAG ? 0 : cfd->len;
 	if (netif_rx_ni(skb) == NET_RX_SUCCESS) {
 		srcstats->tx_packets++;
 		srcstats->tx_bytes += len;

include/linux/can/skb.h

@@ -21,8 +21,9 @@ int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 		     unsigned int idx, unsigned int frame_len);
 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx,
 				   u8 *len_ptr, unsigned int *frame_len_ptr);
-unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx,
-			      unsigned int *frame_len_ptr);
+unsigned int __must_check can_get_echo_skb(struct net_device *dev,
+					   unsigned int idx,
+					   unsigned int *frame_len_ptr);
 void can_free_echo_skb(struct net_device *dev, unsigned int idx,
 		       unsigned int *frame_len_ptr);
 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf);