can: replace can_dlc as variable/element for payload length

The naming of can_dlc as element of struct can_frame and also as variable
name is misleading as it claims to be a 'data length CODE' but in reality
it always was a plain data length.

With the indroduction of a new 'len' element in struct can_frame we can now
remove can_dlc as name and make clear which of the former uses was a plain
length (-> 'len') or a data length code (-> 'dlc') value.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20201120100444.3199-1-socketcan@hartkopp.net
[mkl: gs_usb: keep struct gs_host_frame::can_dlc as is]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c
index b4a39f0..a1bd1be 100644
--- a/drivers/net/can/slcan.c
+++ b/drivers/net/can/slcan.c
@@ -106,8 +106,8 @@ static struct net_device **slcan_devs;
 
 /*
  * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
- * frame format) a data length code (can_dlc) which can be from 0 to 8
- * and up to <can_dlc> data bytes as payload.
+ * frame format) a data length code (len) which can be from 0 to 8
+ * and up to <len> data bytes as payload.
  * Additionally a CAN frame may become a remote transmission frame if the
  * RTR-bit is set. This causes another ECU to send a CAN frame with the
  * given can_id.
@@ -128,10 +128,10 @@ static struct net_device **slcan_devs;
  *
  * Examples:
  *
- * t1230 : can_id 0x123, can_dlc 0, no data
- * t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33
- * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55
- * r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request
+ * t1230 : can_id 0x123, len 0, no data
+ * t4563112233 : can_id 0x456, len 3, data 0x11 0x22 0x33
+ * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, len 2, data 0xAA 0x55
+ * r1230 : can_id 0x123, len 0, no data, remote transmission request
  *
  */
 
@@ -156,7 +156,7 @@ static void slc_bump(struct slcan *sl)
 		fallthrough;
 	case 't':
 		/* store dlc ASCII value and terminate SFF CAN ID string */
-		cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN];
+		cf.len = sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN];
 		sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN] = 0;
 		/* point to payload data behind the dlc */
 		cmd += SLC_CMD_LEN + SLC_SFF_ID_LEN + 1;
@@ -167,7 +167,7 @@ static void slc_bump(struct slcan *sl)
 	case 'T':
 		cf.can_id |= CAN_EFF_FLAG;
 		/* store dlc ASCII value and terminate EFF CAN ID string */
-		cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN];
+		cf.len = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN];
 		sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN] = 0;
 		/* point to payload data behind the dlc */
 		cmd += SLC_CMD_LEN + SLC_EFF_ID_LEN + 1;
@@ -181,15 +181,15 @@ static void slc_bump(struct slcan *sl)
 
 	cf.can_id |= tmpid;
 
-	/* get can_dlc from sanitized ASCII value */
-	if (cf.can_dlc >= '0' && cf.can_dlc < '9')
-		cf.can_dlc -= '0';
+	/* get len from sanitized ASCII value */
+	if (cf.len >= '0' && cf.len < '9')
+		cf.len -= '0';
 	else
 		return;
 
 	/* RTR frames may have a dlc > 0 but they never have any data bytes */
 	if (!(cf.can_id & CAN_RTR_FLAG)) {
-		for (i = 0; i < cf.can_dlc; i++) {
+		for (i = 0; i < cf.len; i++) {
 			tmp = hex_to_bin(*cmd++);
 			if (tmp < 0)
 				return;
@@ -218,7 +218,7 @@ static void slc_bump(struct slcan *sl)
 	skb_put_data(skb, &cf, sizeof(struct can_frame));
 
 	sl->dev->stats.rx_packets++;
-	sl->dev->stats.rx_bytes += cf.can_dlc;
+	sl->dev->stats.rx_bytes += cf.len;
 	netif_rx_ni(skb);
 }
 
@@ -282,11 +282,11 @@ static void slc_encaps(struct slcan *sl, struct can_frame *cf)
 
 	pos += (cf->can_id & CAN_EFF_FLAG) ? SLC_EFF_ID_LEN : SLC_SFF_ID_LEN;
 
-	*pos++ = cf->can_dlc + '0';
+	*pos++ = cf->len + '0';
 
 	/* RTR frames may have a dlc > 0 but they never have any data bytes */
 	if (!(cf->can_id & CAN_RTR_FLAG)) {
-		for (i = 0; i < cf->can_dlc; i++)
+		for (i = 0; i < cf->len; i++)
 			pos = hex_byte_pack_upper(pos, cf->data[i]);
 	}
 
@@ -304,7 +304,7 @@ 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->can_dlc;
+	sl->dev->stats.tx_bytes += cf->len;
 }
 
 /* Write out any remaining transmit buffer. Scheduled when tty is writable */