From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Cc: linux-kernel@vger.kernel.org,
Amarula patchwork <linux-amarula@amarulasolutions.com>,
michael@amarulasolutions.com,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Wolfgang Grandegger <wg@grandegger.com>,
linux-can@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH v2 03/13] can: slcan: use the alloc_can_skb() helper
Date: Thu, 9 Jun 2022 10:07:24 +0200 [thread overview]
Message-ID: <20220609080724.z2ouwivtgu36b423@pengutronix.de> (raw)
In-Reply-To: <20220608165116.1575390-4-dario.binacchi@amarulasolutions.com>
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On 08.06.2022 18:51:06, Dario Binacchi wrote:
> It is used successfully by most (if not all) CAN device drivers. It
> allows to remove replicated code.
>
> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
>
> ---
>
> Changes in v2:
> - Put the data into the allocated skb directly instead of first
> filling the "cf" on the stack and then doing a memcpy().
>
> drivers/net/can/slcan.c | 69 +++++++++++++++++++----------------------
> 1 file changed, 32 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c
> index 6162a9c21672..5d87e25e2285 100644
> --- a/drivers/net/can/slcan.c
> +++ b/drivers/net/can/slcan.c
> @@ -54,6 +54,7 @@
> #include <linux/kernel.h>
> #include <linux/workqueue.h>
> #include <linux/can.h>
> +#include <linux/can/dev.h>
> #include <linux/can/skb.h>
> #include <linux/can/can-ml.h>
>
> @@ -143,85 +144,79 @@ static struct net_device **slcan_devs;
> static void slc_bump(struct slcan *sl)
> {
> struct sk_buff *skb;
> - struct can_frame cf;
> + struct can_frame *cf;
> int i, tmp;
> u32 tmpid;
> char *cmd = sl->rbuff;
>
> - memset(&cf, 0, sizeof(cf));
> + skb = alloc_can_skb(sl->dev, &cf);
> + if (unlikely(!skb)) {
> + sl->dev->stats.rx_dropped++;
> + return;
> + }
>
> switch (*cmd) {
> case 'r':
> - cf.can_id = CAN_RTR_FLAG;
> + cf->can_id = CAN_RTR_FLAG;
> fallthrough;
> case 't':
> /* store dlc ASCII value and terminate SFF CAN ID string */
> - cf.len = 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;
> break;
> case 'R':
> - cf.can_id = CAN_RTR_FLAG;
> + cf->can_id = CAN_RTR_FLAG;
> fallthrough;
> case 'T':
> - cf.can_id |= CAN_EFF_FLAG;
> + cf->can_id |= CAN_EFF_FLAG;
> /* store dlc ASCII value and terminate EFF CAN ID string */
> - cf.len = 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;
> break;
> default:
> - return;
> + goto decode_failed;
> }
>
> if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid))
> - return;
> + goto decode_failed;
>
> - cf.can_id |= tmpid;
> + cf->can_id |= tmpid;
>
> /* get len from sanitized ASCII value */
> - if (cf.len >= '0' && cf.len < '9')
> - cf.len -= '0';
> + if (cf->len >= '0' && cf->len < '9')
> + cf->len -= '0';
> else
> - return;
> + goto decode_failed;
>
> /* 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.len; i++) {
> + if (!(cf->can_id & CAN_RTR_FLAG)) {
> + for (i = 0; i < cf->len; i++) {
> tmp = hex_to_bin(*cmd++);
> if (tmp < 0)
> - return;
> - cf.data[i] = (tmp << 4);
> + goto decode_failed;
> +
> + cf->data[i] = (tmp << 4);
> tmp = hex_to_bin(*cmd++);
> if (tmp < 0)
> - return;
> - cf.data[i] |= tmp;
> + goto decode_failed;
> +
> + cf->data[i] |= tmp;
> }
> }
>
> - skb = dev_alloc_skb(sizeof(struct can_frame) +
> - sizeof(struct can_skb_priv));
> - if (!skb)
> - return;
> -
> - skb->dev = sl->dev;
> - skb->protocol = htons(ETH_P_CAN);
> - skb->pkt_type = PACKET_BROADCAST;
> - skb->ip_summed = CHECKSUM_UNNECESSARY;
> -
> - can_skb_reserve(skb);
> - can_skb_prv(skb)->ifindex = sl->dev->ifindex;
> - can_skb_prv(skb)->skbcnt = 0;
> -
> - skb_put_data(skb, &cf, sizeof(struct can_frame));
> -
> sl->dev->stats.rx_packets++;
> - if (!(cf.can_id & CAN_RTR_FLAG))
> - sl->dev->stats.rx_bytes += cf.len;
> + if (!(cf->can_id & CAN_RTR_FLAG))
> + sl->dev->stats.rx_bytes += cf->len;
>
> netif_rx(skb);
> + return;
> +
> +decode_failed:
> + dev_kfree_skb(skb);
Can you increase an error counter in this situation, too?
Marc
> }
>
> /* parse tty input stream */
> --
> 2.32.0
>
>
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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next prev parent reply other threads:[~2022-06-09 8:07 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-08 16:51 [PATCH v2 00/13] can: slcan: extend supported features Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 01/13] can: slcan: use the BIT() helper Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 02/13] can: slcan: use netdev helpers to print out messages Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 03/13] can: slcan: use the alloc_can_skb() helper Dario Binacchi
2022-06-09 8:07 ` Marc Kleine-Budde [this message]
2022-06-08 16:51 ` [PATCH v2 04/13] can: slcan: use CAN network device driver API Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 05/13] can: slcan: simplify the device de-allocation Dario Binacchi
2022-06-08 20:38 ` Oliver Hartkopp
2022-06-11 10:46 ` Dario Binacchi
2022-06-12 16:23 ` Max Staudt
2022-06-12 17:13 ` Oliver Hartkopp
2022-06-12 21:20 ` Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 06/13] can: slcan: allow to send commands to the adapter Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 07/13] can: slcan: set bitrate by CAN device driver API Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 08/13] can: slcan: send the open command to the adapter Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 09/13] can: slcan: send the close " Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 10/13] can: slcan: move driver into separate sub directory Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 11/13] can: slcan: add ethtool support to reset adapter errors Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 12/13] can: slcan: extend the protocol with error info Dario Binacchi
2022-06-08 16:51 ` [PATCH v2 13/13] can: slcan: extend the protocol with CAN state info Dario Binacchi
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