diff mbox series

[net-next,v3,1/4] net: hdlc_fr: Simpify fr_rx by using "goto rx_drop" to drop frames

Message ID 20201028184310.7017-2-xie.he.0141@gmail.com (mailing list archive)
State Not Applicable
Delegated to: Netdev Maintainers
Headers show
Series net: hdlc_fr: Add support for any Ethertype | expand

Commit Message

Xie He Oct. 28, 2020, 6:43 p.m. UTC
When the fr_rx function drops a received frame (because the protocol type
is not supported, or because the PVC virtual device that corresponds to
the DLCI number and the protocol type doesn't exist), the function frees
the skb and returns.

The code for freeing the skb and returning is repeated several times, this
patch uses "goto rx_drop" to replace them so that the code looks cleaner.

Also add code to increase the stats.rx_dropped count whenever we drop a
frame.

Cc: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
---
 drivers/net/wan/hdlc_fr.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

Comments

Willem de Bruijn Oct. 29, 2020, 4:59 p.m. UTC | #1
On Wed, Oct 28, 2020 at 6:01 PM Xie He <xie.he.0141@gmail.com> wrote:
>
> When the fr_rx function drops a received frame (because the protocol type
> is not supported, or because the PVC virtual device that corresponds to
> the DLCI number and the protocol type doesn't exist), the function frees
> the skb and returns.
>
> The code for freeing the skb and returning is repeated several times, this
> patch uses "goto rx_drop" to replace them so that the code looks cleaner.
>
> Also add code to increase the stats.rx_dropped count whenever we drop a
> frame.
>
> Cc: Krzysztof Halasa <khc@pm.waw.pl>
> Signed-off-by: Xie He <xie.he.0141@gmail.com>
> ---
>  drivers/net/wan/hdlc_fr.c | 16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c
> index 409e5a7ad8e2..c774eff44534 100644
> --- a/drivers/net/wan/hdlc_fr.c
> +++ b/drivers/net/wan/hdlc_fr.c
> @@ -904,8 +904,7 @@ static int fr_rx(struct sk_buff *skb)
>                 netdev_info(frad, "No PVC for received frame's DLCI %d\n",
>                             dlci);
>  #endif
> -               dev_kfree_skb_any(skb);
> -               return NET_RX_DROP;
> +               goto rx_drop;
>         }
>
>         if (pvc->state.fecn != fh->fecn) {
> @@ -963,14 +962,12 @@ static int fr_rx(struct sk_buff *skb)
>                 default:
>                         netdev_info(frad, "Unsupported protocol, OUI=%x PID=%x\n",
>                                     oui, pid);
> -                       dev_kfree_skb_any(skb);
> -                       return NET_RX_DROP;
> +                       goto rx_drop;
>                 }
>         } else {
>                 netdev_info(frad, "Unsupported protocol, NLPID=%x length=%i\n",
>                             data[3], skb->len);
> -               dev_kfree_skb_any(skb);
> -               return NET_RX_DROP;
> +               goto rx_drop;
>         }
>
>         if (dev) {
> @@ -982,12 +979,13 @@ static int fr_rx(struct sk_buff *skb)
>                 netif_rx(skb);
>                 return NET_RX_SUCCESS;
>         } else {
> -               dev_kfree_skb_any(skb);
> -               return NET_RX_DROP;
> +               goto rx_drop;
>         }
>
> - rx_error:
> +rx_error:
>         frad->stats.rx_errors++; /* Mark error */
> +rx_drop:
> +       frad->stats.rx_dropped++;
>         dev_kfree_skb_any(skb);
>         return NET_RX_DROP;

This does change rx_dropped count on errors. Not sure how important
that is. But perhaps good to call out in the commit explicitly if it's
intentional.
Xie He Oct. 29, 2020, 11:10 p.m. UTC | #2
On Thu, Oct 29, 2020 at 10:00 AM Willem de Bruijn
<willemdebruijn.kernel@gmail.com> wrote:
>
> This does change rx_dropped count on errors. Not sure how important
> that is. But perhaps good to call out in the commit explicitly if it's
> intentional.

Yes, this is intentional, because I think we need to count it as a
"drop" whenever we drop an skb. I'll note this explicitly in the
commit message in the next versions of the patch. Thanks!
diff mbox series

Patch

diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c
index 409e5a7ad8e2..c774eff44534 100644
--- a/drivers/net/wan/hdlc_fr.c
+++ b/drivers/net/wan/hdlc_fr.c
@@ -904,8 +904,7 @@  static int fr_rx(struct sk_buff *skb)
 		netdev_info(frad, "No PVC for received frame's DLCI %d\n",
 			    dlci);
 #endif
-		dev_kfree_skb_any(skb);
-		return NET_RX_DROP;
+		goto rx_drop;
 	}
 
 	if (pvc->state.fecn != fh->fecn) {
@@ -963,14 +962,12 @@  static int fr_rx(struct sk_buff *skb)
 		default:
 			netdev_info(frad, "Unsupported protocol, OUI=%x PID=%x\n",
 				    oui, pid);
-			dev_kfree_skb_any(skb);
-			return NET_RX_DROP;
+			goto rx_drop;
 		}
 	} else {
 		netdev_info(frad, "Unsupported protocol, NLPID=%x length=%i\n",
 			    data[3], skb->len);
-		dev_kfree_skb_any(skb);
-		return NET_RX_DROP;
+		goto rx_drop;
 	}
 
 	if (dev) {
@@ -982,12 +979,13 @@  static int fr_rx(struct sk_buff *skb)
 		netif_rx(skb);
 		return NET_RX_SUCCESS;
 	} else {
-		dev_kfree_skb_any(skb);
-		return NET_RX_DROP;
+		goto rx_drop;
 	}
 
- rx_error:
+rx_error:
 	frad->stats.rx_errors++; /* Mark error */
+rx_drop:
+	frad->stats.rx_dropped++;
 	dev_kfree_skb_any(skb);
 	return NET_RX_DROP;
 }