[PATCH net-next] net: dsa: don't call ptp_classify_raw() if switch doesn't provide RX timestamping

[PATCH net-next] net: dsa: don't call ptp_classify_raw() if switch doesn't provide RX timestamping

[Vladimir Oltean]

ptp_classify_raw() is not exactly cheap, since it invokes a BPF program
for every skb in the receive path. For switches which do not provide
ds->ops->port_rxtstamp(), running ptp_classify_raw() provides precisely
nothing, so check for the presence of the function pointer first, since
that is much cheaper.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 net/dsa/tag.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/dsa/tag.c b/net/dsa/tag.c
index 383721e167d6..b2fba1a003ce 100644
--- a/net/dsa/tag.c
+++ b/net/dsa/tag.c
@@ -33,6 +33,9 @@ static bool dsa_skb_defer_rx_timestamp(struct dsa_slave_priv *p,
 	struct dsa_switch *ds = p->dp->ds;
 	unsigned int type;
 
+	if (!ds->ops->port_rxtstamp)
+		return false;
+
 	if (skb_headroom(skb) < ETH_HLEN)
 		return false;
 
@@ -45,10 +48,7 @@ static bool dsa_skb_defer_rx_timestamp(struct dsa_slave_priv *p,
 	if (type == PTP_CLASS_NONE)
 		return false;
 
-	if (likely(ds->ops->port_rxtstamp))
-		return ds->ops->port_rxtstamp(ds, p->dp->index, skb, type);
-
-	return false;
+	return ds->ops->port_rxtstamp(ds, p->dp->index, skb, type);
 }
 
 static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
-- 
2.34.1

Re: [PATCH net-next] net: dsa: don't call ptp_classify_raw() if switch doesn't provide RX timestamping

[Florian Fainelli]

On 12/9/22 09:58, Vladimir Oltean wrote:
> ptp_classify_raw() is not exactly cheap, since it invokes a BPF program
> for every skb in the receive path. For switches which do not provide
> ds->ops->port_rxtstamp(), running ptp_classify_raw() provides precisely
> nothing, so check for the presence of the function pointer first, since
> that is much cheaper.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Re: [PATCH net-next] net: dsa: don't call ptp_classify_raw() if switch doesn't provide RX timestamping

[Kurt Kanzenbach]

[-- Attachment #1: Type: text/plain, Size: 514 bytes --]

On Fri Dec 09 2022, Vladimir Oltean wrote:
> ptp_classify_raw() is not exactly cheap, since it invokes a BPF program
> for every skb in the receive path.

Only if CONFIG_NET_PTP_CLASSIFY is set.

> For switches which do not provide ds->ops->port_rxtstamp(), running
> ptp_classify_raw() provides precisely nothing, so check for the
> presence of the function pointer first, since that is much cheaper.
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 861 bytes --]

Re: [PATCH net-next] net: dsa: don't call ptp_classify_raw() if switch doesn't provide RX timestamping

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Fri,  9 Dec 2022 19:58:40 +0200 you wrote:
> ptp_classify_raw() is not exactly cheap, since it invokes a BPF program
> for every skb in the receive path. For switches which do not provide
> ds->ops->port_rxtstamp(), running ptp_classify_raw() provides precisely
> nothing, so check for the presence of the function pointer first, since
> that is much cheaper.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> 
> [...]

Here is the summary with links:
  - [net-next] net: dsa: don't call ptp_classify_raw() if switch doesn't provide RX timestamping
    https://git.kernel.org/netdev/net-next/c/8f18655c49eb

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html