On Mon, Apr 26, 2021 at 05:37:58PM +0800, Yangbo Lu wrote:
> Free skb->cb usage in core driver and let device drivers decide to
> use or not. The reason having a DSA_SKB_CB(skb)->clone was because
> dsa_skb_tx_timestamp() which may set the clone pointer was called
> before p->xmit() which would use the clone if any, and the device
> driver has no way to initialize the clone pointer.
>
> Although for now putting memset(skb->cb, 0, 48) at beginning of
> dsa_slave_xmit() by this patch is not very good, there is still way
> to improve this. Otherwise, some other new features, like one-step
> timestamp which needs a flag of skb marked in dsa_skb_tx_timestamp(),
> and handles as one-step timestamp in p->xmit() will face same
> situation.
>
> Signed-off-by: Yangbo Lu <yangbo.lu@xxxxxxx>
> ---
> Changes for v2:
> - Added this patch.
> ---
> drivers/net/dsa/ocelot/felix.c | 1 +
> drivers/net/dsa/sja1105/sja1105_main.c | 2 +-
> drivers/net/dsa/sja1105/sja1105_ptp.c | 4 +++-
> drivers/net/ethernet/mscc/ocelot.c | 6 +++---
> drivers/net/ethernet/mscc/ocelot_net.c | 2 +-
> include/linux/dsa/sja1105.h | 3 ++-
> include/net/dsa.h | 14 --------------
> include/soc/mscc/ocelot.h | 8 ++++++++
> net/dsa/slave.c | 3 +--
> net/dsa/tag_ocelot.c | 8 ++++----
> net/dsa/tag_ocelot_8021q.c | 8 ++++----
> 11 files changed, 28 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
> index d679f023dc00..8980d56ee793 100644
> --- a/drivers/net/dsa/ocelot/felix.c
> +++ b/drivers/net/dsa/ocelot/felix.c
> @@ -1403,6 +1403,7 @@ static bool felix_txtstamp(struct dsa_switch *ds, int port,
>
> if (ocelot->ptp && ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
> ocelot_port_add_txtstamp_skb(ocelot, port, clone);
> + OCELOT_SKB_CB(skb)->clone = clone;
> return true;
> }
>
Uh-oh, this patch fails to build:
In file included from ./include/soc/mscc/ocelot_vcap.h:9:0,
from drivers/net/dsa/ocelot/felix.c:9:
drivers/net/dsa/ocelot/felix.c: In function ‘felix_txtstamp’:
drivers/net/dsa/ocelot/felix.c:1406:17: error: ‘skb’ undeclared (first use in this function)
OCELOT_SKB_CB(skb)->clone = clone;
^
./include/soc/mscc/ocelot.h:698:29: note: in definition of macro ‘OCELOT_SKB_CB’
((struct ocelot_skb_cb *)((skb)->cb))
^~~
drivers/net/dsa/ocelot/felix.c:1406:17: note: each undeclared identifier is reported only once for each function it appears in
OCELOT_SKB_CB(skb)->clone = clone;
^
./include/soc/mscc/ocelot.h:698:29: note: in definition of macro ‘OCELOT_SKB_CB’
((struct ocelot_skb_cb *)((skb)->cb))
^~~
It depends on changes made in patch 3.
