This is a note to let you know that I've just added the patch titled
net: dsa: make dsa_master_ioctl() see through port_hwtstamp_get() shims
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-dsa-make-dsa_master_ioctl-see-through-port_hwtst.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 83730ebd680280471ccbf9f92bc797a6b130350f
Author: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Date: Fri Nov 11 23:10:20 2022 +0200
net: dsa: make dsa_master_ioctl() see through port_hwtstamp_get() shims
[ Upstream commit ed1fe1bebe18884b11e5536b5ac42e3a48960835 ]
There are multi-generational drivers like mv88e6xxx which have code like
this:
int mv88e6xxx_port_hwtstamp_get(struct dsa_switch *ds, int port,
struct ifreq *ifr)
{
if (!chip->info->ptp_support)
return -EOPNOTSUPP;
...
}
DSA wants to deny PTP timestamping on the master if the switch supports
timestamping too. However it currently relies on the presence of the
port_hwtstamp_get() callback to determine PTP capability, and this
clearly does not work in that case (method is present but returns
-EOPNOTSUPP).
We should not deny PTP on the DSA master for those switches which truly
do not support hardware timestamping.
Create a dsa_port_supports_hwtstamp() method which actually probes for
support by calling port_hwtstamp_get() and seeing whether that returned
-EOPNOTSUPP or not.
Fixes: f685e609a301 ("net: dsa: Deny PTP on master if switch supports it")
Link: https://patchwork.kernel.org/project/netdevbpf/patch/20221110124345.3901389-1-festevam@xxxxxxxxx/
Reported-by: Fabio Estevam <festevam@xxxxxxxxx>
Reported-by: Steffen Bätz <steffen@xxxxxxxxxxxx>
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Tested-by: Fabio Estevam <festevam@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index a5c9bc7b66c6..e91265434354 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -198,6 +198,7 @@ static inline struct net_device *dsa_master_find_slave(struct net_device *dev,
}
/* port.c */
+bool dsa_port_supports_hwtstamp(struct dsa_port *dp, struct ifreq *ifr);
void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp,
const struct dsa_device_ops *tag_ops);
int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age);
diff --git a/net/dsa/master.c b/net/dsa/master.c
index e8e19857621b..69ec510abe83 100644
--- a/net/dsa/master.c
+++ b/net/dsa/master.c
@@ -204,8 +204,7 @@ static int dsa_master_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
* switch in the tree that is PTP capable.
*/
list_for_each_entry(dp, &dst->ports, list)
- if (dp->ds->ops->port_hwtstamp_get ||
- dp->ds->ops->port_hwtstamp_set)
+ if (dsa_port_supports_hwtstamp(dp, ifr))
return -EBUSY;
break;
}
diff --git a/net/dsa/port.c b/net/dsa/port.c
index a21015d6bd36..31e8a7a8c3e6 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -75,6 +75,22 @@ static bool dsa_port_can_configure_learning(struct dsa_port *dp)
return !err;
}
+bool dsa_port_supports_hwtstamp(struct dsa_port *dp, struct ifreq *ifr)
+{
+ struct dsa_switch *ds = dp->ds;
+ int err;
+
+ if (!ds->ops->port_hwtstamp_get || !ds->ops->port_hwtstamp_set)
+ return false;
+
+ /* "See through" shim implementations of the "get" method.
+ * This will clobber the ifreq structure, but we will either return an
+ * error, or the master will overwrite it with proper values.
+ */
+ err = ds->ops->port_hwtstamp_get(ds, dp->index, ifr);
+ return err != -EOPNOTSUPP;
+}
+
int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age)
{
struct dsa_switch *ds = dp->ds;
