net: dsa: make dsa_port_supports_hwtstamp() construct a fake ifreq

dsa_master_ioctl() is in the process of getting converted to a different
API, where we won't have access to a struct ifreq * anymore, but rather,
to a struct kernel_hwtstamp_config.

Since ds->ops->port_hwtstamp_get() still uses struct ifreq *, this
creates a difficult situation where we have to make up such a dummy
pointer.

The conversion is a bit messy, because it forces a "good" implementation
of ds->ops->port_hwtstamp_get() to return -EFAULT in copy_to_user()
because of the NULL ifr->ifr_data pointer. However, it works, and it is
only a transient step until ds->ops->port_hwtstamp_get() gets converted
to the new API which passes struct kernel_hwtstamp_config and does not
call copy_to_user().

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/dsa/master.c b/net/dsa/master.c
index 22d3f16..e397641 100644 (file)
--- a/net/dsa/master.c
+++ b/net/dsa/master.c
@@ -212,7 +212,7 @@ 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 (dsa_port_supports_hwtstamp(dp, ifr))
+                       if (dsa_port_supports_hwtstamp(dp))
                                return -EBUSY;
                break;
        }

diff --git a/net/dsa/port.c b/net/dsa/port.c
index 15cee17..71ba305 100644 (file)
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -114,19 +114,21 @@ 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)
+bool dsa_port_supports_hwtstamp(struct dsa_port *dp)
 {
        struct dsa_switch *ds = dp->ds;
+       struct ifreq ifr = {};
        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.
+        * Since we can't cook up a complete ioctl request structure, this will
+        * fail in copy_to_user() with -EFAULT, which hopefully is enough to
+        * detect a valid implementation.
         */
-       err = ds->ops->port_hwtstamp_get(ds, dp->index, ifr);
+       err = ds->ops->port_hwtstamp_get(ds, dp->index, &ifr);
        return err != -EOPNOTSUPP;
 }
 

diff --git a/net/dsa/port.h b/net/dsa/port.h
index 9c21866..dc81251 100644 (file)
--- a/net/dsa/port.h
+++ b/net/dsa/port.h
@@ -15,7 +15,7 @@ struct switchdev_obj_port_mdb;
 struct switchdev_vlan_msti;
 struct phy_device;
 
-bool dsa_port_supports_hwtstamp(struct dsa_port *dp, struct ifreq *ifr);
+bool dsa_port_supports_hwtstamp(struct dsa_port *dp);
 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);