[RFC PATCH net-next 3/3] net: dsa: allow the phy_connect() call to return -EPROBE_DEFER

Currently DSA ignores any errors coming from dsa_port_setup(), and this
includes:

dsa_port_setup
-> dsa_slave_create
   -> dsa_slave_phy_setup
      -> phylink_of_phy_connect
         -> ...
            -> phy_attach_direct

This is done such that PHYs present on optional riser cards which are
missing do not cause the entire switch probing to fail.

Now that phy_attach_direct tries harder to probe the specific PHY driver
instead of genphy, it can actually return -EPROBE_DEFER. It makes sense
to treat this error separately, and not just give up. Trigger the normal
error path, unwind the setup done so far, and come back later.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 net/dsa/dsa2.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index e78901d33a10..282bdebac835 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c

@@ -912,6 +912,8 @@ static int dsa_tree_setup_switches(struct dsa_switch_tree *dst)
 
 	list_for_each_entry(dp, &dst->ports, list) {
 		err = dsa_port_setup(dp);
+		if (err == -EPROBE_DEFER)
+			goto teardown;
 		if (err) {
 			dsa_port_devlink_teardown(dp);
 			dp->type = DSA_PORT_TYPE_UNUSED;

-- 
2.25.1