[PATCH net-next v2 3/5] net: phylink: allow mac_select_pcs() to remove a PCS

["Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>]

phylink has historically not permitted a PCS to be removed. An attempt
to permit this with phylink_set_pcs() resulted in comments indicating
that there was no need for this. This behaviour has been propagated
forward to the mac_select_pcs() approach as it was believed from these
comments that changing this would be NAK'd.

However, with mac_select_pcs(), it takes more code and thus complexity
to maintain this behaviour, which can - and in this case has - resulted
in a bug. If mac_select_pcs() returns NULL for a particular interface
type, but there is already a PCS in-use, then we skip the pcs_validate()
method, but continue using the old PCS. Also, it wouldn't be expected
behaviour by implementers of mac_select_pcs().

Allow this by removing this old unnecessary restriction.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/phy/phylink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 24a3144e870a..aa1139efc7e4 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -1184,7 +1184,7 @@ static void phylink_major_config(struct phylink *pl, bool restart,
 			return;
 		}
 
-		pcs_changed = pcs && pl->pcs != pcs;
+		pcs_changed = pl->pcs != pcs;
 	}
 
 	phylink_pcs_poll_stop(pl);
-- 
2.30.2