iflib: Fix detach of pseudo interfaces

In commit 38bfc6dee33b we added an IFDI_DETACH() call to
iflib_pseudo_deregister() since it looked like it was missing.  One is
present in the error-handling path of iflib_pseudo_register().  However,
the detach actually comes from the DEVICE_DETACH() method for the
above-mentioned device_t, so now we're calling IFDI_DETACH() twice when
destroying a pseudo interface.

Fix the problem by not calling IFDI_DETACH() from the device detach
routine.  This way we can ensure that iflib de-initialization always
happens in a consistent order.  It also ensures that you can't do silly
things like "devctl detach <pseudo ifnet>", which would previously
detach the driver without tearing down the corresponding ifnet.

PR:		253541
Reviewed by:	erj
MFC after:	1 week
Fixes:		38bfc6dee33b
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D28774

1 files changed, 3 insertions, 5 deletions

diff --git a/sys/net/iflib_clone.c b/sys/net/iflib_clone.c
index dc4ccbee659f..975873c4a19c 100644
--- a/sys/net/iflib_clone.c
+++ b/sys/net/iflib_clone.c
@@ -81,13 +81,11 @@ int
 iflib_pseudo_detach(device_t dev)
 {
 	if_ctx_t ctx;
-	uint32_t ifc_flags;
 
 	ctx = device_get_softc(dev);
-	ifc_flags = iflib_get_flags(ctx);
-	if ((ifc_flags & IFC_INIT_DONE) == 0)
-		return (0);
-	return (IFDI_DETACH(ctx));
+	if ((iflib_get_flags(ctx) & IFC_IN_DETACH) == 0)
+		return (EBUSY);
+	return (0);
 }
 
 static device_t iflib_pseudodev;