Unneeded splnet()/splx() in carp(4)

[Martin Pieuchot]

carp(4), as a pseudo-interface, is always executed in the 'softnet'
thread.  Using splnet()/splx() might have been relevant when link-state
handlers where directly executed from hardware interrupt handlers.  But
nowadays everything is run under the NET_LOCK() in a thread context, so
let's get rid of these superfluous splnet()/splx() dances.

ok?

Index: netinet/ip_carp.c
===================================================================
RCS file: /cvs/src/sys/netinet/ip_carp.c,v
retrieving revision 1.302
diff -u -p -r1.302 ip_carp.c
--- netinet/ip_carp.c   20 Feb 2017 06:29:42 -0000      1.302
+++ netinet/ip_carp.c   7 Mar 2017 10:05:08 -0000
@@ -898,7 +898,6 @@ carpdetach(struct carp_softc *sc)
 {
        struct ifnet *ifp0;
        struct carp_if *cif;
-       int s;
 
        carp_del_all_timeouts(sc);
 
@@ -926,7 +925,6 @@ carpdetach(struct carp_softc *sc)
        /* Restore previous input handler. */
        if_ih_remove(ifp0, carp_input, cif);
 
-       s = splnet();
        if (sc->lh_cookie != NULL)
                hook_disestablish(ifp0->if_linkstatehooks, sc->lh_cookie);
 
@@ -938,7 +936,6 @@ carpdetach(struct carp_softc *sc)
                free(cif, M_IFADDR, sizeof(*cif));
        }
        sc->sc_carpdev = NULL;
-       splx(s);
 }
 
 /* Detach an interface from the carp. */
@@ -1680,7 +1677,6 @@ carp_set_ifp(struct carp_softc *sc, stru
        struct carp_if *cif, *ncif = NULL;
        struct carp_softc *vr, *last = NULL, *after = NULL;
        int myself = 0, error = 0;
-       int s;
 
        KASSERT(ifp0 != sc->sc_carpdev);
        KERNEL_ASSERT_LOCKED(); /* touching vhif_vrs */
@@ -1754,9 +1750,7 @@ carp_set_ifp(struct carp_softc *sc, stru
        /* Change input handler of the physical interface. */
        if_ih_insert(ifp0, carp_input, cif);
 
-       s = splnet();
        carp_carpdev_state(ifp0);
-       splx(s);
 
        return (0);
 }