diff --git a/sys/dev/usb/if_atu.c b/sys/dev/usb/if_atu.c
index 4a806d7..91912f7 100644
--- a/sys/dev/usb/if_atu.c
+++ b/sys/dev/usb/if_atu.c
@@ -1452,9 +1452,8 @@ atu_complete_attach(struct atu_softc *sc)
 	IFQ_SET_READY(&ifp->if_snd);
 
 	/* Call MI attach routine. */
-	if_initialize(ifp);
+	if_attach(ifp);
 	ieee80211_ifattach(ic);
-	if_register(ifp);
 
 	sc->sc_newstate = ic->ic_newstate;
 	ic->ic_newstate = atu_newstate;
diff --git a/sys/dev/usb/if_aue.c b/sys/dev/usb/if_aue.c
index c8ff1d1..76face1 100644
--- a/sys/dev/usb/if_aue.c
+++ b/sys/dev/usb/if_aue.c
@@ -856,9 +856,8 @@ aue_attach(device_t parent, device_t self, void *aux)
 		ifmedia_set(&mii->mii_media, IFM_ETHER | IFM_AUTO);
 
 	/* Attach the interface. */
-	if_initialize(ifp);
+	if_attach(ifp);
 	ether_ifattach(ifp, eaddr);
-	if_register(ifp);
 	rnd_attach_source(&sc->rnd_source, device_xname(sc->aue_dev),
 	    RND_TYPE_NET, RND_FLAG_DEFAULT);
 
diff --git a/sys/dev/usb/if_axe.c b/sys/dev/usb/if_axe.c
index 3ee9fbf..5698259 100644
--- a/sys/dev/usb/if_axe.c
+++ b/sys/dev/usb/if_axe.c
@@ -840,9 +840,8 @@ axe_attach(device_t parent, device_t self, void *aux)
 		ifmedia_set(&mii->mii_media, IFM_ETHER | IFM_AUTO);
 
 	/* Attach the interface. */
-	if_initialize(ifp);
+	if_attach(ifp);
 	ether_ifattach(ifp, eaddr);
-	if_register(ifp);
 	rnd_attach_source(&sc->rnd_source, device_xname(sc->axe_dev),
 	    RND_TYPE_NET, RND_FLAG_DEFAULT);
 
diff --git a/sys/dev/usb/if_axen.c b/sys/dev/usb/if_axen.c
index 110f35e..8d1e216 100644
--- a/sys/dev/usb/if_axen.c
+++ b/sys/dev/usb/if_axen.c
@@ -791,9 +791,8 @@ axen_attach(device_t parent, device_t self, void *aux)
 		ifmedia_set(&mii->mii_media, IFM_ETHER | IFM_AUTO);
 
 	/* Attach the interface. */
-	if_initialize(ifp);
+	if_attach(ifp);
 	ether_ifattach(ifp, eaddr);
-	if_register(ifp);
 	rnd_attach_source(&sc->rnd_source, device_xname(sc->axen_dev),
 	    RND_TYPE_NET, RND_FLAG_DEFAULT);
 
diff --git a/sys/dev/usb/if_cdce.c b/sys/dev/usb/if_cdce.c
index b45edaf..45cc622 100644
--- a/sys/dev/usb/if_cdce.c
+++ b/sys/dev/usb/if_cdce.c
@@ -285,9 +285,8 @@ cdce_attach(device_t parent, device_t self, void *aux)
 
 	IFQ_SET_READY(&ifp->if_snd);
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ether_ifattach(ifp, eaddr);
-	if_register(ifp);
 
 	sc->cdce_attached = 1;
 	splx(s);
diff --git a/sys/dev/usb/if_cue.c b/sys/dev/usb/if_cue.c
index 7142b88..58d3c5f 100644
--- a/sys/dev/usb/if_cue.c
+++ b/sys/dev/usb/if_cue.c
@@ -547,9 +547,8 @@ cue_attach(device_t parent, device_t self, void *aux)
 	IFQ_SET_READY(&ifp->if_snd);
 
 	/* Attach the interface. */
-	if_initialize(ifp);
+	if_attach(ifp);
 	ether_ifattach(ifp, eaddr);
-	if_register(ifp);
 	rnd_attach_source(&sc->rnd_source, device_xname(sc->cue_dev),
 	    RND_TYPE_NET, RND_FLAG_DEFAULT);
 
diff --git a/sys/dev/usb/if_kue.c b/sys/dev/usb/if_kue.c
index 946b805..77b8ceb 100644
--- a/sys/dev/usb/if_kue.c
+++ b/sys/dev/usb/if_kue.c
@@ -504,9 +504,8 @@ kue_attach(device_t parent, device_t self, void *aux)
 	IFQ_SET_READY(&ifp->if_snd);
 
 	/* Attach the interface. */
-	if_initialize(ifp);
+	if_attach(ifp);
 	ether_ifattach(ifp, sc->kue_desc.kue_macaddr);
-	if_register(ifp);
 	rnd_attach_source(&sc->rnd_source, device_xname(sc->kue_dev),
 	    RND_TYPE_NET, RND_FLAG_DEFAULT);
 
diff --git a/sys/dev/usb/if_otus.c b/sys/dev/usb/if_otus.c
index f95f618..302353d 100644
--- a/sys/dev/usb/if_otus.c
+++ b/sys/dev/usb/if_otus.c
@@ -850,9 +850,8 @@ otus_attachhook(device_t arg)
 	IFQ_SET_READY(&ifp->if_snd);
 	memcpy(ifp->if_xname, device_xname(sc->sc_dev), IFNAMSIZ);
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ieee80211_ifattach(ic);
-	if_register(ifp);
 
 	ic->ic_node_alloc = otus_node_alloc;
 	ic->ic_newassoc   = otus_newassoc;
diff --git a/sys/dev/usb/if_rum.c b/sys/dev/usb/if_rum.c
index 30f6830..49158c4 100644
--- a/sys/dev/usb/if_rum.c
+++ b/sys/dev/usb/if_rum.c
@@ -457,9 +457,8 @@ rum_attach(device_t parent, device_t self, void *aux)
 	IFQ_SET_READY(&ifp->if_snd);
 	memcpy(ifp->if_xname, device_xname(sc->sc_dev), IFNAMSIZ);
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ieee80211_ifattach(ic);
-	if_register(ifp);
 	ic->ic_newassoc = rum_newassoc;
 
 	/* override state transition machine */
diff --git a/sys/dev/usb/if_run.c b/sys/dev/usb/if_run.c
index fc77bfa..d3f3bcb 100644
--- a/sys/dev/usb/if_run.c
+++ b/sys/dev/usb/if_run.c
@@ -632,9 +632,8 @@ run_attach(device_t parent, device_t self, void *aux)
 	IFQ_SET_READY(&ifp->if_snd);
 	memcpy(ifp->if_xname, device_xname(sc->sc_dev), IFNAMSIZ);
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ieee80211_ifattach(ic);
-	if_register(ifp);
 	ic->ic_node_alloc = run_node_alloc;
 	ic->ic_newassoc = run_newassoc;
 	ic->ic_updateslot = run_updateslot;
diff --git a/sys/dev/usb/if_smsc.c b/sys/dev/usb/if_smsc.c
index 63cb924..314d0bd 100644
--- a/sys/dev/usb/if_smsc.c
+++ b/sys/dev/usb/if_smsc.c
@@ -1113,9 +1113,8 @@ smsc_attach(device_t parent, device_t self, void *aux)
 	} else
 		ifmedia_set(&mii->mii_media, IFM_ETHER | IFM_AUTO);
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ether_ifattach(ifp, sc->sc_enaddr);
-	if_register(ifp);
 
 	rnd_attach_source(&sc->sc_rnd_source, device_xname(sc->sc_dev),
 	    RND_TYPE_NET, RND_FLAG_DEFAULT);
diff --git a/sys/dev/usb/if_udav.c b/sys/dev/usb/if_udav.c
index 8c46689..e707021 100644
--- a/sys/dev/usb/if_udav.c
+++ b/sys/dev/usb/if_udav.c
@@ -315,9 +315,8 @@ udav_attach(device_t parent, device_t self, void *aux)
 
 skipmii:
 	/* attach the interface */
-	if_initialize(ifp);
+	if_attach(ifp);
 	ether_ifattach(ifp, eaddr);
-	if_register(ifp);
 
 	rnd_attach_source(&sc->rnd_source, device_xname(self),
 	    RND_TYPE_NET, RND_FLAG_DEFAULT);
diff --git a/sys/dev/usb/if_upgt.c b/sys/dev/usb/if_upgt.c
index 00c7c66..957f18a 100644
--- a/sys/dev/usb/if_upgt.c
+++ b/sys/dev/usb/if_upgt.c
@@ -449,9 +449,8 @@ upgt_attach_hook(device_t arg)
 	IFQ_SET_READY(&ifp->if_snd);
 	memcpy(ifp->if_xname, device_xname(sc->sc_dev), IFNAMSIZ);
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ieee80211_ifattach(ic);
-	if_register(ifp);
 	ic->ic_newassoc = upgt_newassoc;
 
 	sc->sc_newstate = ic->ic_newstate;
diff --git a/sys/dev/usb/if_upl.c b/sys/dev/usb/if_upl.c
index f659b61..bfe2f02 100644
--- a/sys/dev/usb/if_upl.c
+++ b/sys/dev/usb/if_upl.c
@@ -306,9 +306,8 @@ upl_attach(device_t parent, device_t self, void *aux)
 	IFQ_SET_READY(&ifp->if_snd);
 
 	/* Attach the interface. */
-	if_initialize(ifp);
+	if_attach(ifp);
 	if_register(ifp);
-	if_alloc_sadl(ifp);
 
 	bpf_attach(ifp, DLT_RAW, 0);
 	rnd_attach_source(&sc->sc_rnd_source, device_xname(sc->sc_dev),
diff --git a/sys/dev/usb/if_ural.c b/sys/dev/usb/if_ural.c
index 1476a31..be57979 100644
--- a/sys/dev/usb/if_ural.c
+++ b/sys/dev/usb/if_ural.c
@@ -499,9 +499,8 @@ ural_attach(device_t parent, device_t self, void *aux)
 		    IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ;
 	}
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ieee80211_ifattach(ic);
-	if_register(ifp);
 	ic->ic_reset = ural_reset;
 
 	/* override state transition machine */
diff --git a/sys/dev/usb/if_url.c b/sys/dev/usb/if_url.c
index 57eae41..1d54c5b 100644
--- a/sys/dev/usb/if_url.c
+++ b/sys/dev/usb/if_url.c
@@ -311,9 +311,8 @@ url_attach(device_t parent, device_t self, void *aux)
 		ifmedia_set(&mii->mii_media, IFM_ETHER | IFM_AUTO);
 
 	/* attach the interface */
-	if_initialize(ifp);
+	if_attach(ifp);
 	ether_ifattach(ifp, eaddr);
-	if_register(ifp);
 
 	rnd_attach_source(&sc->rnd_source, device_xname(self),
 	    RND_TYPE_NET, RND_FLAG_DEFAULT);
diff --git a/sys/dev/usb/if_urndis.c b/sys/dev/usb/if_urndis.c
index 5880bcb..5448fef 100644
--- a/sys/dev/usb/if_urndis.c
+++ b/sys/dev/usb/if_urndis.c
@@ -1490,9 +1490,8 @@ urndis_attach(device_t parent, device_t self, void *aux)
 		return;
 	}
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ether_ifattach(ifp, eaddr);
-	if_register(ifp);
 	sc->sc_attached = 1;
 
 	splx(s);
diff --git a/sys/dev/usb/if_urtw.c b/sys/dev/usb/if_urtw.c
index 9a71ac4..e6b1136 100644
--- a/sys/dev/usb/if_urtw.c
+++ b/sys/dev/usb/if_urtw.c
@@ -729,9 +729,8 @@ urtw_attach(device_t parent, device_t self, void *aux)
 	IFQ_SET_READY(&ifp->if_snd);
 	memcpy(ifp->if_xname, device_xname(self), IFNAMSIZ);
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ieee80211_ifattach(ic);
-	if_register(ifp);
 
 	/* override state transition machine */
 	sc->sc_newstate = ic->ic_newstate;
diff --git a/sys/dev/usb/if_urtwn.c b/sys/dev/usb/if_urtwn.c
index 75cb9b0..2294a92 100644
--- a/sys/dev/usb/if_urtwn.c
+++ b/sys/dev/usb/if_urtwn.c
@@ -439,9 +439,8 @@ urtwn_attach(device_t parent, device_t self, void *aux)
 	IFQ_SET_READY(&ifp->if_snd);
 	memcpy(ifp->if_xname, device_xname(sc->sc_dev), IFNAMSIZ);
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ieee80211_ifattach(ic);
-	if_register(ifp);
 
 	/* override default methods */
 	ic->ic_newassoc = urtwn_newassoc;
diff --git a/sys/dev/usb/if_zyd.c b/sys/dev/usb/if_zyd.c
index 36072b6..913dd41 100644
--- a/sys/dev/usb/if_zyd.c
+++ b/sys/dev/usb/if_zyd.c
@@ -426,9 +426,8 @@ zyd_complete_attach(struct zyd_softc *sc)
 		    IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ;
 	}
 
-	if_initialize(ifp);
+	if_attach(ifp);
 	ieee80211_ifattach(ic);
-	if_register(ifp);
 	ic->ic_node_alloc = zyd_node_alloc;
 	ic->ic_newassoc = zyd_newassoc;
 
diff --git a/sys/net/if.c b/sys/net/if.c
index 506331c..89011f8 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -649,18 +649,34 @@ if_register(ifnet_t *ifp)
 	TAILQ_INSERT_TAIL(&ifnet_list, ifp, if_list);
 }
 
+/*
+ * The if_percpuq framework
+ *
+ * It allows network device drivers to execute the network stack
+ * in softint (so called softint-based if_input). It utilizes
+ * softint and percpu ifqueue. It doesn't distribute any packets
+ * between CPUs, unlike pktqueue(9).
+ *
+ * Currently we support two options for device drivers to apply the framework:
+ * - Use it implicitly with less changes
+ *   - If you use if_attach in driver's _attach function and if_input in
+ *     driver's Rx interrupt handler, a packet is queued and a softint handles
+ *     the packet implicitly
+ * - Use it explicitly in each driver (recommended)
+ *   - You can use if_percpuq_* directly in your driver
+ *   - In this case, you need to allocate struct if_percpuq in driver's softc
+ *   - See wm(4) as a reference implementation
+ */
+
 static void
 if_percpuq_softint(void *arg)
 {
 	struct if_percpuq *ipq = arg;
 	struct ifnet *ifp = ipq->ipq_ifp;
 	struct mbuf *m;
-	int s;
 
-	s = splnet();
 	while ((m = if_percpuq_dequeue(ipq)) != NULL)
 		ifp->_if_input(ifp, m);
-	splx(s);
 }
 
 static void
@@ -695,10 +711,13 @@ if_percpuq_dequeue(struct if_percpuq *ipq)
 {
 	struct mbuf *m;
 	struct ifqueue *ifq;
+	int s;
 
+	s = splnet();
 	ifq = percpu_getref(ipq->ipq_ifqs);
 	IF_DEQUEUE(ifq, m);
 	percpu_putref(ipq->ipq_ifqs);
+	splx(s);
 
 	return m;
 }
@@ -759,8 +778,12 @@ if_input(struct ifnet *ifp, struct mbuf *m)
 }
 
 /*
- * Deprecated. Use if_initialize and if_register instead.
+ * DEPRECATED. Use if_initialize and if_register instead.
  * See the above comment of if_initialize.
+ *
+ * Note that it implicitly enables if_percpuq to make drivers easy to
+ * migrate softinet-based if_input without much changes. If you don't
+ * want to enable it, use if_initialize instead.
  */
 void
 if_attach(ifnet_t *ifp)