Check for space on the ring before dequeuing packets.

Allows us to get rid of mq_requeue(9) and IFQ_POLL(9) because wireless
drivers use a special queue for management frames.

Tested by stsp@, ok dlg@, stsp@

4 files changed, 32 insertions, 55 deletions

diff --git a/sys/dev/usb/if_ral.c b/sys/dev/usb/if_ral.c
index 2f906b1b2c6..08daa0829df 100644
--- a/sys/dev/usb/if_ral.c
+++ b/sys/dev/usb/if_ral.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ral.c,v 1.134 2015/11/04 12:12:00 dlg Exp $	*/
+/*	$OpenBSD: if_ral.c,v 1.135 2015/11/13 10:36:29 mpi Exp $	*/
 
 /*-
  * Copyright (c) 2005, 2006
@@ -1238,14 +1238,13 @@ ural_start(struct ifnet *ifp)
 		return;
 
 	for (;;) {
+		if (sc->tx_queued >= RAL_TX_LIST_COUNT - 1) {
+			ifp->if_flags |= IFF_OACTIVE;
+			break;
+		}
+
 		m0 = mq_dequeue(&ic->ic_mgtq);
 		if (m0 != NULL) {
-			if (sc->tx_queued >= RAL_TX_LIST_COUNT - 1) {
-				mq_requeue(&ic->ic_mgtq, m0);
-				ifp->if_flags |= IFF_OACTIVE;
-				break;
-			}
-
 			ni = m0->m_pkthdr.ph_cookie;
 #if NBPFILTER > 0
 			if (ic->ic_rawbpf != NULL)
@@ -1257,14 +1256,10 @@ ural_start(struct ifnet *ifp)
 		} else {
 			if (ic->ic_state != IEEE80211_S_RUN)
 				break;
-			IFQ_POLL(&ifp->if_snd, m0);
+
+			IFQ_DEQUEUE(&ifp->if_snd, m0);
 			if (m0 == NULL)
 				break;
-			if (sc->tx_queued >= RAL_TX_LIST_COUNT - 1) {
-				ifp->if_flags |= IFF_OACTIVE;
-				break;
-			}
-			IFQ_DEQUEUE(&ifp->if_snd, m0);
 #if NBPFILTER > 0
 			if (ifp->if_bpf != NULL)
 				bpf_mtap(ifp->if_bpf, m0, BPF_DIRECTION_OUT);
diff --git a/sys/dev/usb/if_rum.c b/sys/dev/usb/if_rum.c
index 567d20e0349..09a42757608 100644
--- a/sys/dev/usb/if_rum.c
+++ b/sys/dev/usb/if_rum.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_rum.c,v 1.113 2015/11/04 12:12:00 dlg Exp $	*/
+/*	$OpenBSD: if_rum.c,v 1.114 2015/11/13 10:36:29 mpi Exp $	*/
 
 /*-
  * Copyright (c) 2005-2007 Damien Bergamini <damien.bergamini@free.fr>
@@ -1242,14 +1242,13 @@ rum_start(struct ifnet *ifp)
 		return;
 
 	for (;;) {
+		if (sc->tx_queued >= RUM_TX_LIST_COUNT - 1) {
+			ifp->if_flags |= IFF_OACTIVE;
+			break;
+		}
+
 		m0 = mq_dequeue(&ic->ic_mgtq);
 		if (m0 != NULL) {
-			if (sc->tx_queued >= RUM_TX_LIST_COUNT - 1) {
-				mq_requeue(&ic->ic_mgtq, m0);
-				ifp->if_flags |= IFF_OACTIVE;
-				break;
-			}
-
 			ni = m0->m_pkthdr.ph_cookie;
 #if NBPFILTER > 0
 			if (ic->ic_rawbpf != NULL)
@@ -1261,14 +1260,10 @@ rum_start(struct ifnet *ifp)
 		} else {
 			if (ic->ic_state != IEEE80211_S_RUN)
 				break;
-			IFQ_POLL(&ifp->if_snd, m0);
+
+			IFQ_DEQUEUE(&ifp->if_snd, m0);
 			if (m0 == NULL)
 				break;
-			if (sc->tx_queued >= RUM_TX_LIST_COUNT - 1) {
-				ifp->if_flags |= IFF_OACTIVE;
-				break;
-			}
-			IFQ_DEQUEUE(&ifp->if_snd, m0);
 #if NBPFILTER > 0
 			if (ifp->if_bpf != NULL)
 				bpf_mtap(ifp->if_bpf, m0, BPF_DIRECTION_OUT);
diff --git a/sys/dev/usb/if_uath.c b/sys/dev/usb/if_uath.c
index 84293ed3806..1752061466c 100644
--- a/sys/dev/usb/if_uath.c
+++ b/sys/dev/usb/if_uath.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_uath.c,v 1.71 2015/11/04 12:12:00 dlg Exp $	*/
+/*	$OpenBSD: if_uath.c,v 1.72 2015/11/13 10:36:29 mpi Exp $	*/
 
 /*-
  * Copyright (c) 2006
@@ -1477,14 +1477,13 @@ uath_start(struct ifnet *ifp)
 		return;
 
 	for (;;) {
+		if (sc->tx_queued >= UATH_TX_DATA_LIST_COUNT) {
+			ifp->if_flags |= IFF_OACTIVE;
+			break;
+		}
+
 		m0 = mq_dequeue(&ic->ic_mgtq);
 		if (m0 != NULL) {
-			if (sc->tx_queued >= UATH_TX_DATA_LIST_COUNT) {
-				mq_requeue(&ic->ic_mgtq, m0);
-				ifp->if_flags |= IFF_OACTIVE;
-				break;
-			}
-
 			ni = m0->m_pkthdr.ph_cookie;
 #if NBPFILTER > 0
 			if (ic->ic_rawbpf != NULL)
@@ -1495,14 +1494,10 @@ uath_start(struct ifnet *ifp)
 		} else {
 			if (ic->ic_state != IEEE80211_S_RUN)
 				break;
-			IFQ_POLL(&ifp->if_snd, m0);
+
+			IFQ_DEQUEUE(&ifp->if_snd, m0);
 			if (m0 == NULL)
 				break;
-			if (sc->tx_queued >= UATH_TX_DATA_LIST_COUNT) {
-				ifp->if_flags |= IFF_OACTIVE;
-				break;
-			}
-			IFQ_DEQUEUE(&ifp->if_snd, m0);
 #if NBPFILTER > 0
 			if (ifp->if_bpf != NULL)
 				bpf_mtap(ifp->if_bpf, m0, BPF_DIRECTION_OUT);
diff --git a/sys/dev/usb/if_urtw.c b/sys/dev/usb/if_urtw.c
index 22f4254bb20..6ba00806ba9 100644
--- a/sys/dev/usb/if_urtw.c
+++ b/sys/dev/usb/if_urtw.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_urtw.c,v 1.56 2015/11/04 12:12:00 dlg Exp $	*/
+/*	$OpenBSD: if_urtw.c,v 1.57 2015/11/13 10:36:29 mpi Exp $	*/
 
 /*-
  * Copyright (c) 2009 Martynas Venckus <martynas@openbsd.org>
@@ -2429,15 +2429,14 @@ urtw_start(struct ifnet *ifp)
 		return;
 
 	for (;;) {
+		if (sc->sc_tx_low_queued >= URTW_TX_DATA_LIST_COUNT ||
+		    sc->sc_tx_normal_queued >= URTW_TX_DATA_LIST_COUNT) {
+			ifp->if_flags |= IFF_OACTIVE;
+			break;
+		}
+
 		m0 = mq_dequeue(&ic->ic_mgtq);
 		if (m0 != NULL) {
-			if (sc->sc_tx_low_queued >= URTW_TX_DATA_LIST_COUNT ||
-			    sc->sc_tx_normal_queued >=
-			    URTW_TX_DATA_LIST_COUNT) {
-				mq_requeue(&ic->ic_mgtq, m0);
-				ifp->if_flags |= IFF_OACTIVE;
-				break;
-			}
 			ni = m0->m_pkthdr.ph_cookie;
 #if NBPFILTER > 0
 			if (ic->ic_rawbpf != NULL)
@@ -2449,16 +2448,9 @@ urtw_start(struct ifnet *ifp)
 		} else {
 			if (ic->ic_state != IEEE80211_S_RUN)
 				break;
-			IFQ_POLL(&ifp->if_snd, m0);
+			IFQ_DEQUEUE(&ifp->if_snd, m0);
 			if (m0 == NULL)
 				break;
-			if (sc->sc_tx_low_queued >= URTW_TX_DATA_LIST_COUNT ||
-			    sc->sc_tx_normal_queued >=
-			    URTW_TX_DATA_LIST_COUNT) {
-				ifp->if_flags |= IFF_OACTIVE;
-				break;
-			}
-			IFQ_DEQUEUE(&ifp->if_snd, m0);
 #if NBPFILTER > 0
 			if (ifp->if_bpf != NULL)
 				bpf_mtap(ifp->if_bpf, m0, BPF_DIRECTION_OUT);