Channel API users should pick the bufring size

hvn(4) needs to be able to put up to 128 RNDIS data messages on the
channel ring each pointing up to 16 fragments in addition to a small
number of RNDIS control messages.  This simplifies accounting of
available TX descriptors in relation to the available space on the
channel ring and as a results prevents packet drops due to the ring
being full.

1 files changed, 15 insertions, 18 deletions

diff --git a/sys/dev/pv/hyperv.c b/sys/dev/pv/hyperv.c
index fd83b31d06b..b52af62cbc6 100644
--- a/sys/dev/pv/hyperv.c
+++ b/sys/dev/pv/hyperv.c
@@ -101,7 +101,7 @@ int	hv_channel_scan(struct hv_softc *);
 void	hv_process_offer(struct hv_softc *, struct hv_offer *);
 struct hv_channel *
 	hv_channel_lookup(struct hv_softc *, uint32_t);
-int	hv_channel_ring_create(struct hv_channel *, uint32_t, uint32_t);
+int	hv_channel_ring_create(struct hv_channel *, uint32_t);
 void	hv_channel_ring_destroy(struct hv_channel *);
 extern void hv_attach_icdevs(struct hv_softc *);
 int	hv_attach_devices(struct hv_softc *);
@@ -1070,38 +1070,35 @@ hv_channel_lookup(struct hv_softc *sc, uint32_t relid)
 }
 
 int
-hv_channel_ring_create(struct hv_channel *ch, uint32_t sndbuflen,
-    uint32_t rcvbuflen)
+hv_channel_ring_create(struct hv_channel *ch, uint32_t buflen)
 {
 	struct hv_softc *sc = ch->ch_sc;
 
-	sndbuflen = roundup(sndbuflen, PAGE_SIZE);
-	rcvbuflen = roundup(rcvbuflen, PAGE_SIZE);
-	ch->ch_ring = km_alloc(sndbuflen + rcvbuflen, &kv_any, &kp_zero,
-	    cold ? &kd_nowait : &kd_waitok);
+	buflen = roundup(buflen, PAGE_SIZE);
+	ch->ch_ring = km_alloc(2 * buflen, &kv_any, &kp_zero, cold ?
+	    &kd_nowait : &kd_waitok);
 	if (ch->ch_ring == NULL) {
 		printf("%s: failed to allocate channel ring\n",
 		    sc->sc_dev.dv_xname);
 		return (-1);
 	}
-	ch->ch_ring_size = sndbuflen + rcvbuflen;
+	ch->ch_ring_size = 2 * buflen;
 	ch->ch_ring_npg = ch->ch_ring_size >> PAGE_SHIFT;
 
 	memset(&ch->ch_wrd, 0, sizeof(ch->ch_wrd));
 	ch->ch_wrd.rd_ring = (struct vmbus_bufring *)ch->ch_ring;
-	ch->ch_wrd.rd_size = sndbuflen;
-	ch->ch_wrd.rd_data_size = sndbuflen - sizeof(struct vmbus_bufring);
+	ch->ch_wrd.rd_size = buflen;
+	ch->ch_wrd.rd_data_size = buflen - sizeof(struct vmbus_bufring);
 	mtx_init(&ch->ch_wrd.rd_lock, IPL_NET);
 
 	memset(&ch->ch_rrd, 0, sizeof(ch->ch_rrd));
 	ch->ch_rrd.rd_ring = (struct vmbus_bufring *)((uint8_t *)ch->ch_ring +
-	    sndbuflen);
-	ch->ch_rrd.rd_size = rcvbuflen;
-	ch->ch_rrd.rd_data_size = rcvbuflen - sizeof(struct vmbus_bufring);
+	    buflen);
+	ch->ch_rrd.rd_size = buflen;
+	ch->ch_rrd.rd_data_size = buflen - sizeof(struct vmbus_bufring);
 	mtx_init(&ch->ch_rrd.rd_lock, IPL_NET);
 
-	if (hv_handle_alloc(ch, ch->ch_ring, sndbuflen + rcvbuflen,
-	    &ch->ch_ring_gpadl)) {
+	if (hv_handle_alloc(ch, ch->ch_ring, 2 * buflen, &ch->ch_ring_gpadl)) {
 		printf("%s: failed to obtain a PA handle for the ring\n",
 		    sc->sc_dev.dv_xname);
 		hv_channel_ring_destroy(ch);
@@ -1124,8 +1121,8 @@ hv_channel_ring_destroy(struct hv_channel *ch)
 }
 
 int
-hv_channel_open(struct hv_channel *ch, void *udata, size_t udatalen,
-    void (*handler)(void *), void *arg)
+hv_channel_open(struct hv_channel *ch, size_t buflen, void *udata,
+    size_t udatalen, void (*handler)(void *), void *arg)
 {
 	struct hv_softc *sc = ch->ch_sc;
 	struct vmbus_chanmsg_chopen cmd;
@@ -1133,7 +1130,7 @@ hv_channel_open(struct hv_channel *ch, void *udata, size_t udatalen,
 	int rv;
 
 	if (ch->ch_ring == NULL &&
-	    hv_channel_ring_create(ch, PAGE_SIZE * 4, PAGE_SIZE * 4)) {
+	    hv_channel_ring_create(ch, buflen)) {
 		DPRINTF(": failed to create channel ring\n");
 		return (-1);
 	}