In preparation of merging projects/sendfile, transform bare access to

sb_cc member of struct sockbuf to a couple of inline functions:

sbavail() and sbused()

Right now they are equal, but once notion of "not ready socket buffer data",
will be checked in, they are going to be different.

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.

22 files changed, 173 insertions, 135 deletions

diff --git a/sys/dev/cxgb/ulp/iw_cxgb/iw_cxgb_cm.c b/sys/dev/cxgb/ulp/iw_cxgb/iw_cxgb_cm.c
index fea86eba709d..eba1ab72b0f0 100644
--- a/sys/dev/cxgb/ulp/iw_cxgb/iw_cxgb_cm.c
+++ b/sys/dev/cxgb/ulp/iw_cxgb/iw_cxgb_cm.c
@@ -1507,11 +1507,11 @@ process_data(struct iwch_ep *ep)
 		process_mpa_request(ep);
 		break;
 	default:
-		if (ep->com.so->so_rcv.sb_cc) 
+		if (sbavail(&ep->com.so->so_rcv)) 
 			printf("%s Unexpected streaming data."
 			       " ep %p state %d so %p so_state %x so_rcv.sb_cc %u so_rcv.sb_mb %p\n",
 			       __FUNCTION__, ep, state_read(&ep->com), ep->com.so, ep->com.so->so_state,
-			       ep->com.so->so_rcv.sb_cc, ep->com.so->so_rcv.sb_mb);
+			       sbavail(&ep->com.so->so_rcv), ep->com.so->so_rcv.sb_mb);
 		break;
 	}
 	return;
diff --git a/sys/dev/cxgb/ulp/tom/cxgb_cpl_io.c b/sys/dev/cxgb/ulp/tom/cxgb_cpl_io.c
index a86bf7207796..81a446a64a4f 100644
--- a/sys/dev/cxgb/ulp/tom/cxgb_cpl_io.c
+++ b/sys/dev/cxgb/ulp/tom/cxgb_cpl_io.c
@@ -445,8 +445,8 @@ t3_push_frames(struct socket *so, int req_completion)
 	 * Autosize the send buffer.
 	 */
 	if (snd->sb_flags & SB_AUTOSIZE && VNET(tcp_do_autosndbuf)) {
-		if (snd->sb_cc >= (snd->sb_hiwat / 8 * 7) &&
-		    snd->sb_cc < VNET(tcp_autosndbuf_max)) {
+		if (sbused(snd) >= (snd->sb_hiwat / 8 * 7) &&
+		    sbused(snd) < VNET(tcp_autosndbuf_max)) {
 			if (!sbreserve_locked(snd, min(snd->sb_hiwat +
 			    VNET(tcp_autosndbuf_inc), VNET(tcp_autosndbuf_max)),
 			    so, curthread))
@@ -597,10 +597,10 @@ t3_rcvd(struct toedev *tod, struct tcpcb *tp)
 	INP_WLOCK_ASSERT(inp);
 
 	SOCKBUF_LOCK(so_rcv);
-	KASSERT(toep->tp_enqueued >= so_rcv->sb_cc,
-	    ("%s: so_rcv->sb_cc > enqueued", __func__));
-	toep->tp_rx_credits += toep->tp_enqueued - so_rcv->sb_cc;
-	toep->tp_enqueued = so_rcv->sb_cc;
+	KASSERT(toep->tp_enqueued >= sbused(so_rcv),
+	    ("%s: sbused(so_rcv) > enqueued", __func__));
+	toep->tp_rx_credits += toep->tp_enqueued - sbused(so_rcv);
+	toep->tp_enqueued = sbused(so_rcv);
 	SOCKBUF_UNLOCK(so_rcv);
 
 	must_send = toep->tp_rx_credits + 16384 >= tp->rcv_wnd;
@@ -1768,7 +1768,7 @@ wr_ack(struct toepcb *toep, struct mbuf *m)
 		so_sowwakeup_locked(so);
 	}
 
-	if (snd->sb_sndptroff < snd->sb_cc)
+	if (snd->sb_sndptroff < sbused(snd))
 		t3_push_frames(so, 0);
 
 out_free:
diff --git a/sys/dev/cxgbe/iw_cxgbe/cm.c b/sys/dev/cxgbe/iw_cxgbe/cm.c
index d9009bdf6b88..4702e19a5866 100644
--- a/sys/dev/cxgbe/iw_cxgbe/cm.c
+++ b/sys/dev/cxgbe/iw_cxgbe/cm.c
@@ -584,8 +584,8 @@ process_data(struct c4iw_ep *ep)
 {
 	struct sockaddr_in *local, *remote;
 
-	CTR5(KTR_IW_CXGBE, "%s: so %p, ep %p, state %s, sb_cc %d", __func__,
-	    ep->com.so, ep, states[ep->com.state], ep->com.so->so_rcv.sb_cc);
+	CTR5(KTR_IW_CXGBE, "%s: so %p, ep %p, state %s, sbused %d", __func__,
+	    ep->com.so, ep, states[ep->com.state], sbused(&ep->com.so->so_rcv));
 
 	switch (state_read(&ep->com)) {
 	case MPA_REQ_SENT:
@@ -601,11 +601,11 @@ process_data(struct c4iw_ep *ep)
 		process_mpa_request(ep);
 		break;
 	default:
-		if (ep->com.so->so_rcv.sb_cc)
-			log(LOG_ERR, "%s: Unexpected streaming data.  "
-			    "ep %p, state %d, so %p, so_state 0x%x, sb_cc %u\n",
+		if (sbused(&ep->com.so->so_rcv))
+			log(LOG_ERR, "%s: Unexpected streaming data. ep %p, "
+			    "state %d, so %p, so_state 0x%x, sbused %u\n",
 			    __func__, ep, state_read(&ep->com), ep->com.so,
-			    ep->com.so->so_state, ep->com.so->so_rcv.sb_cc);
+			    ep->com.so->so_state, sbused(&ep->com.so->so_rcv));
 		break;
 	}
 }
diff --git a/sys/dev/cxgbe/tom/t4_cpl_io.c b/sys/dev/cxgbe/tom/t4_cpl_io.c
index 9af2248dede4..29e5fa243be5 100644
--- a/sys/dev/cxgbe/tom/t4_cpl_io.c
+++ b/sys/dev/cxgbe/tom/t4_cpl_io.c
@@ -365,15 +365,15 @@ t4_rcvd(struct toedev *tod, struct tcpcb *tp)
 	INP_WLOCK_ASSERT(inp);
 
 	SOCKBUF_LOCK(sb);
-	KASSERT(toep->sb_cc >= sb->sb_cc,
+	KASSERT(toep->sb_cc >= sbused(sb),
 	    ("%s: sb %p has more data (%d) than last time (%d).",
-	    __func__, sb, sb->sb_cc, toep->sb_cc));
+	    __func__, sb, sbused(sb), toep->sb_cc));
 	if (toep->ulp_mode == ULP_MODE_ISCSI) {
 		toep->rx_credits += toep->sb_cc;
 		toep->sb_cc = 0;
 	} else {
-		toep->rx_credits += toep->sb_cc - sb->sb_cc;
-		toep->sb_cc = sb->sb_cc;
+		toep->rx_credits += toep->sb_cc - sbused(sb);
+		toep->sb_cc = sbused(sb);
 	}
 	credits = toep->rx_credits;
 	SOCKBUF_UNLOCK(sb);
@@ -1079,15 +1079,15 @@ do_peer_close(struct sge_iq *iq, const struct rss_header *rss, struct mbuf *m)
 		tp->rcv_nxt = be32toh(cpl->rcv_nxt);
 		toep->ddp_flags &= ~(DDP_BUF0_ACTIVE | DDP_BUF1_ACTIVE);
 
-		KASSERT(toep->sb_cc >= sb->sb_cc,
+		KASSERT(toep->sb_cc >= sbused(sb),
 		    ("%s: sb %p has more data (%d) than last time (%d).",
-		    __func__, sb, sb->sb_cc, toep->sb_cc));
-		toep->rx_credits += toep->sb_cc - sb->sb_cc;
+		    __func__, sb, sbused(sb), toep->sb_cc));
+		toep->rx_credits += toep->sb_cc - sbused(sb);
 #ifdef USE_DDP_RX_FLOW_CONTROL
 		toep->rx_credits -= m->m_len;	/* adjust for F_RX_FC_DDP */
 #endif
 		sbappendstream_locked(sb, m);
-		toep->sb_cc = sb->sb_cc;
+		toep->sb_cc = sbused(sb);
 	}
 	socantrcvmore_locked(so);	/* unlocks the sockbuf */
 
@@ -1582,12 +1582,12 @@ do_rx_data(struct sge_iq *iq, const struct rss_header *rss, struct mbuf *m)
 		}
 	}
 
-	KASSERT(toep->sb_cc >= sb->sb_cc,
+	KASSERT(toep->sb_cc >= sbused(sb),
 	    ("%s: sb %p has more data (%d) than last time (%d).",
-	    __func__, sb, sb->sb_cc, toep->sb_cc));
-	toep->rx_credits += toep->sb_cc - sb->sb_cc;
+	    __func__, sb, sbused(sb), toep->sb_cc));
+	toep->rx_credits += toep->sb_cc - sbused(sb);
 	sbappendstream_locked(sb, m);
-	toep->sb_cc = sb->sb_cc;
+	toep->sb_cc = sbused(sb);
 	sorwakeup_locked(so);
 	SOCKBUF_UNLOCK_ASSERT(sb);
 
diff --git a/sys/dev/cxgbe/tom/t4_ddp.c b/sys/dev/cxgbe/tom/t4_ddp.c
index 3691a3b516dc..89585cf83039 100644
--- a/sys/dev/cxgbe/tom/t4_ddp.c
+++ b/sys/dev/cxgbe/tom/t4_ddp.c
@@ -224,15 +224,15 @@ insert_ddp_data(struct toepcb *toep, uint32_t n)
 	tp->rcv_wnd -= n;
 #endif
 
-	KASSERT(toep->sb_cc >= sb->sb_cc,
+	KASSERT(toep->sb_cc >= sbused(sb),
 	    ("%s: sb %p has more data (%d) than last time (%d).",
-	    __func__, sb, sb->sb_cc, toep->sb_cc));
-	toep->rx_credits += toep->sb_cc - sb->sb_cc;
+	    __func__, sb, sbused(sb), toep->sb_cc));
+	toep->rx_credits += toep->sb_cc - sbused(sb);
 #ifdef USE_DDP_RX_FLOW_CONTROL
 	toep->rx_credits -= n;	/* adjust for F_RX_FC_DDP */
 #endif
 	sbappendstream_locked(sb, m);
-	toep->sb_cc = sb->sb_cc;
+	toep->sb_cc = sbused(sb);
 }
 
 /* SET_TCB_FIELD sent as a ULP command looks like this */
@@ -459,15 +459,15 @@ handle_ddp_data(struct toepcb *toep, __be32 ddp_report, __be32 rcv_nxt, int len)
 	else
 		discourage_ddp(toep);
 
-	KASSERT(toep->sb_cc >= sb->sb_cc,
+	KASSERT(toep->sb_cc >= sbused(sb),
 	    ("%s: sb %p has more data (%d) than last time (%d).",
-	    __func__, sb, sb->sb_cc, toep->sb_cc));
-	toep->rx_credits += toep->sb_cc - sb->sb_cc;
+	    __func__, sb, sbused(sb), toep->sb_cc));
+	toep->rx_credits += toep->sb_cc - sbused(sb);
 #ifdef USE_DDP_RX_FLOW_CONTROL
 	toep->rx_credits -= len;	/* adjust for F_RX_FC_DDP */
 #endif
 	sbappendstream_locked(sb, m);
-	toep->sb_cc = sb->sb_cc;
+	toep->sb_cc = sbused(sb);
 wakeup:
 	KASSERT(toep->ddp_flags & db_flag,
 	    ("%s: DDP buffer not active. toep %p, ddp_flags 0x%x, report 0x%x",
@@ -908,7 +908,7 @@ handle_ddp(struct socket *so, struct uio *uio, int flags, int error)
 #endif
 
 	/* XXX: too eager to disable DDP, could handle NBIO better than this. */
-	if (sb->sb_cc >= uio->uio_resid || uio->uio_resid < sc->tt.ddp_thres ||
+	if (sbused(sb) >= uio->uio_resid || uio->uio_resid < sc->tt.ddp_thres ||
 	    uio->uio_resid > MAX_DDP_BUFFER_SIZE || uio->uio_iovcnt > 1 ||
 	    so->so_state & SS_NBIO || flags & (MSG_DONTWAIT | MSG_NBIO) ||
 	    error || so->so_error || sb->sb_state & SBS_CANTRCVMORE)
@@ -946,7 +946,7 @@ handle_ddp(struct socket *so, struct uio *uio, int flags, int error)
 	 * payload.
 	 */
 	ddp_flags = select_ddp_flags(so, flags, db_idx);
-	wr = mk_update_tcb_for_ddp(sc, toep, db_idx, sb->sb_cc, ddp_flags);
+	wr = mk_update_tcb_for_ddp(sc, toep, db_idx, sbused(sb), ddp_flags);
 	if (wr == NULL) {
 		/*
 		 * Just unhold the pages.  The DDP buffer's software state is
@@ -1134,8 +1134,8 @@ restart:
 
 		/* uio should be just as it was at entry */
 		KASSERT(oresid == uio->uio_resid,
-		    ("%s: oresid = %d, uio_resid = %zd, sb_cc = %d",
-		    __func__, oresid, uio->uio_resid, sb->sb_cc));
+		    ("%s: oresid = %d, uio_resid = %zd, sbused = %d",
+		    __func__, oresid, uio->uio_resid, sbused(sb)));
 
 		error = handle_ddp(so, uio, flags, 0);
 		ddp_handled = 1;
@@ -1145,7 +1145,7 @@ restart:
 
 	/* Abort if socket has reported problems. */
 	if (so->so_error) {
-		if (sb->sb_cc > 0)
+		if (sbused(sb))
 			goto deliver;
 		if (oresid > uio->uio_resid)
 			goto out;
@@ -1157,32 +1157,32 @@ restart:
 
 	/* Door is closed.  Deliver what is left, if any. */
 	if (sb->sb_state & SBS_CANTRCVMORE) {
-		if (sb->sb_cc > 0)
+		if (sbused(sb))
 			goto deliver;
 		else
 			goto out;
 	}
 
 	/* Socket buffer is empty and we shall not block. */
-	if (sb->sb_cc == 0 &&
+	if (sbused(sb) == 0 &&
 	    ((so->so_state & SS_NBIO) || (flags & (MSG_DONTWAIT|MSG_NBIO)))) {
 		error = EAGAIN;
 		goto out;
 	}
 
 	/* Socket buffer got some data that we shall deliver now. */
-	if (sb->sb_cc > 0 && !(flags & MSG_WAITALL) &&
+	if (sbused(sb) && !(flags & MSG_WAITALL) &&
 	    ((sb->sb_flags & SS_NBIO) ||
 	     (flags & (MSG_DONTWAIT|MSG_NBIO)) ||
-	     sb->sb_cc >= sb->sb_lowat ||
-	     sb->sb_cc >= uio->uio_resid ||
-	     sb->sb_cc >= sb->sb_hiwat) ) {
+	     sbused(sb) >= sb->sb_lowat ||
+	     sbused(sb) >= uio->uio_resid ||
+	     sbused(sb) >= sb->sb_hiwat) ) {
 		goto deliver;
 	}
 
 	/* On MSG_WAITALL we must wait until all data or error arrives. */
 	if ((flags & MSG_WAITALL) &&
-	    (sb->sb_cc >= uio->uio_resid || sb->sb_cc >= sb->sb_lowat))
+	    (sbused(sb) >= uio->uio_resid || sbused(sb) >= sb->sb_lowat))
 		goto deliver;
 
 	/*
@@ -1201,7 +1201,7 @@ restart:
 
 deliver:
 	SOCKBUF_LOCK_ASSERT(&so->so_rcv);
-	KASSERT(sb->sb_cc > 0, ("%s: sockbuf empty", __func__));
+	KASSERT(sbused(sb) > 0, ("%s: sockbuf empty", __func__));
 	KASSERT(sb->sb_mb != NULL, ("%s: sb_mb == NULL", __func__));
 
 	if (sb->sb_flags & SB_DDP_INDICATE && !ddp_handled)
@@ -1212,7 +1212,7 @@ deliver:
 		uio->uio_td->td_ru.ru_msgrcv++;
 
 	/* Fill uio until full or current end of socket buffer is reached. */
-	len = min(uio->uio_resid, sb->sb_cc);
+	len = min(uio->uio_resid, sbused(sb));
 	if (mp0 != NULL) {
 		/* Dequeue as many mbufs as possible. */
 		if (!(flags & MSG_PEEK) && len >= sb->sb_mb->m_len) {
diff --git a/sys/dev/iscsi/icl.c b/sys/dev/iscsi/icl.c
index f56e494fea7e..6bce18020425 100644
--- a/sys/dev/iscsi/icl.c
+++ b/sys/dev/iscsi/icl.c
@@ -758,7 +758,7 @@ icl_receive_thread(void *arg)
 		 * is enough data received to read the PDU.
 		 */
 		SOCKBUF_LOCK(&so->so_rcv);
-		available = so->so_rcv.sb_cc;
+		available = sbavail(&so->so_rcv);
 		if (available < ic->ic_receive_len) {
 			so->so_rcv.sb_lowat = ic->ic_receive_len;
 			cv_wait(&ic->ic_receive_cv, &so->so_rcv.sb_mtx);
diff --git a/sys/kern/sys_socket.c b/sys/kern/sys_socket.c
index 47cedfeab4b8..dd831ae81a66 100644
--- a/sys/kern/sys_socket.c
+++ b/sys/kern/sys_socket.c
@@ -175,16 +175,17 @@ soo_ioctl(struct file *fp, u_long cmd, void *data, struct ucred *active_cred,
 
 	case FIONREAD:
 		/* Unlocked read. */
-		*(int *)data = so->so_rcv.sb_cc;
+		*(int *)data = sbavail(&so->so_rcv);
 		break;
 
 	case FIONWRITE:
 		/* Unlocked read. */
-		*(int *)data = so->so_snd.sb_cc;
+		*(int *)data = sbavail(&so->so_snd);
 		break;
 
 	case FIONSPACE:
-		if ((so->so_snd.sb_hiwat < so->so_snd.sb_cc) ||
+		/* Unlocked read. */
+		if ((so->so_snd.sb_hiwat < sbused(&so->so_snd)) ||
 		    (so->so_snd.sb_mbmax < so->so_snd.sb_mbcnt))
 			*(int *)data = 0;
 		else
@@ -254,6 +255,7 @@ soo_stat(struct file *fp, struct stat *ub, struct ucred *active_cred,
     struct thread *td)
 {
 	struct socket *so = fp->f_data;
+	struct sockbuf *sb;
 #ifdef MAC
 	int error;
 #endif
@@ -269,15 +271,18 @@ soo_stat(struct file *fp, struct stat *ub, struct ucred *active_cred,
 	 * If SBS_CANTRCVMORE is set, but there's still data left in the
 	 * receive buffer, the socket is still readable.
 	 */
-	SOCKBUF_LOCK(&so->so_rcv);
-	if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0 ||
-	    so->so_rcv.sb_cc != 0)
+	sb = &so->so_rcv;
+	SOCKBUF_LOCK(sb);
+	if ((sb->sb_state & SBS_CANTRCVMORE) == 0 || sbavail(sb))
 		ub->st_mode |= S_IRUSR | S_IRGRP | S_IROTH;
-	ub->st_size = so->so_rcv.sb_cc - so->so_rcv.sb_ctl;
-	SOCKBUF_UNLOCK(&so->so_rcv);
-	/* Unlocked read. */
-	if ((so->so_snd.sb_state & SBS_CANTSENDMORE) == 0)
+	ub->st_size = sbavail(sb) - sb->sb_ctl;
+	SOCKBUF_UNLOCK(sb);
+
+	sb = &so->so_snd;
+	SOCKBUF_LOCK(sb);
+	if ((sb->sb_state & SBS_CANTSENDMORE) == 0)
 		ub->st_mode |= S_IWUSR | S_IWGRP | S_IWOTH;
+	SOCKBUF_UNLOCK(sb);
 	ub->st_uid = so->so_cred->cr_uid;
 	ub->st_gid = so->so_cred->cr_gid;
 	return (*so->so_proto->pr_usrreqs->pru_sense)(so, ub);
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index 706632716b1f..e2fd1f3a6a58 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -1522,12 +1522,12 @@ restart:
 	 *   2. MSG_DONTWAIT is not set
 	 */
 	if (m == NULL || (((flags & MSG_DONTWAIT) == 0 &&
-	    so->so_rcv.sb_cc < uio->uio_resid) &&
-	    so->so_rcv.sb_cc < so->so_rcv.sb_lowat &&
+	    sbavail(&so->so_rcv) < uio->uio_resid) &&
+	    sbavail(&so->so_rcv) < so->so_rcv.sb_lowat &&
 	    m->m_nextpkt == NULL && (pr->pr_flags & PR_ATOMIC) == 0)) {
-		KASSERT(m != NULL || !so->so_rcv.sb_cc,
-		    ("receive: m == %p so->so_rcv.sb_cc == %u",
-		    m, so->so_rcv.sb_cc));
+		KASSERT(m != NULL || !sbavail(&so->so_rcv),
+		    ("receive: m == %p sbavail == %u",
+		    m, sbavail(&so->so_rcv)));
 		if (so->so_error) {
 			if (m != NULL)
 				goto dontblock;
@@ -1976,7 +1976,7 @@ restart:
 
 	/* Abort if socket has reported problems. */
 	if (so->so_error) {
-		if (sb->sb_cc > 0)
+		if (sbavail(sb) > 0)
 			goto deliver;
 		if (oresid > uio->uio_resid)
 			goto out;
@@ -1988,32 +1988,32 @@ restart:
 
 	/* Door is closed.  Deliver what is left, if any. */
 	if (sb->sb_state & SBS_CANTRCVMORE) {
-		if (sb->sb_cc > 0)
+		if (sbavail(sb) > 0)
 			goto deliver;
 		else
 			goto out;
 	}
 
 	/* Socket buffer is empty and we shall not block. */
-	if (sb->sb_cc == 0 &&
+	if (sbavail(sb) == 0 &&
 	    ((so->so_state & SS_NBIO) || (flags & (MSG_DONTWAIT|MSG_NBIO)))) {
 		error = EAGAIN;
 		goto out;
 	}
 
 	/* Socket buffer got some data that we shall deliver now. */
-	if (sb->sb_cc > 0 && !(flags & MSG_WAITALL) &&
+	if (sbavail(sb) > 0 && !(flags & MSG_WAITALL) &&
 	    ((sb->sb_flags & SS_NBIO) ||
 	     (flags & (MSG_DONTWAIT|MSG_NBIO)) ||
-	     sb->sb_cc >= sb->sb_lowat ||
-	     sb->sb_cc >= uio->uio_resid ||
-	     sb->sb_cc >= sb->sb_hiwat) ) {
+	     sbavail(sb) >= sb->sb_lowat ||
+	     sbavail(sb) >= uio->uio_resid ||
+	     sbavail(sb) >= sb->sb_hiwat) ) {
 		goto deliver;
 	}
 
 	/* On MSG_WAITALL we must wait until all data or error arrives. */
 	if ((flags & MSG_WAITALL) &&
-	    (sb->sb_cc >= uio->uio_resid || sb->sb_cc >= sb->sb_hiwat))
+	    (sbavail(sb) >= uio->uio_resid || sbavail(sb) >= sb->sb_hiwat))
 		goto deliver;
 
 	/*
@@ -2027,7 +2027,7 @@ restart:
 
 deliver:
 	SOCKBUF_LOCK_ASSERT(&so->so_rcv);
-	KASSERT(sb->sb_cc > 0, ("%s: sockbuf empty", __func__));
+	KASSERT(sbavail(sb) > 0, ("%s: sockbuf empty", __func__));
 	KASSERT(sb->sb_mb != NULL, ("%s: sb_mb == NULL", __func__));
 
 	/* Statistics. */
@@ -2035,7 +2035,7 @@ deliver:
 		uio->uio_td->td_ru.ru_msgrcv++;
 
 	/* Fill uio until full or current end of socket buffer is reached. */
-	len = min(uio->uio_resid, sb->sb_cc);
+	len = min(uio->uio_resid, sbavail(sb));
 	if (mp0 != NULL) {
 		/* Dequeue as many mbufs as possible. */
 		if (!(flags & MSG_PEEK) && len >= sb->sb_mb->m_len) {
@@ -2170,9 +2170,9 @@ soreceive_dgram(struct socket *so, struct sockaddr **psa, struct uio *uio,
 	 */
 	SOCKBUF_LOCK(&so->so_rcv);
 	while ((m = so->so_rcv.sb_mb) == NULL) {
-		KASSERT(so->so_rcv.sb_cc == 0,
-		    ("soreceive_dgram: sb_mb NULL but sb_cc %u",
-		    so->so_rcv.sb_cc));
+		KASSERT(sbavail(&so->so_rcv) == 0,
+		    ("soreceive_dgram: sb_mb NULL but sbavail %u",
+		    sbavail(&so->so_rcv)));
 		if (so->so_error) {
 			error = so->so_error;
 			so->so_error = 0;
@@ -3248,7 +3248,7 @@ filt_soread(struct knote *kn, long hint)
 	so = kn->kn_fp->f_data;
 	SOCKBUF_LOCK_ASSERT(&so->so_rcv);
 
-	kn->kn_data = so->so_rcv.sb_cc - so->so_rcv.sb_ctl;
+	kn->kn_data = sbavail(&so->so_rcv) - so->so_rcv.sb_ctl;
 	if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
 		kn->kn_flags |= EV_EOF;
 		kn->kn_fflags = so->so_error;
@@ -3260,7 +3260,7 @@ filt_soread(struct knote *kn, long hint)
 		if (kn->kn_data >= kn->kn_sdata)
 			return 1;
 	} else {
-		if (so->so_rcv.sb_cc >= so->so_rcv.sb_lowat)
+		if (sbavail(&so->so_rcv) >= so->so_rcv.sb_lowat)
 			return 1;
 	}
 
@@ -3451,7 +3451,7 @@ soisdisconnected(struct socket *so)
 	sorwakeup_locked(so);
 	SOCKBUF_LOCK(&so->so_snd);
 	so->so_snd.sb_state |= SBS_CANTSENDMORE;
-	sbdrop_locked(&so->so_snd, so->so_snd.sb_cc);
+	sbdrop_locked(&so->so_snd, sbused(&so->so_snd));
 	sowwakeup_locked(so);
 	wakeup(&so->so_timeo);
 }
diff --git a/sys/netgraph/bluetooth/socket/ng_btsocket_l2cap.c b/sys/netgraph/bluetooth/socket/ng_btsocket_l2cap.c
index bab8bbbbdd85..d2e04879a9f9 100644
--- a/sys/netgraph/bluetooth/socket/ng_btsocket_l2cap.c
+++ b/sys/netgraph/bluetooth/socket/ng_btsocket_l2cap.c
@@ -1127,9 +1127,8 @@ ng_btsocket_l2cap_process_l2ca_write_rsp(struct ng_mesg *msg,
 	/*
  	 * Check if we have more data to send
  	 */
-
 	sbdroprecord(&pcb->so->so_snd);
-	if (pcb->so->so_snd.sb_cc > 0) {
+	if (sbavail(&pcb->so->so_snd) > 0) {
 		if (ng_btsocket_l2cap_send2(pcb) == 0)
 			ng_btsocket_l2cap_timeout(pcb);
 		else
@@ -2513,7 +2512,7 @@ ng_btsocket_l2cap_send2(ng_btsocket_l2cap_pcb_p pcb)
 	
 	mtx_assert(&pcb->pcb_mtx, MA_OWNED);
 
-	if (pcb->so->so_snd.sb_cc == 0)
+	if (sbavail(&pcb->so->so_snd) == 0)
 		return (EINVAL); /* XXX */
 
 	m = m_dup(pcb->so->so_snd.sb_mb, M_NOWAIT);
diff --git a/sys/netgraph/bluetooth/socket/ng_btsocket_rfcomm.c b/sys/netgraph/bluetooth/socket/ng_btsocket_rfcomm.c
index cb3753d4bf04..a2190c78a618 100644
--- a/sys/netgraph/bluetooth/socket/ng_btsocket_rfcomm.c
+++ b/sys/netgraph/bluetooth/socket/ng_btsocket_rfcomm.c
@@ -3279,7 +3279,7 @@ ng_btsocket_rfcomm_pcb_send(ng_btsocket_rfcomm_pcb_p pcb, int limit)
 	}
 
 	for (error = 0, sent = 0; sent < limit; sent ++) { 
-		length = min(pcb->mtu, pcb->so->so_snd.sb_cc);
+		length = min(pcb->mtu, sbavail(&pcb->so->so_snd));
 		if (length == 0)
 			break;
 
diff --git a/sys/netgraph/bluetooth/socket/ng_btsocket_sco.c b/sys/netgraph/bluetooth/socket/ng_btsocket_sco.c
index f0d87b3940b7..9ff0cebabb88 100644
--- a/sys/netgraph/bluetooth/socket/ng_btsocket_sco.c
+++ b/sys/netgraph/bluetooth/socket/ng_btsocket_sco.c
@@ -906,7 +906,7 @@ ng_btsocket_sco_default_msg_input(struct ng_mesg *msg, hook_p hook)
 				sbdroprecord(&pcb->so->so_snd);
 
 			/* Send more if we have any */
-			if (pcb->so->so_snd.sb_cc > 0)
+			if (sbavail(&pcb->so->so_snd) > 0)
 				if (ng_btsocket_sco_send2(pcb) == 0)
 					ng_btsocket_sco_timeout(pcb);
 
@@ -1748,7 +1748,7 @@ ng_btsocket_sco_send2(ng_btsocket_sco_pcb_p pcb)
 	mtx_assert(&pcb->pcb_mtx, MA_OWNED);
 
 	while (pcb->rt->pending < pcb->rt->num_pkts &&
-	       pcb->so->so_snd.sb_cc > 0) {
+	       sbavail(&pcb->so->so_snd) > 0) {
 		/* Get a copy of the first packet on send queue */
 		m = m_dup(pcb->so->so_snd.sb_mb, M_NOWAIT);
 		if (m == NULL) {
diff --git a/sys/netinet/accf_dns.c b/sys/netinet/accf_dns.c
index ec2b4cfb804f..85214d6d93ca 100644
--- a/sys/netinet/accf_dns.c
+++ b/sys/netinet/accf_dns.c
@@ -75,7 +75,7 @@ sohasdns(struct socket *so, void *arg, int waitflag)
 	struct sockbuf *sb = &so->so_rcv;
 
 	/* If the socket is full, we're ready. */
-	if (sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax)
+	if (sbused(sb) >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax)
 		goto ready;
 
 	/* Check to see if we have a request. */
@@ -115,14 +115,14 @@ skippacket(struct sockbuf *sb) {
 	unsigned long packlen;
 	struct packet q, *p = &q;
 
-	if (sb->sb_cc < 2)
+	if (sbavail(sb) < 2)
 		return DNS_WAIT;
 
 	q.m = sb->sb_mb;
 	q.n = q.m->m_nextpkt;
 	q.moff = 0;
 	q.offset = 0;
-	q.len = sb->sb_cc;
+	q.len = sbavail(sb);
 
 	GET16(p, packlen);
 	if (packlen + 2 > q.len)
diff --git a/sys/netinet/accf_http.c b/sys/netinet/accf_http.c
index 41e442c4fa7f..33734c717a62 100644
--- a/sys/netinet/accf_http.c
+++ b/sys/netinet/accf_http.c
@@ -92,7 +92,7 @@ sbfull(struct sockbuf *sb)
 	    "mbcnt(%ld) >= mbmax(%ld): %d",
 	    sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat,
 	    sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax);
-	return (sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax);
+	return (sbused(sb) >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax);
 }
 
 /*
@@ -162,13 +162,14 @@ static int
 sohashttpget(struct socket *so, void *arg, int waitflag)
 {
 
-	if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) {
+	if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0 &&
+	    !sbfull(&so->so_rcv)) {
 		struct mbuf *m;
 		char *cmp;
 		int	cmplen, cc;
 
 		m = so->so_rcv.sb_mb;
-		cc = so->so_rcv.sb_cc - 1;
+		cc = sbavail(&so->so_rcv) - 1;
 		if (cc < 1)
 			return (SU_OK);
 		switch (*mtod(m, char *)) {
@@ -215,7 +216,7 @@ soparsehttpvers(struct socket *so, void *arg, int waitflag)
 		goto fallout;
 
 	m = so->so_rcv.sb_mb;
-	cc = so->so_rcv.sb_cc;
+	cc = sbavail(&so->so_rcv);
 	inspaces = spaces = 0;
 	for (m = so->so_rcv.sb_mb; m; m = n) {
 		n = m->m_nextpkt;
@@ -304,7 +305,7 @@ soishttpconnected(struct socket *so, void *arg, int waitflag)
 	 * have NCHRS left
 	 */
 	copied = 0;
-	ccleft = so->so_rcv.sb_cc;
+	ccleft = sbavail(&so->so_rcv);
 	if (ccleft < NCHRS)
 		goto readmore;
 	a = b = c = '\0';
diff --git a/sys/netinet/siftr.c b/sys/netinet/siftr.c
index 9d2ca50232fe..d65564f990fa 100644
--- a/sys/netinet/siftr.c
+++ b/sys/netinet/siftr.c
@@ -782,9 +782,9 @@ siftr_siftdata(struct pkt_node *pn, struct inpcb *inp, struct tcpcb *tp,
 	pn->flags = tp->t_flags;
 	pn->rxt_length = tp->t_rxtcur;
 	pn->snd_buf_hiwater = inp->inp_socket->so_snd.sb_hiwat;
-	pn->snd_buf_cc = inp->inp_socket->so_snd.sb_cc;
+	pn->snd_buf_cc = sbused(&inp->inp_socket->so_snd);
 	pn->rcv_buf_hiwater = inp->inp_socket->so_rcv.sb_hiwat;
-	pn->rcv_buf_cc = inp->inp_socket->so_rcv.sb_cc;
+	pn->rcv_buf_cc = sbused(&inp->inp_socket->so_rcv);
 	pn->sent_inflight_bytes = tp->snd_max - tp->snd_una;
 	pn->t_segqlen = tp->t_segqlen;
 
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 625992afaef7..468f14210565 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -1745,7 +1745,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
 					tcp_timer_activate(tp, TT_REXMT,
 						      tp->t_rxtcur);
 				sowwakeup(so);
-				if (so->so_snd.sb_cc)
+				if (sbavail(&so->so_snd))
 					(void) tcp_output(tp);
 				goto check_delack;
 			}
@@ -2526,7 +2526,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
 					 * Otherwise we would send pure ACKs.
 					 */
 					SOCKBUF_LOCK(&so->so_snd);
-					avail = so->so_snd.sb_cc -
+					avail = sbavail(&so->so_snd) -
 					    (tp->snd_nxt - tp->snd_una);
 					SOCKBUF_UNLOCK(&so->so_snd);
 					if (avail > 0)
@@ -2661,10 +2661,10 @@ process_ACK:
 		cc_ack_received(tp, th, CC_ACK);
 
 		SOCKBUF_LOCK(&so->so_snd);
-		if (acked > so->so_snd.sb_cc) {
-			tp->snd_wnd -= so->so_snd.sb_cc;
+		if (acked > sbavail(&so->so_snd)) {
+			tp->snd_wnd -= sbavail(&so->so_snd);
 			mfree = sbcut_locked(&so->so_snd,
-			    (int)so->so_snd.sb_cc);
+			    (int)sbavail(&so->so_snd));
 			ourfinisacked = 1;
 		} else {
 			mfree = sbcut_locked(&so->so_snd, acked);
@@ -2790,7 +2790,7 @@ step6:
 		 * actually wanting to send this much urgent data.
 		 */
 		SOCKBUF_LOCK(&so->so_rcv);
-		if (th->th_urp + so->so_rcv.sb_cc > sb_max) {
+		if (th->th_urp + sbavail(&so->so_rcv) > sb_max) {
 			th->th_urp = 0;			/* XXX */
 			thflags &= ~TH_URG;		/* XXX */
 			SOCKBUF_UNLOCK(&so->so_rcv);	/* XXX */
@@ -2812,7 +2812,7 @@ step6:
 		 */
 		if (SEQ_GT(th->th_seq+th->th_urp, tp->rcv_up)) {
 			tp->rcv_up = th->th_seq + th->th_urp;
-			so->so_oobmark = so->so_rcv.sb_cc +
+			so->so_oobmark = sbavail(&so->so_rcv) +
 			    (tp->rcv_up - tp->rcv_nxt) - 1;
 			if (so->so_oobmark == 0)
 				so->so_rcv.sb_state |= SBS_RCVATMARK;
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
index 7919e2b72e01..160fadaea5cd 100644
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -322,7 +322,7 @@ after_sack_rexmit:
 			 * to send then the probe will be the FIN
 			 * itself.
 			 */
-			if (off < so->so_snd.sb_cc)
+			if (off < sbused(&so->so_snd))
 				flags &= ~TH_FIN;
 			sendwin = 1;
 		} else {
@@ -348,7 +348,8 @@ after_sack_rexmit:
 	 */
 	if (sack_rxmit == 0) {
 		if (sack_bytes_rxmt == 0)
-			len = ((long)ulmin(so->so_snd.sb_cc, sendwin) - off);
+			len = ((long)ulmin(sbavail(&so->so_snd), sendwin) -
+			    off);
 		else {
 			long cwin;
 
@@ -357,8 +358,8 @@ after_sack_rexmit:
 			 * sending new data, having retransmitted all the
 			 * data possible in the scoreboard.
 			 */
-			len = ((long)ulmin(so->so_snd.sb_cc, tp->snd_wnd) 
-			       - off);
+			len = ((long)ulmin(sbavail(&so->so_snd), tp->snd_wnd) -
+			    off);
 			/*
 			 * Don't remove this (len > 0) check !
 			 * We explicitly check for len > 0 here (although it 
@@ -457,12 +458,15 @@ after_sack_rexmit:
 	 * TODO: Shrink send buffer during idle periods together
 	 * with congestion window.  Requires another timer.  Has to
 	 * wait for upcoming tcp timer rewrite.
+	 *
+	 * XXXGL: should there be used sbused() or sbavail()?
 	 */
 	if (V_tcp_do_autosndbuf && so->so_snd.sb_flags & SB_AUTOSIZE) {
 		if ((tp->snd_wnd / 4 * 5) >= so->so_snd.sb_hiwat &&
-		    so->so_snd.sb_cc >= (so->so_snd.sb_hiwat / 8 * 7) &&
-		    so->so_snd.sb_cc < V_tcp_autosndbuf_max &&
-		    sendwin >= (so->so_snd.sb_cc - (tp->snd_nxt - tp->snd_una))) {
+		    sbused(&so->so_snd) >= (so->so_snd.sb_hiwat / 8 * 7) &&
+		    sbused(&so->so_snd) < V_tcp_autosndbuf_max &&
+		    sendwin >= (sbused(&so->so_snd) -
+		    (tp->snd_nxt - tp->snd_una))) {
 			if (!sbreserve_locked(&so->so_snd,
 			    min(so->so_snd.sb_hiwat + V_tcp_autosndbuf_inc,
 			     V_tcp_autosndbuf_max), so, curthread))
@@ -499,10 +503,11 @@ after_sack_rexmit:
 		tso = 1;
 
 	if (sack_rxmit) {
-		if (SEQ_LT(p->rxmit + len, tp->snd_una + so->so_snd.sb_cc))
+		if (SEQ_LT(p->rxmit + len, tp->snd_una + sbused(&so->so_snd)))
 			flags &= ~TH_FIN;
 	} else {
-		if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc))
+		if (SEQ_LT(tp->snd_nxt + len, tp->snd_una +
+		    sbused(&so->so_snd)))
 			flags &= ~TH_FIN;
 	}
 
@@ -532,7 +537,7 @@ after_sack_rexmit:
 		 */
 		if (!(tp->t_flags & TF_MORETOCOME) &&	/* normal case */
 		    (idle || (tp->t_flags & TF_NODELAY)) &&
-		    len + off >= so->so_snd.sb_cc &&
+		    len + off >= sbavail(&so->so_snd) &&
 		    (tp->t_flags & TF_NOPUSH) == 0) {
 			goto send;
 		}
@@ -660,7 +665,7 @@ dontupdate:
 	 * if window is nonzero, transmit what we can,
 	 * otherwise force out a byte.
 	 */
-	if (so->so_snd.sb_cc && !tcp_timer_active(tp, TT_REXMT) &&
+	if (sbavail(&so->so_snd) && !tcp_timer_active(tp, TT_REXMT) &&
 	    !tcp_timer_active(tp, TT_PERSIST)) {
 		tp->t_rxtshift = 0;
 		tcp_setpersist(tp);
@@ -863,7 +868,7 @@ send:
 			 * emptied:
 			 */
 			max_len = (tp->t_maxopd - optlen);
-			if ((off + len) < so->so_snd.sb_cc) {
+			if ((off + len) < sbavail(&so->so_snd)) {
 				moff = len % max_len;
 				if (moff != 0) {
 					len -= moff;
@@ -979,7 +984,7 @@ send:
 		 * give data to the user when a buffer fills or
 		 * a PUSH comes in.)
 		 */
-		if (off + len == so->so_snd.sb_cc)
+		if (off + len == sbused(&so->so_snd))
 			flags |= TH_PUSH;
 		SOCKBUF_UNLOCK(&so->so_snd);
 	} else {
diff --git a/sys/ofed/drivers/infiniband/ulp/sdp/sdp_main.c b/sys/ofed/drivers/infiniband/ulp/sdp/sdp_main.c
index 910424dd768d..a6eba64e1622 100644
--- a/sys/ofed/drivers/infiniband/ulp/sdp/sdp_main.c
+++ b/sys/ofed/drivers/infiniband/ulp/sdp/sdp_main.c
@@ -747,7 +747,7 @@ sdp_start_disconnect(struct sdp_sock *ssk)
 		    ("sdp_start_disconnect: sdp_drop() returned NULL"));
 	} else {
 		soisdisconnecting(so);
-		unread = so->so_rcv.sb_cc;
+		unread = sbused(&so->so_rcv);
 		sbflush(&so->so_rcv);
 		sdp_usrclosed(ssk);
 		if (!(ssk->flags & SDP_DROPPED)) {
@@ -1259,7 +1259,7 @@ sdp_sorecv(struct socket *so, struct sockaddr **psa, struct uio *uio,
 	/* We will never ever get anything unless we are connected. */
 	if (!(so->so_state & (SS_ISCONNECTED|SS_ISDISCONNECTED))) {
 		/* When disconnecting there may be still some data left. */
-		if (sb->sb_cc > 0)
+		if (sbavail(sb))
 			goto deliver;
 		if (!(so->so_state & SS_ISDISCONNECTED))
 			error = ENOTCONN;
@@ -1267,7 +1267,7 @@ sdp_sorecv(struct socket *so, struct sockaddr **psa, struct uio *uio,
 	}
 
 	/* Socket buffer is empty and we shall not block. */
-	if (sb->sb_cc == 0 &&
+	if (sbavail(sb) == 0 &&
 	    ((so->so_state & SS_NBIO) || (flags & (MSG_DONTWAIT|MSG_NBIO)))) {
 		error = EAGAIN;
 		goto out;
@@ -1278,7 +1278,7 @@ restart:
 
 	/* Abort if socket has reported problems. */
 	if (so->so_error) {
-		if (sb->sb_cc > 0)
+		if (sbavail(sb))
 			goto deliver;
 		if (oresid > uio->uio_resid)
 			goto out;
@@ -1290,25 +1290,25 @@ restart:
 
 	/* Door is closed.  Deliver what is left, if any. */
 	if (sb->sb_state & SBS_CANTRCVMORE) {
-		if (sb->sb_cc > 0)
+		if (sbavail(sb))
 			goto deliver;
 		else
 			goto out;
 	}
 
 	/* Socket buffer got some data that we shall deliver now. */
-	if (sb->sb_cc > 0 && !(flags & MSG_WAITALL) &&
+	if (sbavail(sb) && !(flags & MSG_WAITALL) &&
 	    ((so->so_state & SS_NBIO) ||
 	     (flags & (MSG_DONTWAIT|MSG_NBIO)) ||
-	     sb->sb_cc >= sb->sb_lowat ||
-	     sb->sb_cc >= uio->uio_resid ||
-	     sb->sb_cc >= sb->sb_hiwat) ) {
+	     sbavail(sb) >= sb->sb_lowat ||
+	     sbavail(sb) >= uio->uio_resid ||
+	     sbavail(sb) >= sb->sb_hiwat) ) {
 		goto deliver;
 	}
 
 	/* On MSG_WAITALL we must wait until all data or error arrives. */
 	if ((flags & MSG_WAITALL) &&
-	    (sb->sb_cc >= uio->uio_resid || sb->sb_cc >= sb->sb_lowat))
+	    (sbavail(sb) >= uio->uio_resid || sbavail(sb) >= sb->sb_lowat))
 		goto deliver;
 
 	/*
@@ -1322,7 +1322,7 @@ restart:
 
 deliver:
 	SOCKBUF_LOCK_ASSERT(&so->so_rcv);
-	KASSERT(sb->sb_cc > 0, ("%s: sockbuf empty", __func__));
+	KASSERT(sbavail(sb), ("%s: sockbuf empty", __func__));
 	KASSERT(sb->sb_mb != NULL, ("%s: sb_mb == NULL", __func__));
 
 	/* Statistics. */
@@ -1330,7 +1330,7 @@ deliver:
 		uio->uio_td->td_ru.ru_msgrcv++;
 
 	/* Fill uio until full or current end of socket buffer is reached. */
-	len = min(uio->uio_resid, sb->sb_cc);
+	len = min(uio->uio_resid, sbavail(sb));
 	if (mp0 != NULL) {
 		/* Dequeue as many mbufs as possible. */
 		if (!(flags & MSG_PEEK) && len >= sb->sb_mb->m_len) {
@@ -1510,7 +1510,7 @@ sdp_urg(struct sdp_sock *ssk, struct mbuf *mb)
 	if (so == NULL)
 		return;
 
-	so->so_oobmark = so->so_rcv.sb_cc + mb->m_pkthdr.len - 1;
+	so->so_oobmark = sbused(&so->so_rcv) + mb->m_pkthdr.len - 1;
 	sohasoutofband(so);
 	ssk->oobflags &= ~(SDP_HAVEOOB | SDP_HADOOB);
 	if (!(so->so_options & SO_OOBINLINE)) {
diff --git a/sys/ofed/drivers/infiniband/ulp/sdp/sdp_rx.c b/sys/ofed/drivers/infiniband/ulp/sdp/sdp_rx.c
index f8d6181c0ede..1fe5cb060fa9 100644
--- a/sys/ofed/drivers/infiniband/ulp/sdp/sdp_rx.c
+++ b/sys/ofed/drivers/infiniband/ulp/sdp/sdp_rx.c
@@ -183,7 +183,7 @@ sdp_post_recvs_needed(struct sdp_sock *ssk)
 	 * Compute bytes in the receive queue and socket buffer.
 	 */
 	bytes_in_process = (posted - SDP_MIN_TX_CREDITS) * buffer_size;
-	bytes_in_process += ssk->socket->so_rcv.sb_cc;
+	bytes_in_process += sbused(&ssk->socket->so_rcv);
 
 	return bytes_in_process < max_bytes;
 }
diff --git a/sys/rpc/clnt_vc.c b/sys/rpc/clnt_vc.c
index 67ad58f5cd1b..3899511990a6 100644
--- a/sys/rpc/clnt_vc.c
+++ b/sys/rpc/clnt_vc.c
@@ -860,7 +860,7 @@ clnt_vc_soupcall(struct socket *so, void *arg, int waitflag)
 			 * error condition
 			 */
 			do_read = FALSE;
-			if (so->so_rcv.sb_cc >= sizeof(uint32_t)
+			if (sbavail(&so->so_rcv) >= sizeof(uint32_t)
 			    || (so->so_rcv.sb_state & SBS_CANTRCVMORE)
 			    || so->so_error)
 				do_read = TRUE;
@@ -913,7 +913,7 @@ clnt_vc_soupcall(struct socket *so, void *arg, int waitflag)
 			 * buffered.
 			 */
 			do_read = FALSE;
-			if (so->so_rcv.sb_cc >= ct->ct_record_resid
+			if (sbavail(&so->so_rcv) >= ct->ct_record_resid
 			    || (so->so_rcv.sb_state & SBS_CANTRCVMORE)
 			    || so->so_error)
 				do_read = TRUE;
diff --git a/sys/rpc/svc_vc.c b/sys/rpc/svc_vc.c
index df1d86e045cd..0190a0ce3834 100644
--- a/sys/rpc/svc_vc.c
+++ b/sys/rpc/svc_vc.c
@@ -546,7 +546,7 @@ svc_vc_ack(SVCXPRT *xprt, uint32_t *ack)
 {
 
 	*ack = atomic_load_acq_32(&xprt->xp_snt_cnt);
-	*ack -= xprt->xp_socket->so_snd.sb_cc;
+	*ack -= sbused(&xprt->xp_socket->so_snd);
 	return (TRUE);
 }
 
diff --git a/sys/sys/sockbuf.h b/sys/sys/sockbuf.h
index ef80e9c14571..f9e8da4cde0b 100644
--- a/sys/sys/sockbuf.h
+++ b/sys/sys/sockbuf.h
@@ -166,6 +166,34 @@ int	sblock(struct sockbuf *sb, int flags);
 void	sbunlock(struct sockbuf *sb);
 
 /*
+ * Return how much data is available to be taken out of socket
+ * bufffer right now.
+ */
+static inline u_int
+sbavail(struct sockbuf *sb)
+{
+
+#if 0
+	SOCKBUF_LOCK_ASSERT(sb);
+#endif
+	return (sb->sb_cc);
+}
+
+/*
+ * Return how much data sits there in the socket buffer
+ * It might be that some data is not yet ready to be read.
+ */
+static inline u_int
+sbused(struct sockbuf *sb)
+{
+
+#if 0
+	SOCKBUF_LOCK_ASSERT(sb);
+#endif
+	return (sb->sb_cc);
+}
+
+/*
  * How much space is there in a socket buffer (so->so_snd or so->so_rcv)?
  * This is problematical if the fields are unsigned, as the space might
  * still be negative (cc > hiwat or mbcnt > mbmax).  Should detect
diff --git a/sys/sys/socketvar.h b/sys/sys/socketvar.h
index bfdae0d07163..dfeeede33bb2 100644
--- a/sys/sys/socketvar.h
+++ b/sys/sys/socketvar.h
@@ -208,7 +208,7 @@ struct xsocket {
 
 /* can we read something from so? */
 #define	soreadabledata(so) \
-    ((so)->so_rcv.sb_cc >= (so)->so_rcv.sb_lowat || \
+    (sbavail(&(so)->so_rcv) >= (so)->so_rcv.sb_lowat || \
 	!TAILQ_EMPTY(&(so)->so_comp) || (so)->so_error)
 #define	soreadable(so) \
 	(soreadabledata(so) || ((so)->so_rcv.sb_state & SBS_CANTRCVMORE))